Control System Using Analogue VS Digital Controllers

The element linking the final control element and the measurement is the controller. The controllers are usually single loop PID controllers before the advent of computers. These are manufactures to execute PID control functions. These days the controllers can do a lot more, easily to 80 to 90% of the controllers are still PID controllers.

It is difficult to say that controllers of analogue are definitely better than digital controller. The controllers of analogue are based on mechanical parts that cause changes to the process via the final control element. These moving parts are subjected to wear and tear over time that causes the response of the process to be somewhat different with time, again like final control elements. Analogue controllers continuously control.

Digital controllers do not have mechanical moving parts. Instead the use processors to calculate the output based on the measured values. Since they do not have moving parts, they are not susceptible to deterioration with time. Digital controllers are not continuously control. They execute at very high frequencies, usually 2-3 times per second.

The controllers of analogue should not be confused with pneumatic controllers. Just because a controller is analogue does not it is pneumatic. Pneumatic controllers are those that use air instrument to pass measurement and controller signals. Electronic controllers have the advantage of not having the same amount of dead time and lag due to the compressibility of the instrument compared to pneumatic controllers.

The DCS is a control system which collects the data from the field and decides what to do with them. Data from the field can either be stored for used for simple process control, future reference, and use in conjunction with data from another part of the plant for strategies of advance control. The DCS is involving of Engineering station, history module, data historian, control modules, input and output.

Telecommunication with SCADA Packets

There are existing two types of networks in the communication world, namely circuit switched and packet switched networks. The network of circuit switched circuit establishes direct connection between two or more stations by means of switches, which is normally done with telephone dial up modem networks. It means, there is a general move towards a packet style operation where the data is handled in packet prefixed with some addressing. The networks of packet switched are more cost effective, since a dedicated network is not needed from start to finish.

Telecommunication facilities combine, switch, amplify and transmit information over chosen media. The hardware consist transmitters to convert the voice and data signals to suite the transmission media, switches wiring, routers, bridged and multiplexers to amplify and carry the signals to a receiving station.

Frame relay is a packet of network of switched. The data packets of frame relay networks may not have direct correspondence to the size of SCADA response or poll packets. A SCADA packet will often be broken up into several packets of frame relay by the network, with delays between the frame relay of data packets. Typically communication systems vendors such as Sprint, MCI and AT&T packet types, of switching use this when transporting large data through large geographical distance.

Domain Name Server and PLC-5 Controller

Domain Name Service (DNS) is enhancement that translates a user defined name into an Internet Protocol (IP) address. This enhancement requires RSLogix5, rev 5.2 or up. This enhancement is a user friendly tabular view of module information and web diagnostics.

UPP (Web User Provided Pages) allows you to create your own custom web pages to provide process information executive summaries. This page is accessible to any Internet user who has network access to the PLC-5 controller. Two types of web user provided pages are Web Custom Data Monitor page and HTML pages:
• Web Custom Data Monitor pages contains data table elements in the table form.
• HTML pages contain text, data table elements, and images.
This enhancement requires RSLogix5 rev 5.2 or up.

DNS allows an Internet Protocol address in symbolic form to be converted into the numeric IP address. This conversion is a service provided by a remote host on the network for the PLC-5 controller. With this release of PLC-5 controller Ethernet and release 5.20 or greater of RSLogix programming software, you may enter the symbolic form of the IP address as the IP address in Message Block.

The feature of Channel Configuration in RSLogix5 programming software allows you to configure a primary and secondary DNS server as well as a Default Domain Name. DNS name contains of a Domain name and a label name. You can enter the full label and domain name or just the label name when programming the message instruction. The default domain name is appended to the name of label. Label names must start with a letter and can only contains of letter, hyphens and digits.

The PLC-5 controller verifies that label name with the name servers when a message instruction with a label name is first used. The connection is made when the IP address is returned. Subsequent message instruction will not require label name verification after the connection is made.

Communication Trends Using SCADA Systems

There are some types of communication media are supported from PLC/RTU to central distributed SCADA systems via local and wide area networks as in any data communication network. A local area network is consisted with in a local geographical area such as a building or a campus and consists of few buildings with in closed proximity. It means a wide area network is a network that connects many local area networks spread across different cities at least 100 kilometers apart.

There are some types of wide area networks include:
• Analog multi point and point to point modem networks.
• Multi point and frame relay/cell relay type point networks.
• Satellite networks and wireless radio.
• Fiber optic based on networks.

Recently, the SCADA network may be built around many of the above possible combinations of transmission protocols and networks. It will be more computer power is to be provided from the SCADA hosts since more data is required to meet the information demands of the current day corporate networks. The network and communication environment they operate are to be continuously evaluated for improvements and upgraded as time goes by.

To meet the higher demand for the data, users, system designers and SCADA manufacturers started looking for higher speed devices. A very large existing infrastructure of microwave, phone lines, and private wire that operate at voice grade frequencies.

Instruction List PLC Programming

People who have experience programming microprocessors or experience with Assembler language programming will see similarities with Instruction List programming. This language contains of many lines of code, with line representing exactly one operation. It is very step by step in format and layout, which make the entry of a series of simple mathematical function easy. In other words, if the programmer uses only instructions that defined by IEC, a program written in this language can be moved easily between platforms of hardware. These advantages to make with this language vary popular in Europe, a fact that is surprising to many US programmers who prefer the ease of maintenance in the graphical languages, and place a lower premium in the program transferability. Instruction List language is a low language level and as such, will execute much faster in the PLC than a graphical language, like Ladder. This language will consume less space in memory and is also much more compact.

The simple one line text key in method supported by this language also allows for very fast program entry, no tab click, no mouse required. Program written in this language are easier to edit and display on a handheld programming unit in legacy systems, with no software or laptop required.

Despite this advantages this language provides to a programmer, it seems that service engineers and maintenance do not prefer Instruction List. Perhaps because it is less visual than Ladder and therefore more difficult to get a sense of what errors it is experiencing and what the program is doing.

It can be struggle to key in complex functions such as PID in Instruction List PLC programming similar to the issues with Ladder Diagram and increasing PLC program complexity. This also applies to complex computation of mathematical. Instruction List does not lend itself well to any structured of form programming, such as step ladder or step programming.

ABC ConfigTool One Configuration for Multiple Networks

To define the translation between the upper network and the serial sub-network is via the ABC ConfigTool. This software has an easy to use user interface and no programming required. Pre-defined function makes the translations are easily configured.

The user can define which and how much data from the upper network shall be transferred to the sub-network during configuration. Additionally specific start characters and/or trailing characters including checksum mechanisms can be defined and a complete network telegram frame is constructed. A simple object based configuration is used by Anybus Communicator instead of a complex programming language.

The ABC ConfigTool provides a wizards for Modbus-RTU based configuration and an efficient online help functionality. The configuration of ABC ConfigTool is downloaded from the PC into the Communicator. The Communicator is ready now to start the communication with its assigned devices on the sub-network.

To save the configuration into a file, the ABC CofigTool also provides the functionality. For OEM manufacturers, this makes it easy to upload pre-defined configurations for instant usage of the Communicator by their end customers.

The benefits of Communicator are:
• Flexible translation between fieldbus or Ethernet and a serial RS232/422/485 sub-network with no programming required.
• It can be reused for many other networks once a configuration is completed.
• Instant network connectivity for all devices with serial interface.
• One Communicator can connect multiple field devices.

Structured Text PLC Programming

Structured Text language resembles closely a high level computer programming language such as C or Pascal with its IF…THEN loops, CASE selectors, and line ending in semicolons. Structured Text has seen the greatest increase in adoption, the aforementioned control engineering survey indicated that of all the IEC 61131 defined programming languages.

This language perhaps best embraces the growing complexity of Programming PLC, such as the functions of process control involved in chemical or plastic manufacturing. Calculus, trigonometry, and data analysis can be implemented far easier in this language than in Instruction List or Ladder. Pointers (variables used to do indirect addressing) and decision loops allow for a more compact program implementation than can be achieved in Ladder.

The flexible Structured Text editor that is common in most packages of programming makes it easy to insert comments throughout a program, and to use line spacing and indents to emphasize related sections of code. This makes the structuring task a complex program easier. The text based, Structured Text non graphical nature is similar to Instruction List also runs much faster than Ladder programming.

An additional Structured Text benefit is that it comes closer than most of the other language in achieving the IEC 61131 standard of transferability promise. Copying and pasting Structured Text from one programming package editor to another can often be done with just a few changes, emancipating a programmer from the hardware platform. A final benefit is that recently many students graduating from engineering studies have a better background in computer languages than in the electrical wiring basics, and therefore can be more proficient in Structured Text than Ladder programming.

A disadvantage is that for many experienced previously maintenance or programmers and service personnel, the Structured Text environment is somewhat unsuitable and unfamiliar for troubleshooting. In many ways, the structure and code necessary to make this code maintenance friendly can reduce some of the advantages gained from its compactness.

cATM PACs Controllers without Programming

The cATM module is a dedicated appliance transaction module that installs in a chassis of Allen Bradley ControlLogix. This module provides controller to controller data integration between Rockwell Automation controllers and a wide variety of other controller brands and network protocols. All drivers have been included and here is no additional cost to use multiple drivers.

The cATM module provides connectivity between thousands of different devices through over 100 drivers encompassing both serial and Ethernet communications. It is not require programming. This module is a ‘configure and go’ product. When the cATM Universal gateway is configured, it is automatically and transparently executes the exchange of data between controllers with no control program changes.

The data of this module can be transferred bi-directionally between the two controllers at configured rate enabling machine to machine connectivity for horizontal integration and migration at the control level. It is also a backplane interface that enables direct access to data in the ControlLogix processor.

Features and benefits of cATM Universal Gateway are:
• Package solution, - includes all required hardware and software. The configurations are stored on-board in compact flash memory.
• Wide selection of tested drivers, includes more than 100 field tested controller and network drivers.
• Easy configurations, on board configuration interface.
• Flexible data handling, bi-directional data exchange between two connected devices.
• Designed for plant floor environments.
• Etc.

Weighing Machine Using PLC

Simulation Weighing Machine



Detail the Mechanical for Weighing Machine

Information on Numbers for Detail the Mechanical Weighing Machine :
1. Weighing
2. Cup
3. Fixed Container
4. Rotary container
5. Indicator of the Operating Panel
6. Powder, Rice, Sand, etc.
7. Container
8. Rotary shaft between the fixed containers with Rotary container
9. Frame Machine

Detail Weighing Machine using PLC

Information on Numbers for Weighing Machine using PLC :
1. Weighing with input / output external
2. Sensor Object with an infrared receiver and transmitter
3. Indicator Lights for the Empty
4. Indicator Lights for Weighing Not OK
5. Indicator Lights for Weighing OK
6. Electric Motor
7. Sensor for empty containers
8. Sensor for detection position of the Rotary container
9. Input / Output external Weighing :
=>9a. Output Weighing : GO/OK
=>9b. Input Weighing : Digital Zero Reset


Number Of Inputs and Output PLC applied :
1. Number Of Inputs PLC is 4 Input :
--- 1 Unit Input from Sensor Object (NO:2)
--- 1 Unit Input from Sensor for empty containers (NO:7)
--- 1 Unit Input from Sensor for detection position of the Rotary container (NO:8)
--- 1 Unit Input from Output Weighing : GO/OK (NO:9a)
--- Total Number Of Inputs PLC is Minimum 4 Input Unit.

2. Number Of Output PLC is 5 Output :
--- 1 Unit Output to Yellow Lights for the Empty (NO:3)
--- 1 Unit Output to Red Lights for Weighing Not OK (NO:4)
--- 1 Unit Output to Green Lights for Weighing OK (NO:5)
--- 1 Unit Output to Contactor for Electric Motor (NO:6)
--- 1 Unit Output to Input Weighing : Digital Zero Reset (NO:9b)
--- Total Number Of Outputs PLC is Minimum 5 Output Unit.


Sequence PLC Programming for Weighing Machine :

1. Weighing with value 7.0 => OK
2. Weighing with value not 7.0 => NOT OK
a. If Sensor Object (NO:2) = ON Then wait for 2 seconds AND Green Lights, Red Lights = OFF
b. After 2 seconds Then Digital Zero Reset (NO:9b) = ON AND wait for 0.5 seconds
c. After 0.5 seconds Then Electric Motor (NO:6) = ON
d. If Sensor Rotary container (NO:8) = ON Then Electric Motor (NO:6) = OFF
e. Wait for 5 seconds
f. After 5 seconds :
==>If Weighing : GO/OK (NO:9a) = ON Then Green Lights (NO:5) = ON
==>If Weighing : GO/OK (NO:9a) = OFF Then Red Lights (NO:4) = ON

3. Empty Containers
a. If Sensor for empty containers (NO:7) = OFF Then Yellow Lights (NO:3) = ON
b. If Sensor for empty containers (NO:7) = OFF AND Sensor Object (NO:2) = ON Then Green Lights, Red Lights = OFF AND All Process OFF

Download Simulation Weighing Machine :
=> 1 cycle : Weighing Machine
=> 3 cycle / Full : Weighing Machine


Can You make Program Ladder PLC ?

If Can't :

Weighing Machine Using PLC Omron

Weighing Machine Using PLC Mitsubishi

Weighing Machine Using PLC Keyence

Typical Adjustment of Motion Control MicroLogix Ultra1500

Even though the PLC and the drive are two independent systems, they must function as a complete motion control system, below are the typical adjustments:
• The position command of the Ultra 1500 accommodates open collector inputs to a maximum of 900 kHz. While the pulse train frequency output from the MicroLogix controller is limited to 20 kHz, greater frequencies can be accommodates using a third party stepper card.
• The servo drive of Allen Bradley Ultra 1500, as well as many other motion drives, requires 5V dc levels for step or direction. Recently all MicroLogix modules are powered by 24 Vdc, have 24 Vdc inputs, and have a combination 24 Vdc solid state and relay outputs.
• Ultra 1500 Step or Direction inputs are for 5V interfaces, but MicroLogix outputs are 24V. A resistor of 2.2Kohms limits current through the opto-isolated input of the Ultra 1500.
• MicroLogix inputs are wired as sourcing inputs and are active low NPN.
• The discrete inputs of Ultra 1500 are active low NPN, but are not compatible with MicroLogix FET outputs. Only MicroLogix relay outputs connect to Ultra 1500 inputs.
• To configure Ultra 1500 inputs and outputs must be using Ultraware software as below:
1. input 1 : Fault Reset
2. Input 2 : Drive Enable
3. Output 1 : Drive ready

Serial Base Devices of PLC-IOC Communications

The sign and requirement systems, market availability of specific types on instruments and collaboration with other SNS vacuum system design group resulted in instrument selection controllers with serial communications as the primary means for configuration, monitoring and control.

Although the target was to install all I/O and control in the PLC, the IOC (Input/Output Controller) was chosen to host serial instruments. Now available, serial ControlLogix modules involve IOC and PLC software development for full functionality. As the serial devices are not needed at the PLC level, the IOC was better to choose.

Driver support and device driver development is required for housing the serial ports in the IOC. Serial device support within EPICS is abundant and more of a quantity that is known.

The control logic within the PLC may require inputs from the serial devices as well as initiate control but loop time requirements are in the seconds order for which network latency would not cause problems.

Loss of PLC-IOC communication requires PLC ladder logic to be designed to handle such an event. Currently serial network layout, specifically RS-485 is in the design stages. The physical locations of performance requirements, device controllers, expected network load per device and related subsystem functions are important considerations when laying out the RS-485 networks.

It may be need to distribute the PID control loop across the PLC and the IOC. Mode change from RF control to temperature control also swaps out the measured variable and PID parameters. Typically standard PID control software does not handle this correctly. The PID software in the IOC does the control software. The configuration under the consideration is for inputs into the PLC, PID in the IOC, data transferred to the IOC, control variables to the PLC, the PLC verifies control values and issues control signals to the final control elements.

MicroLogix Motion Control Hardware Interface

The control system basically breaks down into two primary systems – the PLC and the motion hardware, when using a PLC in non-interpolated motion applications. Usually, motion hardware are consists of drives, cables and motors. The type of drive necessary for the application is determined by the type of motor, stepper or servo.

Stepper drives and motors are providing the lowest cost motion solution. The stepper drive sends signals to the motor to move a certain number of pulses in stepper applications. Stepper based systems are open loop motion systems, for instance stepper motors rarely provide feedback to the control system. If the motor can not respond correctly to pulses from the drive, the position of the stepper motor relative to what the controller commanded is lost.

In the servo systems, the servo motor usually has a built-encoder. Because the encoder is wired back to the drive, a servo system is considered to be a closed loop motion system. If the motor doesn’t move the distance requested by the PLC, the drive would generate a fault condition, which in turn can be communicated back to the PLC. The PLC can be programmed to clear the fault and start a sequence to a known position, which is typically a limit or proximity switch for the faulted axis.

Interface between IOC and PLC in the SNS Linac

The Allen Bradley ControlLogix programmable controllers are programmed with the Rockwell RSLogix5000 ladder code toolkit programming.

Two control network options were under consideration, Ethernet/IP and ControlNet protocols. ControlNet is an open real time deterministic control of standard network. The Ethernet/IP (Industrial Protocol) is an adaptation of ControlNet onto Ethernet TCP/IP.

The network of Ethernet/IP was selected. The SNS Linac Controls group developed the device driver to use this technology in the IOC (Input/Output Controller). The drawbacks to this configuration stem from the foundations of Ethernet; peer to peer, non deterministic, a multi node, collision detection, and back off scheme network. This is not suitable exactly for real time control, but it is acceptable when the traffic on a segment is limited and well known and the loop constants are slow.

The problems with ControlNet were that there is only one vendor or manufacturer, the interface board required programming which would result in programming the PLC, interface IOC and board all with the same information. The programming of the ControlNet board also requires a PC that is running Windows which would add yet other architecture to support.

ControlLogix manages the locations of memory as named variables called tags allowing for arrays and mixed type data structures as well. Optimum tag to PV transfers requires packing data into 500 byte arrays as often as possible.

PLC handling of the values of binary command from the IOC is another issue. The PLC receives IOC commands as the inputs of pulsed to be latched and tested as ladder logic inputs.

To avoid duplication of alarm checking and alarm limit parameter sets, the IOC was chosen as the location for this function. The PLC will do limit checking if related directly to the controlled process and for equipment protection. PLC data is sent to the IOC where they are checked the alarm and flagged if determined to be in alarm condition.

MicroLogix PTO Functionality

MicroLogix is a choice for non-interpolated, trapezoidal motion, both because of its Pulse Train Output functionality as well as its ability to interface with motion hardware. The MicroLogix 1200 has one 20 kHz PTO function which can provide a single axis of motion control. The MicroLogix 1500 controller has two 20 kHz PTO functions which can provide two axes of motion control. The MicroLogix 1200 and 1500 PTOs are independent of each other and can run completely separate and unique motion profiles.

The MicroLogix PTO functionality is consisting of bit, integer, and double integer status and control variables. Each variable is protected by access privileges and accessed via program logic. The type of motion is provided that is needed at a given time, the user only to write the control program to interface with these variables. This implementation method provides versatility in how the PTO functions and the user program can work together.

The command instruction to the main processor to update the corresponding PTO function basically is the PTO instruction. For instance, when the PTO instruction is scanned on a logic rung, the main system processor will update the PTO function file. It allows subsystem of PTO to run independent of the controller scan while still providing an efficient interface for main program to read status and provide PTO data.

Generate Structured Text by Simulink PLC Coder

Simulink PLC Coder generates hardware independent IEC 61131 structured text from Simulink models, Embedded MATLAB functions, and Stateflow charts. This structured text is generated in PLCopen XML and other file format supported by widely used IDEs (Integrated Development Environments). You can deploy and compile your application to numerous PLC (Programmable Logic Controller) and PAC (Programmable Automation Controller) devices.

Simulink PLC Coder generates test benches that help you to verify the structured text using PAC IDEs, PLC and other simulation tools. The features of Simulink PLC coder as following:
• Simulink support including PID controller blocks, reusable subsystems, and lookup tables.
• Stateflow support including truth tables, graphical functions, and state machines.
• Embedded MATLAB support including loop constructs, if-else statements, and math operation.
• Support to multiple data types including integer, Boolean, enumerated and floating point, as well as vectors, buses, matrices, and tunable parameters.
• DE support including B&R Automation Studio, Rockwell Automation RSLogix 5000, PLCopen XML, and 3S-Smart Software Solutions CoDeSys.

You can generate structured using Simulink PLC Coder by right clicking on a Subsystem block and select the option of PLC Coder->Generate Code for Subsystem in the resulting context menu in Simulink. You can invoke the command of plcgeneratecode, which lets you create scripts to generate structured text using an automated, repeatable build process in MATLAB.

Simulink PLC Coder can fully implement your control system models comprising feedback loops, math-intensive algorithms, mode and state logic with support for more than 130 Simulink blocks, all Stateflow constructs and many Embedded MATLAB functions. You can use Simulink PLC Coder to convert discrete time plant models into structured text for HIL (Hardware in the loop) testing. You can use alternatively Real-Time Workshop to generate code of C or C++ for HIL testing with discrete time or continuous time models. Simulink PLC Coder also provides optimizations that increase the execution speed of the structured text generation and reduce memory size.

PLC Motion Control Systems Categories

Motion control can be used in applications that can not previously bear the cost. However the servo hardware, such as drive, motor, and interconnects cables, is only part of the motion solutions. Engineers need to control functionality of a programmable control in many applications. Using a programmable control system is one of the most effective approaches to providing a complete cost-effective motion control solution that has motion capabilities.

Motion control systems can be broken down into two broad categories:
• Simple, motion of non-interpolated refers to a single axis or dual axes control. It is used for positioning – to move the object from point A to point B. For examples of simple motion include pick-and-place systems and conveyor control. A model of simple motion may have multiple axes, and each axis is controlled by independently of the other axes.
• Interpolated motion is a complex and coordinated motion. The interpolated motion has multiple axes that are constantly being positioned with regard to each other. It is used in machining processes and complex 3D positioning applications.

Selecting a control device that includes Pulse Train Output (PTO) functionality is one of the easiest and least expensive methods of implementing non-interpolated motion control. PTO functionality is the ability of a controller to accurately generate a specific number of pulses at specified frequency.

The OPC Capabilities in Industrial Applications

Automation system developers are tasked with eliminating equipment islands and improving data sharing between shop floor and top floor systems. This is more challenging when the networks of communication must support diverse, multi vendor devices, like HMIs, sensors, PLCs, and MES (Manufacturing Execution systems), as seen in manufacturing gas, oil and mineral industries. The OPC foundation creates and maintains the OPC specification for standardizing the communication between plant floor devices and enterprise systems based on general computing technology that offering unifying solution.

OPC has been applied successfully to enable greater interoperability between enterprise systems and industrial automation. The scope of OPC includes accessing current data, historical data, and alarm events. It remains a scalable technology evolving along with industry demands since OPC is an open standard maintained by the OPC Foundation.

The OPC specification addresses a lot of platform capabilities intended to improve the interoperability between devices on different industrial networks from different vendors. Some of the capabilities as following:
• Real time plant access, industrial solution vendors are providing OPC data of product coupling services and real time control applications, such as equipment conditioning monitoring software or HMIs.
• Edi (Electronic Data Interchange), OPC enables data sharing between different factory devices and corporate systems using EDI systems such as XML.
• Connectivity of ERP, solution vendors seamlessly integrated data between the ERP (enterprise resource planning) applications and the industrial automation environment.
• SOA (Service Oriented Architecture), this design framework loosely couples services with programming languages, operating systems and other technologies, which eases the effort to exchange data between applications.

The OPC foundation broadened OPC interface options beyond Microsoft COM/DCOM which could not be integrated into devices of automation running other operating systems with recent architecture changes. This meant the main OPC use case, communication Human Machine Interface (HMI) applications with automation devices, required proprietary communication link from the device to the OPC interface running on a PC.

PLC Hybrid Control Connects

PLCs were conceived originally as replacement for timers, relays, and drum sequencers, they were strictly discrete controllers. Analog I/O was added eventually, but only rudimentary operations such as alarming, basic digital conditioning, and set point monitoring were available.

Not until about 15 years ago was true process loop control, in the form of the PID algorithm, added to the PLC. This functionality was only available on high end, high priced PLCs. For industrial OEM applications with process control and discrete needs, it often was cheaper to pair a low end PLC with a single loop controller as opposed to using a high end PLC.

In similar fashion, digital communications beyond RS-232 and RS-422 were not available on low cost PLCs. Industrial OEMs that needed standard communication protocols such as Ethernet, or with a need to perform loop control, were not able to use low end PLCs.

Many industrial OEMs were forced to create their own proprietary control platforms because the market did not provide a low cost controller with analog control, discrete control, and Ethernet communication capabilities.

This state of affairs has changed dramatically in the few past years, and low end and low cost PLCs now are available with analog I/O, Ethernet communication and process control capabilities. These low cost, high performance hybrid PLCs can be extremely attractive options for many industrial machine applications.

BOC Edwards designs and builds gas delivery systems of industry of semiconductor. Its control systems perform discrete control along with controlling and monitoring of gas pressures and flow rates. The control system also interfaces with toxic gas flame detectors and leak detectors.

BOC Edwards was using a custom designed controller based on the Intel 8088 processor, but wanted to deploy hybrid PLC control. It found a low cost PLC from AutomationDirect with all of capabilities. The systems require 32 digital inputs, 16 analog inputs, and 32 digital outputs. It also needs to interface with facility monitoring systems via an OPC interface or via their own proprietary communications protocol using RS-422.

Adding an HMI in Programmable Automation Controller (PAC)

As the industrial landscape continues to move a more automated environment, engineers implementing control and monitoring applications encounter complex systems increasingly. Such industrial control systems often consist of independent PAC (Programmable Automation Controllers) managing specific, individual tasks. The control and monitoring tasks must be divided among several such PACs, networked together as these distributed systems increase in complexity. Ensuring operation properly of this distributed industrial process requires the system direction operators and managers. The distributed system is incomplete without HMI (Human Machine Interface) for more direct interaction yet while a central control “hub” is appropriate of managerial supervision.

The LabView Touch Panel module has completed the National Instruments offering for systems of managing remote by extending the environment of LabView graphical programming to rugged HMI industrial computers. This note of application discusses the benefits of the LabView Touch Panel module and provides a detailed step by step tutorial for adding an HMI to your existing PAC system.

PACs (Programmable Automation Controllers) exist in a variety of applications spanning several industries. Typical examples of s PAC include the National Instrument CompactRIO and Compact FieldPoint product lines. Each system consists an embedded controller in addition to hardware modules for input or output. The need for effective management of these remote systems is universal while their specific uses very greatly.

PACs can be deployed in the field over a wide expanse or distributed throughout a single manufacturing facility. The control system or central database provides supervisor level monitoring, but may not always be accessible immediately. They have no user interface of their own since most PACs are embedded controllers. There is a need for HMIs (Human Machine Interfaces) at key access point to complete the system.

CompactFieldPint and CompactRIO are examples of these “headless” systems; they require the use of additional hardware for a user interface. National Instruments touch panel hardware, such as the family of 12” and 6” TPCs (touch panel computers), provide a robust and compact solution for industrial HMIs.

PLC with Motion Control Capabilities

Every PLC vendor offers hybrid control technology capable of discrete, analog and motion control. The suppliers of lop control mostly offer products that can perform discrete control, but motion control is not addressed on this products. Now motion controllers are performing both discrete and motion control commonly. It is also possible to find motion controllers which capable in some level of analog process control.

The selection of controller in the market environment now is driven by the specific characteristics of each application, not by product characteristics. The various applications examination reveals that industrial OEMs are deciding what controller best suits their particular needs.

The two types of products that now compete in the market are motion controllers with discrete and analog I/O and logic, and PLCs with motion control capabilities. It seems PLCs with motion control add-on or plug-in boards to be the best of the both worlds, but it is not always the case. For instance, is PVA which makes multi-axis robotic dispensing equipment? Before settle the hybrid control, they relied in combination of PLC and motion controllers to accomplish machine functionality. PLC can work well for I/O control, but PVA run in problem trying to integrate motion with the PLC.

Parking Information using PLC Omron

PLC Omron Type CP1L-L10, Name Input / Output PLC :

INPUT PLC :
0.00 ; Ultrasonic sensor for IN detection.
0.01 ; Ultrasonic sensor for OUT detection.

OUTPUT PLC :
100.00 ; Output for "FULL" display.
100.01 ; Output for "EMPTY" display.

PLC Programming for Parking Information using PLC Omron

Change Model PLC

Reading Ladder PLC Programming for Parking Information using PLC Omron :

Step 1 :
Setting Data equal capacity of parking areas
a.If 10.00 = OFF Then D0 = 15, Instruction:MOV &15 D0
Remarks :
a.1. If capacity of parking areas = 0 Then D0 = 10, Instruction:MOV &10 D0.
a.2. If capacity of parking areas = 5 Then D0 = 10 + 5 = 15, Instruction:MOV &15 D0.
a.3. If capacity of parking areas = 1000 Then D0 = 10 + 1000 = 1010, Instruction:MOV &1010 D0.

Step 2 :
"FULL" display => ON
a.If I: 0.00 = ON Then Increments Pulse the D1 by 1(one), Instruction:@++ D1
b.If D1 equal or more than 15 ( capacity of parking areas = 5, Instruction:>= D1 D0 ) Then 10.01 = ON.
c.If 10.01 = ON Then Q: 100.00 = ON.

Step 3 :
"EMPTY" display => ON
a.If I: 0.01 = ON Then Decrements Pulse the D1 by 1(one), Instruction:@-- D1
b.If D1 less than 15 ( capacity of parking areas = 5, Instruction:< D1 D0 ) Then 10.02 = ON.
c.If 10.02 = ON Then Q: 100.01 = ON.

Step 4 :
Minimum and Maximum Limits
Minimum Limits :
a.If D1 less than 10 ( Instruction:< D1 &10 ) Then D1=10 ( Instruction:MOV &10 D1 ).
Maximum Limits :
b.If D1 more than D0/capacity of parking areas ( Instruction:> D1 D0 ) Then D0=D1 ( Instruction:MOV D0 D1 ).

Please Download Programming for CX-Programmer version 9.10 :
Parking Information using PLC Omron

See : Parking Information

Hybrids a Fit for Motion Control

Other machine builders echo many of the comments made by PVA about the hybrid motion controller advantages. In business since 1905, R.A Jones is best known for its line of high capacity, high speed production packaging machines. R.A Jones has also been performing a complete range of integration services and turnkey design for more than 25 years.

R.A Jones sources hybrid motion controllers from a variety of automation suppliers including Bosch Rexroth. Hybrid control streamlines the control architecture by removing the logic needed for handshaking between the discrete controller (PLC) and the motion controller. Removing handshaking logic means less logic overall, less hardware, quicker scan times, and less wiring. Reliability is better because there are fewer points of failure, start up are quicker because there is less debugging time, and hybrid controllers are easier to troubleshoot. It is also simpler to integrate advanced, time critical functions such as registration when I/O information and motion are controlled uniformly and feel into one central processor.

Many users think the main drawback of hybrid controllers is the proprietary programming software associated with each individual vendor’s product. Logic is not transportable from platform to platform for the exact same applications. This reinventing the wheel, going from platform to platform, is no a very good use of resources.

PLCs and others types controllers share the same problem. Vendors try to address this issue by adopting the IEC 61131 software standard in the PLC world. This standard defines five different programming languages: ladder diagram, instruction list, structured text, function block diagram, and sequential function chart.

Many software vendors have marketed Windows based software packages that use these five languages. Applications are programmed on PC and then downloaded to the desired target control engine or platform. A target can be anything from PCs and PLCs to a Windows CE box.

Hybrid Controllers of Discrete, Analog and Motion Functionality

Discrete, analog and motion control functionality are often needed for machine, skid mounted process equipment and robot builders for the systems they build. This meant figuring out how to integrate several task specific controllers to get the job done, until recently. To perform all those control functions within one integrated platform, there are hybrid controllers available now.

To define hybrid controllers as capable, there are three general types of control, discrete (on/off), analog and motion. The hybrid controller is different with special-purpose controllers that they only perform one type of control. Special purpose controllers including small PLCs (discrete), single or multi loop PID controllers (analog), and motion only controllers.

When all controllers were special-purpose, many machine builders recall a time not long ago. PLC was not invented until well in the 1960s, and vendors spent decades refining and perfecting on/off control with PLCs. The most PLC vendors began to add process control and motion control function to PLC was not until the 1990s. Before PLCs, single and multi loop controllers were used, but the discrete control function’s addition did not follow until the 1990s.

Discrete control was added by motion control vendors and some motion controllers now can also execute analog process control functions. As the dedication motion controllers have been used as long as loop controllers and the addition control functions was a fairly phenomenon.

CX-Programmer Ver 4.0 of Omron PLCs

CX-Programmer version 4.0 leverages the latest improvements in Omron CJ/CS series PLCs. There is only a few of important changes. This powerful, 32 bit Microsoft Windows based software program continues to simplify PLC program development, system diagnostics and network commissioning.

Key features and benefits:
Easier team program development.

Enhanced task programming features:
• Download and develop individual tasks.
• Allows for separate files of comment per task.
• Check for duplicate addresses between the tasks.

Intellectual property protection and security
• Protect programs from being changed.
• Write protection for monitor only mode prevents data from being overwritten.
• Protect programs from being copied.

Expand networking
• Auto online connections with the PLC from Ethernet.
• Support the new 100Base-TX Ethernet Modules: CS1W-ETN21 and CJ1W-ETN21.
• Supporting up to eight networking layers.
• Support the new Controller Link hardware: CS1W-CLK21-V1, CJ1W-CLK21-V1. New hardware support
• CJ1M-CPU21 and CJ1M-CPU11.

Easier connection to CX-simulator
• Take advantage of all CX simulator testing or debugging features.
• Launch CX simulator directly from icon on CX-Programmer toolbar.

CX-Programmer v4.0 is a significant enhancement to v3.2. The enhancements are highlighted in the benefits and key features on above. Other things that should be considered are:
• CX-Programmer is the foundation on the CX-automation suite of software tools that include an OPC server, an activeX interface (CX-ServerLite), a PC based HMI (CX-Supervisor), along with protocol communication programming software tools and motion control configuration.
• SYSWIN applications will no longer to be revised, it is in the best interest of customers to migrate to CX-Programmer.
• Version 4.0 offers direct import for programs SYSWIN and new improved utilities for converting Omron’s previous PLC programming software tools.

CX-Programmer is targeted for the IEC 61131-3 specification compliance with the release of Function Block, Sequential Function Chart and Structured Instruction support occurring within 1 to 1.5 year time period.

New Generation of Programmable Automation Controller

The characteristics of programmable automation controller are:
• The operation is using a single platform in multiple domains.
• It is integrating to controller hardware and software.
• The programming using software tools which can design the control programs.
• It is open standards
• And, provides efficient processing.
Ethernet Direct launches a new generation programmable automation controller to serve expanding machine and industrial control system development needs. This new generation is called SME system that combines the ruggedness of a PLC, a graphic display, keypad in one unit and open, flexible software architecture. SME series makes process control, data acquisition, remote equipment monitoring, plants automation, building management system and industrial machine control applications flexible and easy.

Users can build systems incorporating software capabilities such as advanced control, communication, data logging, and signal processing with rugged hardware performing logic, motion, vision and process control with SME systems.

Programmable automation controller environment is in industrially hardened to withstand use in industrial applications involving extreme temperatures, vibration, dust, electric noise.

The features of programmable automation controller’s SME series are:
• It is capable to communicate real time.
• Has fast boot speed.
• Has deterministic control
• It has multi-function.
• Open communication standards.
• Able to run PC-based control software such as Visual C#, Visual Basic, C++, etc.

PLC Hybrids in Motion

Motion control coupled with analog and/or discrete control is one of the main applications for hybrid controllers. Two primary types of products compete in this market space: PLCs with motion capabilities and discrete and analog I/O and logic.

PLCs with motion control plug in or add on board would be seem to be the best of both worlds, but this is not always the case. For instance that is PVA which makes multi axis robotic dispensing equipment. Before settling on the hybrid control, they relied on a combination of motion controllers and PLC to accomplish machine functionality. The PLC worked well for I/O control, but PVA ran into problem trying to integrate motion with the PLC. Open loop motion was easy when accuracy was not important. Close loop motion was much more headache. PVA also tried using motion modules attached to the PLC and modules of stand alone. With modules attached to the PLC, trying to debug and determine why the motors weren’t moving or why errors lights up were not as easy or apparent as it should have been. Trying to troubleshot problems in the shop or out in the field was difficult.

Some modules that were not PLC based had communication problems with PLC compounding PVA’s control issues. Proprietary communication protocols were an obvious problem, and standard protocols always seemed to have some kind of twist. Often, there was a communication problem, either written into the software or with keeping the motion controller or PLC synched together. To eliminate this problem, PVA selected a hybrid controller from Galil that features up to eight axes of motion control, eight analog inputs and 64 points of digital I/O.

PVA’s 5000 line of machine offer customers a wide functional range and can manage a dispense variety and apply operations/motion control, material curing via a control heat process (analog control) and circuit board trafficking through the work area (discrete control).

PAC the Endless Technology in Industrial Application

The PAC’s understanding is start form the PLC understanding. PAC is referring to Programmable Automation Controller while PLC is referring to Programmable Logic Controller. Compare to traditional PLC solutions, the PAC reduces overall the system costs, space and give all the best features than PLC. PAC describes as a compact controller that combines the features and capabilities of a PC-based control system with the typical of Programmable Logic Controller (PLC). In the industry, a flexibility and reliable device capable of multi tasks is required to carry out complex electromechanical processes for instance in automotive industry. A programmable automation controller must perform the real time motion with multiple input/output arrangements.

The endless technology which has ability to encompass multiple tasks requiring I/O point monitoring, control, data, exchange via OPC, and integration of factory data with enterprise systems are required to leads to the migration of typical plant floor management to modern industrial application. The common applications are in manufacturing and process automation such as, machinery control in production assembly lines, or building automation such as, controlling lighting fixtures. In application type, the control system must interface with signals from simple actuators and sensors, manage interoperability using network devices and seamless data integration.

PLC Hybrid Controllers

Skid mounted process equipment, machine, and robot builders often need discrete, analog and motion control functionality for the systems they build. This meant figuring out how to integrate several task-specific controllers to get the job done until recently. The means toward that end have changed, there are hybrid controllers now available that perform all those control functions within one integrated platform.

It defines hybrid controllers as capable of at least two of three general types of control: analog (process), discrete (on/off), and motion. Hybrid controller differ from special purpose controllers in that key only perform one type of control. Special purpose controllers typically include small PLCs (discrete), motion only controllers, and multi loop PID controllers (analog).

Many machine builders recall a time not long ago when all controllers were special purpose. PLCs were not invented until well into the 1960s, and vendor spent decades perfecting and refining on/off control with PLCs. It was not until the 1990s that most PLC vendors began to add motion control and process control functions to PLCs.

Single and multi loop controllers have been used as long as loop controllers, but the addition of other control functions is a fairly recent phenomenon. Motion control vendor’s first added discrete control, and some motion controllers now can also execute analog process control functions.

Virtually every PLC vendor offers hybrid control technology capable of analog, discrete and motion control. Most loop control suppliers offer products that also can perform discrete control, but motion is not addressed with this class of products. Motion controllers that perform both motion control and discrete control are now common and it is also possible to find motion controllers with some level of analog process control capability. Controller selection is now driven by the specific characteristics of each application, not by the products characteristics.

Improve Electrical Disturbances on PLC-based Servo Control by EPRI

EPRI will draw on the input of industrial facility operators, energy service providers, and equipment manufacturers to identify power quality issues related to PLC-based servo control systems. EPRI engineers create performance criteria for these systems and develop guidelines for making the systems less susceptible to electrical disturbances. They share case studies from voltage sag testing at numerous industrial facilities to help increase the general awareness of typical power quality problems. The case studies provide examples which manufacturers have improved the immunity of their PLC-based servo control systems.

To achieve this goal, EPRI Power Quality Test Facility designed and built a model PLC based servo control system that reflects typical factory systems. They will run automated servo control sequences while subjecting the system to assorted power disturbances. This will allow them to demonstrate the susceptibilities of particular control schemes and develop modifications in the programming of PLCs, while exploring the incorporation.

The deliverables of EPRI as following:
• Establishment of performance criteria for the response of PLC-based servo control systems to electrical disturbances.
• Design and construction of a model PLC-based servo control system to test typical factory processes.
• Developments of testing protocols.
• Testing of servo control sequences in the EPRI Power Test Facility.
• Case studies of voltage sags tests.

Smith Predictor Improve Dead Time in Siemens S7

The Smith predictor function block has six inputs and one output. The implemented predictor structure contains a FOPDT model which means that actual process dynamics are approximated with first order plus dead time dynamics. In addition to the estimated process gain, time constant and dead time and cycle (sample) time, the controller output and the process variable are needed in order to calculate that output that is going to be used as the feedback signal in the closed loop system. They cycle (sample) time must match the time interval at which the function block is executed i.e. time interval of OB processing the Smith predictor.

The Siemens S7 300/400 series is chosen as the implementation platform. The Smith predictor is based on first order plus dead time model of a process. This fact doesn’t exclude it from use with more complex processes.

As dead time increases, the process is harder to control. Dead time generally decreases gain and phase stability margin. For this reason, a smaller controller gain must be applied which decrease loop performance. The Smith predictor function block is used first with a FOPDT process, where it improved loop response and allowed use of higher controller gain. Tests were also made on an S7 simulation model of a system with second order plus dead time - SOPDT dynamics with under damped response. In this case, the FOPDT Smith predictor provided much better response compared to the loop response without the dead time compensator.

DCS Advanced Control Concepts

The continuing improvement of programmable logic controller (PLC) has provided very powerful hardware and software tools for obtaining maximum performance from control loops. The main objective of any control loop is to minimize process variability. This is the most important condition to ensure uniform product quality and thus minimize product waste. This can be applied to any industry. Keeping process parameter at their nominal values is the main requirement for any control loop.

In practice, many control loops are tuned by trial and error procedure and thus are operating far from optimal, delivering poor performance. Dead time resulting from transportation of materials and energy is often found in process industries. Processes with large dead time are found to be very hard to control. This is due to the fact that dead time reduces gain and phase margin which can lead to instability. Therefore, gain has to be limited to preserve stability which effectively reduces loop performance. In many cases, a simple PID controller can’t provide the desired loop performance, which means that more advanced control structures must be applied.

Advanced control concepts are typically implemented in Distributed Control System (DCS) and applied in large controlling and complex processes. Most DCS systems have built in functional software structures made for more advanced control designs.

Offline Commissioning of a PLC Based Control System

High speed filling and packaging line systems require high stability at specified speed and well-balanced control program under complicated control conditions to ensure high system through put. These complex programs developed to control these systems run on the Programmable Logic Controller (PLC). Muller (2001) describes a simulation based technology called “PolySim”, designed to improve the quality of these systems. The example system described uses the AutoMod simulation package.

Traditionally, the final approval testing or commissioning of a control system is performed just prior to the startup phase of the control system. Offline Commissioning of a PLC Based Control System is an expensive, risky and error prone way of developing control systems due to the limitation of testing caused by the high level of safety issues to operators and damages to machines in the testing site. (Auinger 1999; Schludermann et al. 2000; Versteegt et al. 2002). However, the use of simulation allows one to develop these systems in a safe way with less time and costs.

It creates a high speed packaging (HS) system. This article is to present a general method to map control system model to controller for testing before commissioning. It uses several Rockwell Software applications to accomplish the goal.

Home Automation System Standards

A Home Automation system (HAs) should be very versatile and should offer both basic and advanced services, from the automation of light and motorizations to the higher level functions regarding remote communication and video and audio contents. It is possible to distinguish between the automation services and the multimedia services. In the first category we can think about the control of doors, windows, tends, roller blinds and roller shutters, antitheft devices, energy saving modules, temperature or air conditioning systems and irrigation plants, etc.

The lack of many system producers is to concentrate only on a subset of the aforementioned services, while a few can provide them all.

Nowadays, the only two standards recognized worldwide are Konnex and Lonworks. The first one is regulated from the International ISO/IEC 14543-3, the European CENELEC EN 50090 and also the Chinese GB/Z 20965, while the second one is regulated by the International IEC 14908 (parts 1, 2, 3, 4), the European EN 14908 and the Chinese GB/Z 20177.

In the Konnex standard devices are connected to a line max 64 devices per line, lines are grouped into area max 15 lines per area and areas grouped to form the system max 15 areas per system. This allows a max number of 14.400 devices.

Opto 22 SNAP I/O Brain

To get this kind of local intelligence, you would expect to have to buy a mini PLC or supplementary PLC and then program it with its own programming software. Opto 22’s SNAP I/O brain does not require programming, all its functions are built in.

The following operations at the SNAP I/O brain level without additional programming:
• Thermocouple linearization.
• Engineering unit conversion.
• PID loop control.
• Temperature conversion.
• Serial device control.
• High speed counting up to 20 kHz depends on the brain and module.
• Analog scaling.
• Quadrature counting.
• Output clamping.
• Gain and offset (calibration).
• Analog ramping.
• Maximum and minimum values.
• Filter weight.
• Analog and digital totalizing.
• Watchdog timeout.
• Input latching.
• TPO (time proportional output).
• Period and frequency measurement.
• Pulse generation measurement.

The utility of free I/O configuration is included with the brain. Once the new I/O is configured, perform required functions, the brain scans its local I/O, and waits for the PLC to pick up the data.

The brain continues to run PID loops and other functions locally if communication with the PLC is lost, so a communication failure does not necessarily cause local processes to stop. If a process needs to be brought t a safe condition in the communication failure event, for instance, pumps or valves turned off, the watchdog timeout can be enabled to monitor communications, and the brain will set outputs to a predetermined level if a failure occurs.

Conformance tested by ODVA’s Test Service Providers, Opto 22’s SNAP I/O is compatible completely with Allen-Bradley CompactLogix and ControlLogix PLCs using Ethernet/IP.

The Opto 22 SNAP I/O that engineers can use now to supplement an Allen-Bradley system is regarded widely as exceptionally reliable, industrially hardened I/O. for instance, its digital-to-analog and analog-to-digital conversion process is less susceptible to noise than other I/O on the market.

PLCs Implementation to Home Automation

Home Automation (HA) is sub-branch of Building Automation, which is a discipline originated in turn from Industrial Automation which target is to control automatic machines or plants. This last one’s symbol par excellence is surely the PLC (Programmable Logic Controller). It is thus natural the presence of several common aspects between Home-Building Automation and Industrial Automation, because they afford the same problem of controlling devices by command modules, both of then located in a wide area, often using remote sensors, with the need of connecting actuators, command modules and sensors by means of a net infrastructure.

One of the main differences is that most of the time a HAs has a distributed architecture, while a machine automation system has a centralized one. This means that the program that runs on the PLC controls almost everything, while the input/output modules only execute the simple actions they are commanded for.

The criticism is obviously true, PLCs are very robust and affordable devices, and the probability of a failure is very rare. Also the error probability of fieldbuses in the communication tasks is very low, so, even in the case of centralized structure, the system could be considered affordable and stable. It is very common to use directly PLCs to implement Home Automation system.

Object Oriented Programming Integrated to PLC

In desktop application development and in university education, OOP (object oriented programming) in languages like Java or C++ is common place now. OOP has demonstrated its capability for handling complex software development problems in an elegant way and for producing reusable, flexible software components. It has reduced the development time of new software and simplified the complex software tasks solution.

On the other hand industrial controller (PLC) are mostly programmed in the languages of the IEC 61131-3 standard. While some developers can not wait to use OOP for PLC programming, others may be skeptical about the adequacy of OOP for their PLC projects. In order to address both parties, an object oriented programming (OOP) tool should satisfy the following requirements:
• Integration in a PLC development environment: Integrated with the object oriented programming (OOP) itself, ones should have integrated direct access to I/O signals, configuration of I/Os and online debugging functionality with online change and variable forcing. Advantage PLC application development has many specifics which existing C++ development tools available for many targets CPU does not address.
• Multi paradigm programming: object orientation programming (OOP) should be optional. Code programmed in the classical, procedural way should be mixable with object oriented code. Advantage: this offers the skeptics a reversible and a stepwise transition.
• OOP by extension of the IEC: Object oriented programming (OOP) PLC programming should be supported by extending IEC programming with a small set of standard object oriented features. Advantage: not having to learn a new language completely avoids a steep learning curve for PLC programmers.
• Multi lingual: object oriented programming (OOP) should be supported in all languages of the IEC 61131-3, not just in the textual IEC language ST most similar to C++ and other known object oriented languages. Advantage: textual languages can not represent certain important aspects of PLC applications clearly, like state machines and complex Boolean connection networks.

The Element of Object Oriented Programming
OOP (Object Oriented Programming) is best explained not in terms of programming language features but by its specific approach to organizing the software. A language can be called object oriented if its linguistic elements allow the programmer to express such an organization.

These are the three accepted elements of the object oriented organization:
1. Classes organize objects by similarity.
2. Objects organize the system of computational into components.
3. Sub classing organizes classes by degrees of similarity.

The fundamental characteristic of Object Oriented Programming (OOP), as opposed to classical procedural programming (C, IEC), is a new way of thinking about the system of computational: the procedural view separates the representation of the system’s state through data components (variables) from the implementation of the system’s behavior through “procedure”. The system is composed of interconnected objects in the object oriented view. Each object is a small procedural system with its own behavior and state. An object’s method can operate on its state and call the methods of other objects, to which it is connected by object references.

Advantage: assume a virtual object or real object shall be managed by your system. Is it natural to think of this as an additional data structure, whose handle you have to pass into a Windows-API or a Devices-API? Or is it more natural to think of it as a new object that brings its behavior with it and that you invoke on that object directly?

Instances of function block diagram (FBD) programming with methods are objects in CoDeSys V3. Through the standard dot notation for invoking a method, the notion is support that the method as a part of the function block instance.

In CoDeSys as in most object oriented programming languages, beside objects there are still other entities in the system of computational, like global or ”static’ procedures and global or “static” variables.

HMI-PLC XV400 Touch Displays

Decentral intelligence – the trend for secure investments for the future with automation engineering. Classical fieldbus are being continually displaced to the fieldbus level for the connection of peripheral devices by the arrival of industrial Ethernet with the TCP/IP protocol. New technologies are now offering features to combine control, visualization and data management tasks with modern networking options in a single device – the HMI-PLC.

On the one hand this approach reduces the hardware investment, and on the other hand, the engineering costs are reduced decisively by universal data management ranging from engineering to diagnostics during a malfunction.

PLC controlled automation solutions have been used for many years in various applications of different branches of industry. In spite of all optimization such as the use of fieldbusses or high performance PLC’s, the engineering effort required is considerable. Interfacing to conventional networking structures such as Ethernet TCP/IP is partly impossible or associated with considerable investment in hardware and software.

The most modern IT technologies merge with the classical PLC and HMI technologies to form the HMI-PLC. More and more components feature fieldbus interfaces such as CANopen or ProfibusDP with Ethernet. The new XV400 series fulfills these demands and offers decisive advantages for current and future automation solutions due to its performance and flexibility.

CAMD Ring Control System Upgrades

In addition to the Linac control system currently in progress, CAMD has also upgraded several ring systems to PLC based systems. These include vacuum interlocks and monitoring, TSPs, and other digital control functions.

CAMD has recently upgraded its vacuum system. There are significantly more ion pump controllers and vacuum gauge controllers than in the older system. The decision was made to replace the old control system with a combination EBC/CPU PLC system. The system no consists of one identical rack per quadrant, each containing an EBC based PLC. These PLCs monitor the readbacks for each Ion pump controller and vacuum gauge controller in the quadrant. Contact closures from the vacuum gauge controllers are sent to a CPU based PLC, which contain the Ladder logic and digital outputs necessary to close various ring valves in cases of high pressure conditions.

The initial TSP system for the CAMD storage ring contained only one sublimation controller, had no indication of the success or failure of the firing operation, and provided no indication as to how much current was applied to each filament. An upgrade was planned to provide one sublimation controller per quadrant, routing its output via a PLC controlled multiplexer, and to provide a graphical user interface with logging capability for the firing operation.

When the CAMD control system upgrade project began in early 1997, CAMD was faced with the task of integrating two separate control systems, with no reliable communications method between the two. Although CAMD’s LINAC and storage ring were both procured from Maxwell Laboratories via a single, fixed process contact, early in the design phase the Linac was subcontracted to CGR-Mev.

At the end of commissioning, the ring’s control system was a VAX/VMS based system running Vista Control VSystem Software, utilizing CAMAC, GPIB, RS232, and Allen-Bradley remote I/O communications. The Linac control system, however, was a VME/OS/9 system using custom I/O cards. While Maxwell and CAMD had specified TCP/IP access to the control system computer, subsystem acceptance tests had shown that this type of communications was not possible. If the system was “ping”ed via TCP/IP, the watchdog timers expired, and the software interlocks shutdown the Linac.

The first control system to be upgraded was the storage ring control system. Initially, the VAX was replaced with a PC/Linux based system, preserving all existing hardware interfaces. Later phases of development were focused in two areas. The first was enhancing the controls capability, including adding additional control channels for a superconducting wiggler and additional corrector magnets, and increasing logging and operator automation. The second area was reducing the dependence on CAMAC and proprietary Allen Bradley protocols, and allowing remote data acquisition.

Linac Control System

The current Linac control system is based on a VME computer with custom I/O components. A custom scanner card in the VME crate using a dual-port memory map protocol communicates with the I/O cards via a 50-pin ribbon cable using a CGR-Mev in house protocol. Each I/O card is homogenous in that all digital I/O is a TTL signal, and all analog I/O utilizes a 0-10V signal. Each card is given it address via external TTL voltages. The cards have ribbon cable connector on one side, and connect to a 3U Eurocard backplane that handles all incoming and outgoing control signals. This backplane then connects to any signal specific hardware necessary, such as TTL to 24V contact relays, voltage to frequency converters, or directly to the devices controlled.

As all I/O is homogeneous at the Eurocard backplane, this is the point at which the conversion from the old control system to the new PLC system will take place. Special cables have been fabricated to connect D-shell DIN-rail breakout boxes to the 96-pin backplane connectors. Using this setup, the new control system can be tested, and the Linac can be reverted to the old control system simply by removing the adapter cables, and reinserting the I/O cards as before.

PLC Control System Integration

The AutomationDirect.com DL405 series PLCs have two different types of base controllers: the Dl405 CPUs and the Ethernet Base Controller (EBC). The DL405 CPU’s provide traditional CPU/Ladder Logic type control of the PLC, whereas the EBC eliminates the CPU, and provides “pass thru” to allow the PC to control the PLC’s I/O directly.

In combination with the DL405 CPU, the Ethernet communications module allows the PC to read and write the PLC’s memory without special communication software in the PLC. This led to the idea of using a “dual port” memory model, where machine status and other parameters are communicated between the PLC and the control PC thru the PLC’s memory. This provides a system with PLC type control, but PC based remote configurability.

Channel information for CAMD’s control system is stored in a PostgreSQL database, and is organized by device type, with device specific parameters as needed. As the CAMAC channel information is organized by crate, slot, channel address, and channel type, this seemed logical approach to organize the PLC channel information. For the EBC type controller, this provided an exact match for the access method that the communications library provides.

For the CPU based controllers, additional abstraction is necessary. The DL405 CPU architecture provides a flexible memory map: inputs, outputs, control registers, and timers can be accessed directly, or as a “V memory” address.

SNAP PAC Controllers and PAC Project Software

Programmable Automation Controllers (PACs) are multifunctional, multi-domain, modular controllers based on open standards and providing integrated development environment. Opto22 has been manufacturing PACs for many years. The latest models include the standalone SNAP PAC S-series and the rack mounted SNAO PAC R-series. Both handle a wide range of digital, analog, and serial functions and are equally suited to data collection, remote monitoring, process control and discrete and hybrid manufacturing.

SNAP PACs are based on open Ethernet and Internet Protocol (IP) standards, so you can build or extend a system without the expense and limitations of proprietary networks and protocols.

Opto 22’s PAC Project Software Suite provides full featured and cost effective control programming, HMI development and runtime, OPC server, and database connectivity software to power your SNAP PAC System.

These fully integrated software applications share a single tag name database, so the data points you configure in PAC Control are immediately available for use in PAC Display, OptoOPC Server, and Opto DataLink.

PAC Project Basic offers control and HMI tools for free. PAC Project Professional, available for separately, adds Opto OPCServer, Opto DataLink, options for Ethernet link redundancy or segmented networking, and support for legacy Opto 22 serial mistic I/O units.

Value Proposition for End Users of Foundation Fieldbus

End users are increasingly specifying automation products and services no based upon the level of technology they provide, but on the business value propositions of Foundation technology include process integrity, business intelligence, and open and scalable integration of information across process manufacturing plants.

Foundation Technology provides a path to greater process integrity through its capabilities for field level control, enhanced diagnostics for process safety systems. Providing a common architecture for both processes and safety systems, a providing more accurate measurements. Enhanced business intelligence is provided by the unification of Foundation Technology with the OPC UA standard and through the open data access that fieldbus can provide to any plant application. Open scalable integration is possible with Foundation Technology through its ability to interface with OPC UA and provide a unified data model with the incorporation of Enhanced Electronic Device Description technology.

In addition, Foundation is the only technology incorporating key aspects of the “Collaborative Process Automation System” vision, including common data, common time, common presentation, high availability, and network management.

The goal of selecting a digital fieldbus should be to deliver business benefits to the customer. Whether the user is seeking faster commissioning, better diagnostics, better performance, or increased system integrity, Foundation fieldbus is an excellent choice to achieve these objectives.

Parking Information using PLC Mitsubishi

PLC Type FX2N(C) Mitsubishi, Name Input/Output PLC :

INPUT PLC :
X000 ; Ultrasonic sensor for IN detection.
X001 ; Ultrasonic sensor for OUT detection.

OUTPUT PLC :
Y000 ; Output for "FULL" display.
Y001 ; Output for "EMPTY" display.

PLC Programming for Parking Information using PLC Mitsubishi

Setting PLC Parameter for Device Latch:



Reading Ladder PLC Programming for Parking Information using PLC Mitsubishi :

Step 1 :
Setting Data equal capacity of parking areas
a.If M100 = OFF Then D201 = 15.
Remarks :
a.1. If capacity of parking areas = 0 Then D201 = 10.
a.2. If capacity of parking areas = 5 Then D201 = 10 + 5 = 15.
a.3. If capacity of parking areas = 1000 Then D201 = 10 + 1000 = 1010.

Step 2 :
"FULL" display => ON
a.If X000 = ON Then Increments Pulse the D200 by 1(one).
b.If D200 equal or more than 15 ( capacity of parking areas = 5 ) Then M0 = ON.
c.If M0 = ON Then Y000 = ON.

Step 3 :
"EMPTY" display => ON
a.If X001 = ON Then Decrements Pulse the D200 by 1(one).
b.If D200 less than 15 ( capacity of parking areas = 5 ) Then M1 = ON.
c.If M1 = ON Then Y001 = ON.

Step 4 :
Minimum and Maximum Limits
Minimum Limits :
a.If D200 less than 10 ( [< D200 K10] ) Then D200=10 ( [MOV K10 D200] ).
Maximum Limits :
b.If D200 more than D201/capacity of parking areas ( [> D200 D201] ) Then D201=D200 ( [MOV D201 D200] ).

Please Download Programming for GX Developer :
Parking Information using PLC Mitsubishi

See : Parking Information

Deployment Areas of Programmable Automation Controller (PAC)

Understanding what a PAC is starts from the understanding of PLC. A PAC reduces overall system cost, space and gives you all the best features compared to traditional IPC + PLC solutions. Wikipedia describes PAC as a compact controller the combine the capabilities and features of a PC based control system with that of a typical PLC (Programmable Logic Controller). A reliable device is capable to operate multiple tasks, flexibility in operation and strong computing power is required to carry out complex electromechanical processes such as in automation industry. Real time motion with multiple input and/or output arrangements must be performed by a programmable automation controller.

Endless technology improvement leads to the migration of typical floor plant management to modern industrial application which requires the ability to encompass multiple tasks requiring I/O point control, monitoring, data exchange via OPC, and integration of factory data with enterprise systems. PAC area deployment can be unlimited. The most common applications are in process automation and manufacturing such as the control of machinery on factory assembly lines, or in building automation such as controlling lighting fixtures and more. The control system must interface with signals from simple actuators and sensors, network devices to manage interoperability and seamless data integration.

A PAC is often used in industrial applications for data acquisition, process control, remote equipment monitoring, motion control, and machine vision. A PAC communicates and functions over popular network interface protocols like TCP/IP, OPC (OLE for Process Control) and SMTP. PACs are able to transfer data from the machines they control to other components and machines in networked control system or to application databases and software. A PAC at the core of an automation system can integrate multiple field bus networks like RS-232, RS-422, RS-485, CAN, Ethernet, Ethernet/IP, and others. To control industrial system development and serve expanding machine needs, Ethernet Direct launches a new generation of PAC.

SITOP Power Supply for PLC Application

Since the characteristics of machines vary considerably, no one PLC can satisfy all machine control requirements. Therefore, Siemens provides PLCs of varying sizes and capabilities. The Siemens SIMATIC family’s of PLCs include the 505, S5, and the S7-200, S7-300, and S7-400.

Depending on the application, PLCs, operator panels, and control components may require a regulated power supply. The SITOP power supply provides a regulated source of 24VDC power and the ability to ride through momentary power dips between 3 to 10 ms. Longer ride through times can be achieved with an optional back up module which can provide up to 100 ms at 40 amps. An optional DC UPS (Uninterruptable Power Supply) module and an external battery are also available.

SITOP power supplies meet standards of agencies worldwide. They are suitable for use on worldwide networks and require no fusing on the secondary. Models are available up to 40 amps and SITOP can be used 100% of the rates output current.

An S7-200 PLC is mounted in a machine’s control panel. The manufacturer of the machine has chosen to use field devices that require 24 VDC power. The power for the field devices and the PLC is provided by SITOP power supplies, one of which is shown adjacent to the S7-200.

A PLC Control of SINUMERIK CNC Machine

PLCs are not the only control systems used for machines. Machine tools such as lathes, grinding machines, and machining centers are used to produce precisely machined parts. Machine tools typically combine a PLC control system with a computer numerical control (CNC). CNC-controlled machine tools allow parts to be machined to complex and exacting specifications. A gear, similar to the one illustrated, is one example of a part that might be made with a CNC-controlled machine tool.

Siemens offers a range of SINUMERIK CNC models such as the 810D, 840Di, 840D, and the compact FM357-2 positioning and path control module. These products provide the coordinated multi-axis control needed for milling, drilling, turning, and grinding applications. SINUMERIK CNCs also interconnect operator panels and SIMODRIVE servo and spindle drives and associated motors to form a complete control system for the machine tool.

Typically, machine tools are designed to perform a specific task, such as grinding, drilling, or cutting. Machine tools can be programmed to a predetermined pattern or model to obtain the desired shape of the finished piece. In the following example a SINUMERIK CNC controls a rotary grinding machine. The rotary grinding machines takes a piece of stock that has already been cut and shaped on another machine tool, removes any burrs or high spots, and grinds the material to a fine finish.

Developed System for SNS Linac Cooling & Vacuum with PLC

External contractors are developing the vacuum control and the local cooling systems for the Spallation Neutron Source (SNS) linac. Soon these systems will be integrated into the facility wide controls system. Allen-Bradley Logic5000 series programmable controllers, populated with appropriate input and output modules, were selected as the local controllers. These controllers is interfaced to the facility wide control system via VME systems with PowerPC processors running the Wind River VxWorks operating system and EPICS (Experimental Physics and Industrial Control System) front end controller software.

Through much of the SNS, PLC (Programmable Logic Controller) will be used for the local controller systems. The EPICS IOC (Input/Output Controller) provide alarm functions, supervisory control and serve as the interface point for the PLC to global controls, the machine protection system and the event link system.

The local control integration systems to EPICS require resolution of interface issues preferably during design but in some cases issues are discovered during integration and development. The more significant issues identified during design and development of the DTL (Drift Tube Linac) and CCL (Coupled Cavity Linac), RCCS (Resonance Control and Cooling System) and vacuum systems. The issues examined were:
Interface between IOC and PLC; selection of protocol communication, creating and reaching agreement on signal lists, mapping process variables, optimizing data transfer between IOC and PLC.

Serial based devices; use of serial ports on PLC, serial types and network layout, device driver development, and distributed control.
Control loops over Ethernet, PID loops dispersed over PLC and IOC on non dedicated networks.

EPICS Operator displays and control vs PLC displays; development and maintenance of local PanelView displays, cost, redundant control screens on different platforms.

Alarm checking and management; the IOC as the appropriate location for checking the alarm functions versus the PLC, alarm limit parameter maintenance. Each of these integration and interface issues follow but first a brief background of the CCL RCCS and SNS DTL and vacuum systems.

Siemens WinCC to Communicate Many Types of PLCs

Since assembly processes vary in complexity, the types of control systems and related devices employed will also vary. In addition to small and medium sized PLCs or other control systems used to control individual machines, one or more larger PLCs may be employed to collect data and coordinate operation of some or all of the system. This overall coordination may include control of the full range of motor control devices discussed thus far from full voltage starters to AC and DC drives.

The specific PLC model used will be determined by the size and complexity of the application. Examples of Siemens PLC models that may be employed include the S7-300 and S7-400.

Just as it is often necessary to use a PLC to coordinate the operation of multiple machines in an assembly process, it is often also necessary to provide a graphical representation of the current status of this process. In addition to providing this graphical representation, a Human Machine Interface (HMI), such as Siemens WinCC, can provide a custom interface to allow operation personnel to control some or all the process and for maintenance personnel to obtain system diagnostic information.

Since many manufacturing facilities use multiple PLC models and often models produced by multiple companies, WinCC can communicate with many types of PLCs. In addition, WinCC versions are available for computers using Windows 95 or Windows NT operating systems.

The PAC Systems RX3i Controller

The PAC Motion controller is a versatile 4 axis servo motion controller that provides the flexibility and scalability to cover a full range of motion applications from small material handling applications to complex multi axis electronics and machines line shaft applications. PAC Motion provides real time of all axes synchronization in an RX3i rack. A separate RX3i fast logic scan enables fast deterministic event synchronization and response, and the demand driven data exchange model between the RX3i CPU and PAC Motion module many reduce significantly scan time impact. The 4 axis servo motion controller is built on a high performance hardware platform, with new operating system, enhanced motion engine, and open standard integrated programming paradigm.

The PAC System RX3i controller is an incredibly powerful PAC (Programmable Automation Controller) in the innovative PAC Systems family. The RX3i features a universal programming environment and a single control engine to provide application portability across multiple hardware platforms and deliver a true convergence of control.

With integrated critical control platforms, motion, logic, HMI, process control and high availability based on our Reflective Memory technology, the RX3i provides the performance and flexibility to give you an advantage. PAC Systems RX3i lets you take control no matter the challenges.

The innovative technology of the PAC Systems RX3i enables users to:
• Address major business and engineering issues, such as tighter cost control and higher productivity.
• Boost the overall performance at their systems automation.
• Reduce commissioning and engineering costs.
• Easily integrate new technology into installed base systems.
• Decrease significantly concerns regarding short and long term migration and platform longevity.

PAC Systems RX3i features:
• High speed processor for faster throughput without information bottlenecks.
• Dual backplane bus support per module slot:
• Serial backplane for easy migration of existing series 90-30 I/O.
• High speed PCI.
• Memory for ladder machine documentation and logic documentation in the controller to improve troubleshooting and reduce downtime.
• Open communications support including Ethernet, Profibus etc.