Elevator with PLC Program

Simulation : elevator plc program for one Floor



Detail Elevator with PLC :

Information on Drawing Numbers for Elevator PLC Program :
(1). Push Button Switch ( Push Button Switch with Light ) In Floor B Outside.

(2). Light Push Button Switch ( Push Button Switch with Light ) In Floor B Outside.

(3). Push Button Switch ( Push Button Switch with Light ) In Floor 1 Outside.

(4). Light Push Button Switch ( Push Button Switch with Light ) In Floor 1 Outside.

(5). Push Button Switch ( Push Button Switch with Light ) In B Inside.

(6). Light Push Button Switch ( Push Button Switch with Light ) In B Inside.

(7). Push Button Switch ( Push Button Switch with Light ) In 1 Inside.

(8). Light Push Button Switch ( Push Button Switch with Light ) In 1 Inside.

(9). Limit Switch for Position 1
(10). Limit Switch for Position B
(11). Limit Switch for Door Open
(12). Limit Switch for Door Close
(13). Safety Sensor


Number Of Inputs and Output PLC applied :
1. Number Of Inputs PLC is 9 Input :
--- 1 Unit Input for Push Button Switch In Floor B Outside.
--- 1 Unit Input for Push Button Switch In Floor B Inside.
--- 1 Unit Input for Push Button Switch In Floor 1 Outside.
--- 1 Unit Input for Push Button Switch In Floor 1 Inside.
--- 1 Unit Input for Limit Switch Position 1.
--- 1 Unit Input for Limit Switch Position B.
--- 1 Unit Input for Limit Switch Door Open.
--- 1 Unit Input for Limit Switch Door Close.
--- 1 Unit Input for Safety Sensor.
--- Total Number Of Inputs PLC is Minimum 9 Input Unit.


2. Number Of Output PLC is 8 Output :
--- 1 Unit Output for Electric Motors ( Move To Position B )
--- 1 Unit Output for Electric Motors ( Move To Position 1 )
--- 1 Unit Output for Move the Door Open
--- 1 Unit Output for Move the Door Close
--- 1 Unit Output for Light Push Button Switch in B Inside
--- 1 Unit Output for Light Push Button Switch in 1 Inside
--- 1 Unit Output for Light Push Button Switch in B Outside
--- 1 Unit Output for Light Push Button Switch in 1 Outside
--- Total Number Of Outputs PLC is Minimum 8 Output Unit.


Sequence PLC Programming for Elevator PLC Program :

Step 1 : Elevator Up - Down ( 1 - B )
a. If Push Button B Outside = ON And the elevator was not in a position B Then elevator Move to B.
b. If Push Button B Inside = ON And the elevator was not in a position B Then elevator Move to B.
c. If Push Button 1 Outside = ON And the elevator was not in a position 1 Then elevator Move to 1.
d. If Push Button 1 Inside = ON And the elevator was not in a position 1 Then elevator Move to 1.


Step 2 : Door Open - Close
a. IF Limit Switch Position B = ON (Pulse / diff.Up) Or Limit Switch Position 1 = ON (Pulse / diff.Up) then Door Open.
b. IF Limit Switch Door Open = ON Or Safety Sensor = ON then Door Close.
c. Continuously to Step 1

Download Simulation Elevator PLC Program :
Elevator PLC Program


Can You make Program Ladder PLC ?

If Can't :

Elevator PLC Program with PLC Omron

Elevator PLC Program with PLC Mitsubishi

Elevator PLC Program with PLC Keyence

Automating Manufacturing Systems with PLCs

Automating manufacturing is the use of control systems such as computers to control industrial machinery and processes, replacing human operators. In the scope of industrialization, it is a step beyond mechanization. Whereas mechanization provided human operators with machinery to assist them with the physical requirements of work, automation greatly reduces the need for human sensory and mental requirements as well.

PLCs are well-adapted to a range of automation tasks. These are typically industrial processes in manufacturing where the cost of developing and maintaining the automation system is high relative to the total cost of the automation, and where changes to the system would be expected during its operational life. PLCs contain input and output devices compatible with industrial pilot devices and controls; little electrical design is required, and the design problem centers on expressing the desired sequence of operations.

PLC applications are typically highly customized systems so the cost of a packaged PLC is low compared to the cost of a specific custom-built controller design. On the other hand, in the case of mass-produced goods, customized control systems are economic due to the lower cost of the components, which can be optimally chosen instead of a "generic" solution, and where the non-recurring engineering charges are spread over thousands or millions of units.

The main advantage of the automated manufacturing are: higher consistency and quality, reduce the lead times, simplification of production, reduce handling, improve work flow and increase the morale of workers when a good implementation of the automation is made.

Application of Servo Motor

Example Simulation : Applications servo motor




Information for Applications servo motor :
1. Push Button Switch with Light for Start Operation / Zero Position.
2. Push Button Switch with Light for Positioning Start.
4. Limit Switch to Zero Position.
3. Ball Screw with gear lead (µm/rev) = 10mm.
4. Servo Motor.
5. Servo Amplifier.
6. PLC MELSEC-Q.
7. Positioning Module QD75M1.


Number Of Inputs and Output PLC applied :
1. Number Of Inputs PLC is 2 Input :
--- 1 Unit Input for Push Button Switch for Start Operation.
--- 1 Unit Input for Push Button Switch for Positioning Start.
--- Total Number Of Inputs PLC is Minimum 2 Input Unit.


2. Number Of Output PLC is 2 Output :
--- 1 Unit Output for Light Push Button Switch in Start Operation / Zero Position.
--- 1 Unit Output for Light Push Button Switch in Positioning Start.
--- Total Number Of Outputs PLC is Minimum 2 Output Unit.


Sequence for Application of Servo Motor with PLC MELSEC-Q ( Mitsubishi ):

Step 1 : Start Operation / Zero Position
a. If Push Button Start OPR = ON Then JOG = ON ( Manual Operation To LS Zero ) .
b. If LS Zero = ON Then Start OPR = ON in Positioning Module QD75M1.
c. Waiting Servo to Positioning Operation Complete.


Step 2 : Positoning Start
a. If Push Button Start = ON Then Positoning Start No.1 = RUN ( To 20mm ) And Waiting Positioning Complete.
b. If Positioning Complete = ON Then Positoning Start No.2 = RUN ( To 40mm ) And Waiting Positioning Complete.

Download Simulation : Application Servo Motor


In this application, we use a servo motor and PLC from Mitsubishi.
That needs to consider in using servo motors are:
1. Servo Wiring Diagram
2. Programming Servo Motors

Servo Wiring Diagram

Here's an example Servo Wiring Diagram for Q-series PLC from Mitsubishi, Positioning module, servo amplifier and motor servo.
Servo Wiring Diagram

PLC for application of servo motor

Component is needed for the servo wiring diagram is:
1. Q62P PLC Power Supply ( MELSEC-Q Mitsubishi ).
2. CPU unit Q02CPU ( MELSEC-Q Mitsubishi ).
3. Positioning Module QD75M1 ( MELSEC-Q Mitsubishi ).
4. Servo amplifier MR-J2S-B ( Mitsubishi ).
5. MR Buss Cable J2HBUS1M ( Mitsubishi ).
6. End Terminal MR-A-TM ( Mitsubishi ).
7. Limit Switch to Zero Position .
8. Encoder cable JCCBL05M MR-H ( Mitsubishi ).
9. MR-PWCNK2 connector ( Mitsubishi ).
10. Servo motor HC-KFS73 ( Mitsubishi ).

Download all Servo Wiring Diagram : Servo Wiring

See : Application of Servo Motor

Programming Servo Motors

1. Positioning Module QD75M1 parameters:

2. Servo Amplifier (MR-J2S-B) and Servo Motor (HC-KFS73) Parameter :

3. Start Operation
For Start Operation X20 = ON

4. Positioning Data
4.a. Positioning Data No.1

4.b. Positioning Data No.2

5. Positioning Start No.1 and No.2
For positioning Start X21 = ON


Download Programming Servo Motors: Programming Servo Motors

Download Servo amplifiers and Motors (MR-J2S) Instruction Manual: Servo amplifier

Download Type QD75M Positioning Module User's Manual: Positioning Module

See : Application of Servo Motor

The Configuration of DCS

DCS (Distributed Control System) is a control system that can collect (acquire) data from the field and decided to do with that data.

What is DCS Consists?

1. Operator Console
This tool is similar to a computer monitor. Used to provide feedback information about what is being done or done in the factory.

2. Engineering Station
This is station to the technicians who used to configure the system and also implement the control algorithm.

3. History Module
This tool is similar to the computer hard drive. This tool is used to store the configuration DC and all points in the configuration of the plant.

4. Data Historian
Usually this is software that used to store process variables, set point and output values.

5. Control Modules
It's like a brain of DCS. This is where the control functions carried out, such as PID control, control comparisons, ratio control, simple arithmetic operations and dynamic compensation.

6. Input Output (I/O)
This section is used to handle input and output from DCS. These Inputs and outputs can be analog or digital.

All the elements described are connected in one network (currently using the technology or even wireless Ethernet, WiFi or WiMax).

Currently the differences between DCS, PLC or computer control are increasingly blurred. What distinguishes more in the software levels.

Internal Architecture of PLC

According to the function PLC has three main functions. They are processing (to execute program logic instruction), Memory (to store the processing result), and Input / Output (to receive data from outside and transmit the processing result).

Internal architecture of PLC consists of CPU that is containing a microprocessors system, memory, and a series of input / output. CPU controls and carries out all operations in the PLC. Counterfeit devices connected to a clock with a frequency between 1 to 8 MHz. This frequency determines the operating speed of the PLC and provides timing and synchronization mechanisms for all elements in the system.

The information in the PLC is transmitted by a digital signal. Internal channels which is through by digital signals called as Buss. Physically, a bus is just a passable conductor that is passable by electrical signals. This conductor could be a path on printed circuit board (PCB) or the wires in the cable.

CPU uses the data bus to send data to the PLC elements. The address bus is to send address of data storage locations. And bus control is for signals associated with internal control processes. The bus system is used for communication between the ports input / output with the unit input / output.

Beginner's Guide to PLC Programming

For a beginner who wants to learn PLC programming is strongly recommended to use a guide or tutorial. Beginner's guide to the PLC programming courses can be conducted at institutions of learning PLC programming, or you can be taught himself by reading a book or eBook PLC programming tutorials or you can also get access to an online course to let you see the PLC programming in action. You learn by watching.

Beginner's Guide to PLC Programming will learn things like the following:
• Define the most commonly used terms, such as rung, bit, input, output, etc.
• Learn relay ladder logic in simple, easy to understand terms
• Learn Machine Diagnostics and how to use them in your PLC program
• Learn the basic knowledge you need to be a top-notch PLC programmer
• Introduce to PLC control, and how it is used in plant automation

The good news is that ladder logic, and programmable logic control, is not that hard to understand. There are just a few essential concepts that you need grasp. This PLC tutorial usually explains everything you need to know to get a solid understanding of PLCs.

To the beginner, some courses or online tutorial may be more valuable than the thick and complex books written by college professors. They cover functions and algorithms you may never use. After wading through one of these, you still might not know how to turn on a motor.

Traffic Light with PLC Program

Simulation Traffic Light



Detail Traffic Light PLC Program:

Information on Drawing Numbers for Traffic Light PLC Program :
1. Red Color Lights in Position A
2. Green color lights in Position A
3. Red Color Lights in Position B
4. Green color lights in Position B
5. Red Color Lights in Position C
6. Green color lights in Position C
7. Red Color Lights in Position D
8. Green color lights in Position D


Number Of Inputs and Output PLC applied :
1. Number Of Inputs PLC is 1 Input :
--- 1 Unit Input for Switch ON/OFF Traffic Light.
--- Total Number Of Inputs PLC is Minimum 1 Input Unit.


2. Number Of Output PLC is 8 Output :
--- 1 Unit Output for Red Color Lights in Position A
--- 1 Unit Output for Green color lights in Position A
--- 1 Unit Output for Red Color Lights in Position B
--- 1 Unit Output for Green color lights in Position B
--- 1 Unit Output for Red Color Lights in Position C
--- 1 Unit Output for Green color lights in Position C
--- 1 Unit Output for Red Color Lights in Position D
--- 1 Unit Output for Green color lights in Position D
--- Total Number Of Outputs PLC is Minimum 8 Output Unit.


Sequence PLC Programming for Traffic Light PLC Program :

Step 1 :
a. If Switch ON/OFF = ON Then System Traffic Light is Active.
b. If Switch ON/OFF = OFF Then System Traffic Light is Inactive.


Step 2 :
a. IF Green color lights in Position A ( No.2) = ON then Red Color Lights in Position B,C, AND D = ON And Timer0 Activated.
b. IF Timer0 = ON then Green color lights in Position C ( No.6) = ON And Red Color Lights in Position A,B, AND D = ON And Timer1 Activated.
c. IF Timer1 = ON then Green color lights in Position D ( No.8) = ON And Red Color Lights in Position A,B, AND C = ON And Timer2 Activated.
d. IF Timer2 = ON then Green color lights in Position B ( No.4) = ON And Red Color Lights in Position A,C, AND D = ON And Timer3 Activated.
e. IF Timer3 = ON then Green color lights in Position A ( No.2) = ON And Red Color Lights in Position B,C, AND D = ON And Timer0 Activated.
f. Continuously to Step 2.b
g. Timer0,1,2,3 set to 2 minutes

Download Simulation Traffic Light :
Please Click : Traffic Light PLC Program


Can You make Program Ladder PLC ?

If Can't :

Traffic Light PLC Program with PLC Omron

Traffic Light PLC Program with PLC Mitsubishi

Traffic Light PLC Program with PLC Keyence

PLC Troubleshooting Guide

This article is only to cover the basics of PLC troubleshooting. The first step in PLC troubleshooting is to decide if the problem is internal to the processor or in the I/O system. It seems to be natural to assume that most malfunctions of PLC systems are due to processor problems. But from the experience mostly PLC malfunctions can be traced to problems with I/O modules or field equipment.

It's relatively easy to determine whether a problem is located in the processor or in the I/O system because each type of problem has a unique signature. Problems that can be localized to a specific I/O module or even a specific input or output device are usually external, while internal problems normally result in large groups of failures. Let's look first at the possible causes for internal problems.

The first thing to check is the integrity of the PLC's power and ground. Visually inspect the power and ground wiring, looking for loose, corroded, or otherwise questionable connections. The integrity of the ground can be electrically checked by measuring the voltage between the PLC ground terminal and a known ground.

Second is to check the DC supplies for AC ripple. This can be done using a digital meter set on a low AC range, and the value measured should be well below the manufacturer's specifications.

The final power check is to measure the voltage of any batteries in the system. Battery power is often used to prevent a PLC from losing its program during power outages, and battery voltages should be within recommended values.

The Systems Practice PLC

The systems practice of PLC programming is now able to simulate by using PLC control simulation software. By practicing with this software there are some advantages, they are as following:
• Practice PLC control without bulky hardware equipment.
• It provides both virtual PLC module and the virtual plant.
• User can design and simulate any system with the built-in 2D and 3D virtual plant editor.

Some specifications of PLC control simulation software as following:
• Virtual plant designing and PLC simulator for windows environment.
• Useful help system of practice examples with web browser.
• Optional hard-lock and has different authorization.
• Be able to do PLC programming practice without real PLC.
• PLC interface using PLC communication function with network card.

In the PLC control simulation software is also built-in virtual plant and virtual equipment design, simulation and monitoring. Below are the features in this software:
• Embedded virtual plants designing tool with object properties defining dialog (support Visual Basic script to establish further object properties).
• Provides frequently used objects as templates with preset properties for easy & quick virtual plant design.
• User definable Images, Objects and templates library.
• Virtual Plants can be controlled by Embedded virtual PLC
• Virtual Plants can be controlled by Real PLC
• Intuitive & Visual wiring practice between objects and PLC contacts

PLC control simulation software is suitable for people who want to practice the PLC programming with low cost. This software is called as PLC Lab Software.

Traffic Light PLC Program with PLC Omron

PLC Type Series-C Omron , Name Input / Output PLC :

INPUT PLC :
000.00 ; Switch ON/OFF Traffic Light.

OUTPUT PLC :
005.00 ; Red Color Lights in Position A.
005.01 ; Green color lights in Position A.
005.02 ; Red Color Lights in Position B.
005.03 ; Green color lights in Position B.
005.04 ; Red Color Lights in Position C.
005.05 ; Green color lights in Position C.
005.06 ; Red Color Lights in Position D.
005.07 ; Green color lights in Position D.


Please Download Picture Traffic Light PLC Program with PLC Omron :
Traffic Light PLC Program with PLC Omron


Reading Ladder PLC Programming for Traffic Light PLC Program with PLC Omron :

Step 1 :
Sequence for Green Light
a.If 000.00= ON Then System Traffic Light is Active.
Green Light in Position A = ON
b.If 000.00= ON And ( 010.00 = ON or TIM003 = ON ) And 010.02 = OFF Then 010.01 = ON ( Hold ON ) And TIM000 Activated.
Green Light in Position C = ON
c.If 000.00= ON And TIM000= ON And 010.03 = OFF Then 010.02 = ON ( Hold ON ) And TIM001 Activated.
Green Light in Position D = ON
d.If 000.00= ON And TIM001= ON And 010.04= OFF Then 010.03= ON ( Hold ON ) And TIM002 Activated.
Green Light in Position B = ON
e.If 000.00= ON And TIM002= ON And 010.01= OFF Then 010.04= ON ( Hold ON ) And TIM003 Activated.
f.If TIM003= ON And Goto Step 1.a.

Setting Timer Traffic Light = 2 minutes:


Step 2 :
Sequence for Red Light
a.If 000.00= ON And ( 010.02 = ON Or 010.03 = ON Or 010.04 = ON ) Then 010.05 = ON.
b.If 000.00= ON And ( 010.01 = ON Or 010.02 = ON Or 010.03 = ON ) Then 010.06 = ON.
c.If 000.00= ON And ( 010.01 = ON Or 010.03 = ON Or 010.04 = ON ) Then 010.07 = ON.
d.If 000.00= ON And ( 010.01 = ON Or 010.02 = ON Or 010.04 = ON ) Then 010.08 = ON.

Step 3 : Output PLC
a.If 000.00= ON And 010.05 = ON Then 005.00 = ON.
b.If 000.00= ON And 010.01 = ON Then 005.01 = ON.
c.If 000.00= ON And 010.06 = ON Then 005.02 = ON.
d.If 000.00= ON And 010.04 = ON Then 005.03 = ON.
e.If 000.00= ON And 010.07 = ON Then 005.04 = ON.
f.If 000.00= ON And 010.02 = ON Then 005.05 = ON.
g.If 000.00= ON And 010.08 = ON Then 005.06 = ON.
h.If 000.00= ON And 010.03 = ON Then 005.07 = ON.

Please Download Programming for SYSWIN :
Traffic Light PLC Program with PLC Omron

See : Traffic Light PLC Program

PLC Programming Tips

One of the tips how to do the PLC programming is making and use a “one shot”. A one shot is a coil which goes true each time the enabling rung ahead of it is true, and it stays true for one scan only, no matter how long the enabling rung is true. The one shot is useful when you have some condition that goes on and off and you want to have the PLC take action on that true state for only one scan each time the enabling rung goes from true to false.

For instant you want to count the number of times some event that lasts longer than one scan happens, but the total count will exceed the capacity of PLC built in counter. One way to deal with this problem, if your PLC has floating point registers available, is to add one to a floating point register each time the rung goes true.

A few PLC brands do not have the useful one shot feature. In this case you can make your own one shot with a few rungs of logic:

This is one of few cases in common PLC programming where the order in which you place the rungs is important. From the picture above when you start out, the input I: 3/0, the memory bit B3:0/2, and the one shot output bit B3:0/1 are all false. When the input goes true, the memory bit is still false, so the 2nd rung is true, and both memory bit and the one shot output bit are set by 2nd rung.

PLC Hardware Components

PLC consist some main components or hardware which explained as following:

1. Central Processing Unit (CPU)
PLC CPU is PLC component which function of reading and executing program instructions, may allow arithmetic operations, logic operators, block memory moves, computer interfaces, local area network, etc.

2. Memory
Memory is the storage of data in the PLC. Memory is usually inside of CPU module. The data stored in the PLC such, PLC operating system, status of input-output data memory, user-generated programs.

3. Input-Output Module
Input-Output module is the interface of the PLC to the real equipment outside. I/O module in a compact PLC usually is built-in PLC. Then a modular PLC is module I/O separate from the PLC. Generally it divided into two, Digital I/O module and Analog I/O module.

4. System Busses
System busses is the internal paths along which the flow of digital signals within the PLC.

5. Power Supply
Power supply is a source of power for the PLC. It can be an AC voltage and DC voltage. The PLC also has an internal power supply (24VDC) that can be used to provide power to the input/output devices PLC.

6. Programming Devices
Programming devices is a tool to create or edit a PLC program. It was originally a hand held programmer, the benefits of this tool is easy to bring everywhere. But this equipment difficult to use to view the entire program because the program displays are made per line.

PCs and laptops now widely used for programming a much faster and a PC / laptop are also smaller now.

Difference between RTU and PLC

PLCs use what the industry calls Ladder Logic. PLCs scan their I/O by electrically reading each I/O point. This done quickly, but in a system with lots of I/O points it can take some times to completely scan all the points.

PLCs can be used as stand alone devices but they are difficult to configure. They are not usable as the master controller in a control system. If your system contains a lot off I/O must be monitored or controlled, then PLC is not the best choice. They are not appropriate for use as protocol converters or controlling other Intelligent Electronics Devices (IEDs).

RTUs (Remote Terminal Unit) actually have the intelligent needed to control a process or multiple processes without intervention from a more intelligent controller or master. The RTU is a fast and flexible solution to most control needs. It can be used as a slave and master simultaneously in a vertical deployed control system. It is also easy to use as a protocol or for controlling IEDs.

So the main difference of PLC and RTU in application is if you need a stand alone device that has power, a PLC might work for you. But it needs to prepare some program training. PLCs can be difficult to configure.

If you need an intelligent unit to control multiple processes without intervention from a controller or master, you need a Remote Terminal Unit (RTU).

Difference between PLC and DCS

The differences between DCS and PLC are: DCS (Distributed Control System) is a CONTROL SYSTEM that works using several controllers and coordinates the work of all these controllers. Each controller is handling a separate plant. This controller is referred to the PLC.

The PLC (Programmable Logic Controller) is a CONTROLLER which can be re-program back. If the PLC is only a stand-alone and not combined with other PLCs, it is called as DDC. It means PLC is a sub system of a large system called DCS.

What’s difference between PLC and DCS by its definition:
PLC is a controller or processor that can be programmed (programmable) whose function is to run (execute) logic functions. Logic means the discrete / sequence function is usually handled by the relay. From the beginning of the vendors who carry the name of the PLC is engaged in the business discrete / sequence control.

Regardless of the distributed control system (as opposed to the DDC = Direct Digital Control) is categorized as a DCS. In DDC all system controls are done in the central processor so that if it failed, the entire control plant will also failed. DDC is mostly used as a Regulatory Control. And from the beginning vendors that carry the name of DCS is to use the product as a regulatory control.

Different in functionality means that the DCS and PLC can not be implemented on the same application.
1. DCS is not a large PLC. Because system architecture of DCS and PLC are different.
2. DCS is not PLCs that integrated into one large system. "Controller" in the PLC is more intended as a "Logic Controller", while “Controller” in the DCS is more intended as a "Process Controller".
3. Both DCS and PLC is a configurable and reconfigurable.

Difference between PLC and SCADA

To know the differences between PLC and SCADA, first we can see from the word of acronym:

PLC is Programmable Logic Controllers, a PLC is just a controller to do some works. It may be a “brick” with lots of terminals on it for wires and control something more or less by itself.

SCADA is Supervisory Control And Data Acquisition. SCADA is more complex and typically contains number of systems such as communications, data logging, server access, etc. SCADA may be used mostly by utilities and include data exchange requirement and protocols.

The difference between PLC and SCADA is also in the industry and applications.

Traditional PLC are migrating toward to traditional DCS for instants Fisher Delta V. For application in small or medium plant many people use a PLC (Allen Bradley) and also use DCS (Delta V, PlantScappe). If you have a small plant, it is better to set PLC or DCS system which has a system starting at 5 I/O and going up to 500 I/O.

SCADA is just that supervisory and data acquisition. It usually is not in plant but it used to supervise multiple small sites. In industry SCDA often do monitoring systems with little RTU at each well site.

Difference between SCADA and DCS

Talking the differences between SCADA (Supervisory Control and Data Acquisition) and DCS (Distributed Control System), they tend to involve a lot of details. Some of differences point will be described as below:

SCADA does monitoring processes across multiple sites involve the collection of data to a single location. SCADA could be described by taking “DA” portion that is “Data Acquisition. Some control usually present but not a significant amount. SCADA systems typically implement a distributed database, commonly referred to as a tag database, which contains data elements called tags or points. A point represents a single input or output value monitored or controlled by the system.

DCS is a single unit, or a group of local units. DCS system controls the process as a stand alone system. It has the control loops built into its own controller. The communication path will be through something like a LAN high speed Ethernet, or other communications network.

In data security and database maintenance you can see the differences between SCADA and DCS as below:

SCADA needs to get secure data and control over a potentially slow, unreliable communications medium, and needs to maintain a database for prompt operator display. It frequently needs to do event processing and data quality validation. Redundancy is usually handled in distributed manner.

DCS is always connected to its data source, so it does not need to maintain a database of current values. Redundancy is usually handled by parallel equipment, not by diffusion of information around a distributed database.

OPC to Provide a Standard Infrastructure of Process Control

OPC or OLE for Process Control is an industry standard for system inter-connectivity. OPC uses COM and DCOM technologies Microsoft to allow a data transfer application with one or more computers through the architecture of TCP / IP.

OPC defines a set of common interface, thus the application will retrieve the data with the same format, regardless of the data from the PLC, DCS, applications or other software. OPC is a communication solution that lives taken, installed and running.

OPC goal is to provide a standard infrastructure for data exchange control process. For example a company has a variety of data such as PLC, DCS, databases, RTU, etc. These data are available through a variety of connections, such as, serial, Ethernet or radio transmitter. While the process control applications can use a variety of operating systems such as UNIX, DOS or VMS.

OPC in this case serves to:
1. OPC standardizes process control data communication.
2. OPC standardizes the technology, not a product.
3. OPC provides true interoperability and scalability.
4. OPC can reduce implementation time and costs.

With OPC allows you to visualize, analyze, report through the application of any part with one or more OPC specifications.

By choosing the standard OPC technology, you activate the real interoperability, reduce implementation costs, and make full scalability system for the future.

Friendly Software for Beginner from Schneider PLC

PLC is widely used for process control systems in industrial automation. There are many companies that produce PLC, such as, Siemens, Omron, LG, Mitsubishi, etc. PLC price is more and more expensive now, so it becomes constraint for a beginner who wants to do experiment.

By the time we bought the PLC is usually accompanied by a CD that contains software to program the PLC. But most of the software can not be simulated. Even if the software can be simulated it needs to connect with its PLC hardware.

One of company which is Schneider Electric was producing PLC that is Zelio Logic Smart Relay. This Schneider Electric PLC has many advantages in each series. Schneider PLC is equipped with software to program the PLC the name is ZelioSoft

There are a lot of features in ZelioSoft, The standard features such as Digital Input, Digital Output, Timer, Counter, Analog Comparator, and Auxiliary contact. And more importantly ZelioSoft can be simulated without associated with its PLC hardware. This is very helpful to beginners if you want to learn PLC.

In addition to the hardware can be simulated without a PLC, ZelioSoft can also be programmed in the format:
1. Ladder symbol, this allows programmers who prefer programming with Ladder easier to do in this format.
2. Electrical symbol, this will allow programmers who prefer electrical wiring diagrams.
3. Functional Block Diagram, this will facilitate programmers who familiar with logic gates.

Below are sample images of Schneider ZelioSoft program:

Basic Instructions of PLC Omron

In this article will discuss the basic instructions Omron PLC. The instructions as below:
1.LOAD (LD), this instruction is used when a work order control system requires only one logic state. This is similar to the NO relay contacts. The symbol is:

2.LOAD NOT, this command is used when a work order control system requires only one logic condition. This is similar to NC relay contacts. The symbol is:

And below are the instructions that are used when the work order control system requires more than one condition and all conditions must be met to produce a single output. The instructions are as follows:
3. AND, the symbol is:

4.AND NOT, the symbol is:

5.OR, the symbol is:

6.OR NOT, the symbol is:

7.OUT, this instruction is used to generate a logic output when the conditions are met. The symbol is:

8.NOT OUT, this instruction is used to generate a logic output when the conditions are met. The symbol is:

9.TIMER (TIM) and COUNTER (CNT), the PLC which amounted to 512 numbers from TC 000 to TC 511. Value of Timer / Counter is counting backwards from the initial value. After reaching zero then contact Timer / Counter will be ON.
The Timer symbol is:

The timer is active when the execution condition is ON and reset when OFF. TIM executed first in order to measure SV 0.1 seconds.
The Counter symbol is:

10.COMPARE-CMP (20), Comparing Cp1 with Cp2 and outputs the results is GR, EQ with the LE flag in the SR area.

11. DIFU (13) Differentiate UP, DIFU (13) makes marked bits ON (0) one cycle when switched from OFF state to ON (leading edge).

12. DIFD (14) Differentiate Down, Turn ON bit (0) one cycle when the condition is switched from ON to OFF.

13. ADD (30) BCD Add, Adding the contents of Au, Ad and Cy, the result is placed in R.

14.SUB (31) BCD subtract, subtracts the contents of Su and CY from Mi and places the result in R. If the result is negative, CY is set and the 10's complement of the actual result is placed in R. To convert the 10's complement to the true result, subtract the contents of R from zero.

SCADA Controls the Complex Systems in Real Time

If you work in an environment that requires power supply, a controlled temperature, humidity, stable environment and all the equipment operating continuously. Or you need to know in real-time status of various components and equipment in a complex system. Or you work at many more similar working conditions.

One effective way to control all the above work is to implement SCADA system at your workplace. Why should SCADA? Because SCADA systems could do the things below:

1. Accessing the quantitative measurement to the key processes directly and at all the time.
2. Detect and correct the errors quickly.
3. Measure and monitor the trends over time.
4. Finding and eliminating bottlenecks and waste times.
5. Control the larger Processes and more complex with less of people.



So SCADA systems provides ease of set up and configure a system by placing sensors and control systems at each critical process. More and more sensors are placed at each process, so that more detailed operations that can be monitored. And it can work in real time.

Although the operation processes in large-scale and highly complex, SCADA systems are able to scan if something goes wrong, other than that SCADA can improve efficiency so that you can do many things with cheaper cost and will certainly increase the profit.

Below is an example of architecture SCADA:

PLC Programming for Industrial Automation

To improve production, quality, and risk, industries need to implement industrial automation. The most popular in industrial automation is automation system with PLC programming.

There are a lot of PLC application in industrial, such as industrial automation, system control of the packing of goods conveyor, water treatment, system control of automatic loading machine, recondition control panel, system control of air conditioner and chiller, and many more.

Industrial automation with PLC programming will bring in value to the industry. For instant in warehouse planning & automation it will determine the cost of material movement and storage, such as how much space is truly required? Are the transport distances in the warehouse optimized? Etc.

It also can evaluate and quantify the expenditures of labor, such as value-added and non-value added, repetitive motions, inefficient handling. And it can evaluate throughput and production levels in receiving, storage, order picking, manifest and shipping.

Industrial automation above can be controlled by industrial control system which is called as Supervisory Control and Data Acquisition (SCADA). A SCADA system consists of the following sub systems:
-> A Human Machine Interface or HMI is the apparatus which presents process data to a human operator.
-> A Supervisory (computer) system, acquiring the data and send command to the process.
-> Remote Terminal Units (RTUs) connecting to sensors in the process and sending digital data to the supervisory system.
-> Programmable Logic Controllers (PLCs) used as field devices.

Traffic Light PLC Program with PLC Mitsubishi

PLC Type FX-Mitsubishi , Name Input / Output PLC :

INPUT PLC :
X000 ; Switch ON/OFF Traffic Light.

OUTPUT PLC :
Y000 ; Red Color Lights in Position A.
Y001 ; Green color lights in Position A.
Y002 ; Red Color Lights in Position B.
Y003 ; Green color lights in Position B.
Y004 ; Red Color Lights in Position C.
Y005 ; Green color lights in Position C.
Y006 ; Red Color Lights in Position D.
Y007 ; Green color lights in Position D.


Please Download Picture Traffic Light PLC Program with PLC Mitsubishi :
Traffic Light PLC Program with PLC Mitsubishi


Reading Ladder PLC Programming for Traffic Light PLC Program with PLC Mitsubishi :

Step 1 :
Sequence for Green Light
a.If X000= ON Then System Traffic Light is Active.
Green Light in Position A = ON
b.If X000= ON And ( M0 = ON or T3 = ON ) And M2 = OFF Then M1 = ON ( Hold ON ) And T0 Activated.
Green Light in Position C = ON
c.If X000= ON And T0= ON And M3 = OFF Then M2 = ON ( Hold ON ) And T1 Activated.
Green Light in Position D = ON
d.If X000= ON And T1= ON And M4= OFF Then M3= ON ( Hold ON ) And T2 Activated.
Green Light in Position B = ON
e.If X000= ON And T2= ON And M1= OFF Then M4= ON ( Hold ON ) And T3 Activated.
f.If T3= ON And Goto Step 1.a.

Setting Timer Traffic Light = 2 minutes:


Step 2 :
Sequence for Red Light
a.If X000= ON And ( M2 = ON Or M3 = ON Or M4 = ON ) Then M5 = ON.
b.If X000= ON And ( M1 = ON Or M2 = ON Or M3 = ON ) Then M6 = ON.
c.If X000= ON And ( M1 = ON Or M3 = ON Or M4 = ON ) Then M7 = ON.
d.If X000= ON And ( M1 = ON Or M2 = ON Or M4 = ON ) Then M8 = ON.

Step 3 : Output PLC
a.If X000= ON And M5 = ON Then Y000 = ON.
b.If X000= ON And M1 = ON Then Y001 = ON.
c.If X000= ON And M6 = ON Then Y002 = ON.
d.If X000= ON And M4 = ON Then Y003 = ON.
e.If X000= ON And M7 = ON Then Y004 = ON.
f.If X000= ON And M2 = ON Then Y005 = ON.
g.If X000= ON And M8 = ON Then Y006 = ON.
h.If X000= ON And M3 = ON Then Y007 = ON.

Please Download Programming for GX Developer :
Traffic Light PLC Program with PLC Mitsubishi

See : Traffic Light PLC Program

Implementation SCADA in Industry and Infrastructure Projects

SCADA or Supervisory Control and Data Acquisition have two elements in the application, namely:

1. Processes, systems, machines that will be monitored and controlled. The examples are power plants, irrigation systems, computer networks, etc.

2. An intelligent network interface to the system via external sensors and control. With SCADA network capable to control and monitor components in the system.


SCADA is used to make industrial processes and complex infrastructure working automatically. SCADA applications as followings:

a. Producing electricity, electricity transmission and distribution. SCADA functions as a detector size of the current and voltage, circuit breaker monitoring operations, and switch ON / OFF the power grid.

b. Reservoirs and water distribution. SCADA functions as monitoring of water flow rates, reservoir elevation, pressure pipes, etc.

c. Buildings, facilities and environment. SCADA functions as HVAC controllers, cooling units, lighting control and security systems.

d. Production. SCADA functions as a regulator of components inventory, machine or robotic automation, monitoring and quality control processes.

e. Railway transportations. SCADA functions as the controller electric power distribution, automation railway traffic signals, track and find the location of the train.

f. Traffic lights. SCADA functions as a regulator of traffic lights control the speed of traffic and detect the wrong signal.


SCADA is currently applied in many industrial and public infrastructure projects. All applications that require ease of monitoring and control, with various media interfaces can be treated with SCADA implementation.

PLC Based Industrial Automation

Automation plays an increasingly important role in the world economy and in daily experience. In the scope of industrialization, automation is a step beyond mechanization. Whereas mechanization provided human operators with machinery to assist them with the muscular requirements of work, automation greatly reduces the need for human sensory and mental requirements as well. Processes and systems can also be automated.

A well industrial automation does not need human supervision over equipment and process operation. It will eliminate possible human errors and staff training due to staff turnover. The industrial automation based on PLC becomes very accurate, yielding consistent product quality and material usage.

Programmable Logic Controllers (PLCs) have been around forever in technological term. Their proven reliability in harsh environment together with their ability to handle multiple inputs and outputs has made them the corner stone in the majority of modern day industrial control systems.

Industrial automation based PLC can be combine with most other technologies to provide a sophisticated control and monitoring solution. It is reassuring to know that the PLC is one less thing to worry.

The advantages of industrial automation are:
1. Replacing human operators in tasks that involve hard physical work.
2. Making tasks that are beyond the human capabilities such as handling too heavy loads, too large objects, too hot or too cold substances, etc.
3. Replacing humans in tasks that should be done in dangerous environment.

Tutorial Ladder Diagram via State Diagram

PLC control system development through ladder diagram basically just used for modernizing of electromechanical relay control systems into the form of software.

For a new project, the representation of the control system through ladder diagram certainly will be very difficult to obtain (except for cases of automation or a simple control system).

To overcome this, a designer of control systems must be able to represent his ideas into the form of images relatively easy to understand. What is suitable for these cases? The answer is a State Diagram.

In this tutorial will illustrate how to build a model state diagram for a control system. An example is the flip-flop,



Specification of the system work very simple: Every 0.5 seconds, the situation will change lights alternately.

Now we represent the system through state diagrams. For this case the system obviously has only two states, see the image above. The system will transition every 0.5 seconds delay, the transition state in this case, of course, triggered by a timer (e.g. timer On Delay). A complete state diagram for the case you can see in the picture below.



From the picture above to know how to transform the state diagram into its equivalent ladder form:

When the PLC is first turned on, then the instructions will be executed PLC initialization (only once), then, by using instruction blocks if... then, we implement the control logic through instruction MCR (Master Control Relay). See details at the picture below.

Learn PLC Programming

To learn PLC programming you must have a background in creating ladder diagram of control engine. Because the basic level of PLC ladder is equal the control engine ladder diagram.

When learning PLC programming, the difficult concept is to understand the difference between the physical component and the component programs. We will connect physical components (switches, lights, Relays, etc) to the terminal outside the PLC. Then, all components connected to the PLC will be represented on the program as program components.

PLC programming can be seen from the picture below, circuit diagrams AND ladder consists of two push button switch connected in series with the lamp.



When we want to change the circuit in order to run the PLC, then the first time we need to remove all components and wiring back to the PLC system as shown below.



From the picture above we can see the obvious differences is both switches not connected in series but they connected into a separate component on the PLC input.

In other words we can make the circuit wire into the desired software. Two 120 V source in fact is the same, but the images are shown separately to be easy to see how the inputs and outputs are connected to the PLC and how each part is getting power.

After knowing the external components connected to the PLC, we can write the program. Switch1 connected to IN1 is called IN1 on the program, and Switch 2 connected to IN2 is called IN2 on the program. For Lamp1 that connected to OUT1 is called OUT1 on the program. Above program is to control the Lamp1 as shown in the following figure:

Programming PLCs Using Rockwell Automation Controllers

Rockwell Automation is a global provider of industrial automation, power, control and information solutions. The brands of Rockwell automation industrial automation are Allen-Bradley and Rockwell Software.

Programmable logic controllers (PLC) programming that using Rockwell automation, actually is using Allen-Bradley brand. Application of programmable logic controllers from Rockwell automation in industrial automation as following:

Automotive Industries
By using PLC programming from Rockwell automation you get accurate, event driven information about materials, operation and finished product requirements.

Fibre and Textiles Industries
It can improve the process in this field, such as, deploying flexible manufacturing strategies so that you can manufacture multiple products in single machine. Increasing uptime of continuous processes. Providing automatic ability for tracking and tracing for safety, etc.

Intelligent Motor Control
By using Rockwell automation you can optimize motor performance through network control and protection. Minimized start up times. Reducing downtime and simplified troubleshooting, etc.

Metal forming Industry
It can help to reduce cost, system development time, and installation time. To increase system flexibility and operation. To reduce the risk through the use of standard software modules and field proven design, etc.

Material Handling and Logistic Industry
Rockwell automation can improve your customer's operation by finding the optimum configuration of equipment and information technology for an effective material-handling system.

PLC Simulator For Learn PLC Programming

To study the PLC programming can be done by using a PLC simulator on the internet.



There are many PLC simulator on the Internet, they are:

1. Trilogi (http://www.tri-plc.com/trilogi.htm)
This trilogi is a PLC simulator software which has a complete and comprehensive. In this software there are basic instructions, such as the contact and coil, timers and counters. There are also advanced instructions such sequencer to a custom function that can be made with Tbasic language.

2. PSIM (http://www.thelearningpit.com/plc/psim/psim.html)
PSIM is a software simulator PLC that is old enough, because it is still based on DOS. This software is used specifically for the Allen Bradley PLC. To study the Allen Bradley PLC would be very suitable when using this software because of the extra software is to display the exercises with a graphical interface for the application of water filling, mixing and light traffic.

3. Andrea Barbossa (http://www.andrebarbosa.eti.br/SimuPLC Eng/DownLoad_Eng.htm)
From the display looks this software quite interesting. And you do not require registration to download this software.

4. PLC Simulator (http://www.plcsimulator.net)
If you want to use this PLC simulator, it should be online. Because the PLC simulator is connected to the internet.

With this simulator PLC will make it easier for beginners who want to learn PLC programming. In addition those software are special designed for PLC programming, there are also examples to practice programming the PLC.

Simatic S5 PLC System Automation from Siemens

Simatic S5 PLC is automation system based programmable logic controllers (PLCs). This product is manufactured by Siemens. This automation system is widely used in machinery and equipment control systems. Actually Simatic S5 PLC product is obsoleted. This product has been replaced by a new generation of Simatic S7 PLC.

However Simatic S5 PLC has many installed in most factories and companies around the world. So that the product of S5 PLC is still available to support these industries.

Products from S5 PLC are available in various chassis styles such as, 90U, 95U, 101U, 100U, 115U, 135U, and 155U. The increasing numbers of this model is more expensive.

The S5 product line usually is programming with PC-based software programming tool called Step 5. Step 5 is used for programming, testing, commissioning and documentation for the program Step 5.

Original version of this Step 5 ran on CPM operating system version. The next version ran on MS-DOS. And then version of Windows XP-based. And the final Step 5 version 7.2.

Siemens also took a proprietary state logic programming, called Graph 5. Graph5 is a sequential programming language intended to be used on machines that operate through a series of discrete steps.

Step5 allows to create a simple operations AND / OR program up to complex subroutines. Step5 structure offers a number of facilities:
a. Block Technique, a linear sequence of operations which is divided into sections and packed into the individual block.
b. Segments, within the block, fine-structuring allows for programming subtask in the segment.
c. Comments - Both a complete program as well as individual blocks or segments and the individual statements can be directly provided with comments.

Step5 program can be represented in 3 different ways:
1. Statement List (STL), the program consists of the command mnemonic code which is executed by the PLC.
2. Ladder diagram (LAD), automation system which is represented by a row of charts and symbol circuit diagram.
3. Function Block Diagram (FBD), graphical representation of the automation tasks with symbols to DIN 40700 / DIN 40,719.

There are 5 block diagram available in Step5:
1. Organization blocks (OB) - for managing the control program.
2. Programming blocks (PB) - contain the control program structured according to functional or process-oriented characteristics.
3. Sequence blocks (SB) - for programming sequential controls.
4. Function blocks (FB) - contain frequently occurring and particularly complex parts program.
5. Data blocks (DB) - for storing data required for processing the control program.

Step5 has three distinct operations, namely:
a. Basic operations, including the linking, saving, loading & transferring, counting, Comparing, arithmetic operations, module operations.
b. Supplementary Operating and complex functions, including the substitution statements, testing functions, word-by-word logic operations, decrement / increment and jump functions.
c. System operations, direct access to operating systems.

Industrial Automation Using PLC

In today's world of industry, where technological developments to support the production process for accuracy, speed and quality as expected and meet the market standard, the technology of production machines nearly all been equipped with the system control / drive in either electronic instrument panel and the drive such as touch screen panel for monitoring panels, Inverters, DC drives, Servo drives and PLC Programmable Logic Controller.

Mostly in automation industries use programmable logic controllers (PLCs). In the industrial automation systems that support it include:

1. Inverter / AC Drive, it is a device used to control a motor cycle production machines.

2. Dc Drive, it consists of an SCR (Silicon Controlled Rectifier) bridge, which converts the incoming three-phase or single AC volts to DC volts. During this conversion process the DC drives can then regulate speed, torque, voltage and current conditions of the DC motor.

3. Servo Drive, it can be used in CNC machining, factory automation, and robotics, among other uses. Their main advantages of DC or AC motors are the addition of the motor feedback. This feedback can be used to detect unwanted motion, or to ensure the accuracy of the commanded motion.

4. PLC Programmable Logic Controller as programmed control system using software to control automation system.

5. Switching power supply

PLC Automation Systems

PLC automation system is a technology related to mechanical application, electronic and system which is based programmable logic controllers (PLCs). With the industry growing, PLC automation system is needed to support the smooth running of each process in the industrialized field, and replacing conventional automation systems that are outdated.

The impact of using systems automation PLC is increasing productivity and higher quality.

The basic elements of automation system

There are three basic elements on which the absolute requirement for automation systems, namely:

1. Power also called as energy source of the automation system. This serves to move all the components of the automation system. This power could be electric energy, battery or Accumulator.

2. Program of Instruction. The process of automation control system is absolutely needed. For this instruction program is a PLC programming system is very important role in controlling an automation system.

3. Control System. This is the most important part of an automation system. The analogy with the human body then this control system is part of the brain that regulated movement of the whole body. This control system consists of electronic circuits is controlled by the PLC programming software that controls the entire system. Example PLC automation system is a robot assembly that implement in the industry and the movement of the robot is controlled by the PLC programming.

Traffic Light PLC Program with PLC Keyence

PLC Type KV Keyence , Name Input / Output PLC :

INPUT PLC :
0000 ; Switch ON/OFF Traffic Light.

OUTPUT PLC :
0500 ; Red Color Lights in Position A.
0501 ; Green color lights in Position A.
0502 ; Red Color Lights in Position B.
0503 ; Green color lights in Position B.
0504 ; Red Color Lights in Position C.
0505 ; Green color lights in Position C.
0506 ; Red Color Lights in Position D.
0507 ; Green color lights in Position D.


Please Download Picture Traffic Light PLC Program with PLC Keyence :

Traffic Light PLC Program with PLC Keyence


Reading Ladder PLC Programming for Traffic Light PLC Program with PLC Keyence :

Step 1 :
Sequence for Green Light
a.If 0000= ON Then System Traffic Light is Active.
Green Light in Position A = ON
b.If 0000= ON And ( 1000 = ON or T003 = ON ) And 1002 = OFF Then 1001 = ON ( Hold ON ) And T000 Activated.
Green Light in Position C = ON
c.If 0000= ON And T000= ON And 1003 = OFF Then 1002 = ON ( Hold ON ) And T001 Activated.
Green Light in Position D = ON
d.If 0000= ON And T001= ON And 1004= OFF Then 1003= ON ( Hold ON ) And T002 Activated.
Green Light in Position B = ON
e.If 0000= ON And T002= ON And 1001= OFF Then 1004= ON ( Hold ON ) And T003 Activated.
f.If T003= ON And Goto Step 1.a.

Setting Timer Traffic Light = 2 minutes:

Step 2 :
Sequence for Red Light
a.If 0000= ON And ( 1002 = ON Or 1003 = ON Or 1004 = ON ) Then 1005 = ON.
b.If 0000= ON And ( 1001 = ON Or 1002 = ON Or 1003 = ON ) Then 1006 = ON.
c.If 0000= ON And ( 1001 = ON Or 1003 = ON Or 1004 = ON ) Then 1007 = ON.
d.If 0000= ON And ( 1001 = ON Or 1002 = ON Or 1004 = ON ) Then 1008 = ON.

Step 3 : Output PLC
a.If 0000= ON And 1005 = ON Then 0500 = ON.
b.If 0000= ON And 1001 = ON Then 0501 = ON.
c.If 0000= ON And 1006 = ON Then 0502 = ON.
d.If 0000= ON And 1004 = ON Then 0503 = ON.
e.If 0000= ON And 1007 = ON Then 0504 = ON.
f.If 0000= ON And 1002 = ON Then 0505 = ON.
g.If 0000= ON And 1008 = ON Then 0506 = ON.
h.If 0000= ON And 1003 = ON Then 0507 = ON.

Please Download Programming for KV Builder :
Traffic Light PLC Program with PLC Keyencee

See : Traffic Light PLC Program

Basics of PLC Programming

What is a PLC?

The National Electrical Manufacturers Association (NEMA) defines a PLC as a "digitally operating electronic apparatus which uses a programmable memory for the internal storage of instructions by implementing specific functions, such as logic, sequencing, timing, counting, and arithmetic to control through digital or analog I/O modules various types of machines or processes."

To understand how PLC working, you need to understand the working principles of relay, a relay has a coil which is supplied by a voltage source and it is connected to two terminals.

The principle of the relay: while connected to voltage source then all contacts will change their status. NO means contacts ‘close’ and NC means contacts ‘open’.

The principle of PLC signal is the device input (on/off) will activate the coils. All inputs are reflecting each input device. (In this case, it is stored in a memory data input) coil will control all of these conditions on / off internal contacts that arranged in a program PLC / ladder diagram (programming & processing).

What's it look like?

PLCs come in various sizes. Generally, the space or size that a PLC occupies is in direct relation to the user systems and input/output requirements as well as the chosen manufacturer's design/packaging capabilities.

The chassis of a PLC may be of the open or enclosed type. The individual modules plug into the back plane of the chassis.

The electronic components are mounted on printed circuit boards (PCBs) that are contained within a module.

History of Programmable Logic Controllers

The PLC was invented in response to the needs of the American automotive manufacturing industry. Programmable controllers were initially adopted by the automotive industry where software revision replaced the re-wiring of hard-wired control panels when production models changed.

PLC was first introduced in the 1960s. The PLC is made to reduce the burden of maintenance and replacement of engine control systems that use relays. Bedford Associates proposed MODICON (Modular Digital Controller) for companies in America. MODICON PLC 084 is first used in commercial production.

Increasing number of needs in the production process causes the system should be modified. If the system used a mechanical relay, of course it will be a big problem. Beside that its use limited period, the system also requires a careful treatment. If there is damage it will be very difficult to find. That is why control is needed that allows both the maintenance and application.

In the 70s, the dominant PLC technology is the machine and sequencer-based CPU bit-slice. AMD 2901 and 2903 are popular and used in PLC MODICON AB. communication skills in PLC emerged in early 1973. The first system is Modbus from MODICON.

In the 1980s an attempt was made to standardize communications with General Motor's protocol (MAP). In the 1990s carried out a new protocol reduction and modernization of the physical layer protocols are popular in the 1980s. The final standard was IEC 1131-3, trying to combine the PLC programming languages under a single standard.

Fundamentals of Programmable logic Controllers

Programmable Logic Controllers (PLC) is an electronic computer is easy to use (user friendly) which has control functions for various types and levels of various difficulties.

Definition Programmable Logic Controller according to Capiel (1982) are electronic systems that operate in the digital and designed to use in industrial environments, where the system uses a programmable memory for internal storage of instructions that implement with specific functions such as logic, sequence, timing, enumeration and arithmetic operations to control the engine or process through the modules I / O digital and analog.

The National Electrical Manufacturers Association (NEMA) defines a PLC as a "Digitally operating electronic apparatus which uses a programmable memory for the internal storage of instructions by implementing specific functions, such as logic, sequencing, timing, counting, and arithmetic to control through digital or analog I / O modules various types of machines or processes."

PLC is designed to replace a circuit relay sequential in a control system. Beside it can be programmable; this tool can also be controlled, and operated by people who do not have knowledge in computer operation. This PLC has a programming language easily, understandable and can be operated when the program was created by using the software according to the type of PLC used is entered.

Brief Information about PLC

Talking about PLC is obviously talking about the development of technology. As a matter of fact, it has something to do with its history and the development of technology. However, due to the complicated and rambling information about PLC available and presented in sites and blogs, people are quite hesitant to read them. Hence, this passage presents some brief explanation and information about PLC: its history and how it works.

Indeed, knowing about PLC working system is quite a problem to certain numbers of people. Here is the brief explanation. PLC is a kind of digital electronic device with programmable memories used to keep and maintain special instructions that control specific functions, such as logics, sequences, timings, and other essential functions.

Before PLC period, all of production systems in all fields of industries were done by so-called ‘relay’. As the demand of electronic devices increased, this relay-based machine control system was somewhat inefficient, that industrialists were trying to find the replacement tool. At that time, one company that seemed to be eager in finding the replacement tool is the General Motors; in 1968, the biggest vehicle manufacturer in the United States, requested some electronic companies to make them this replacement system. The Bradford Associates – which later changed its name into Modicon Corporation – won the proposal. One of the Modicon founder, Dick Morley, was the first person who introduced PLC (Programmable Logic Controller) to General Motors and a big electronic company named Gould Electronics. Interested to know more about PLC and its effects to the production, GM then purchased the first product that was coded 084.

After the first PLC, industrialists and scientists seemed to be interested about PLC that they were competing in developing it for it is much more efficient than relay. Using relay-based machines, they needed lots of money to gain their production. While using PLC, they do not need to spend much money in production upgrading.

Just an additional information why people should know about PLC early and modern programming system: in relation to the programming system, PLCs in the past are somewhat different from PLC at present. Early PLCs’ programming used a kind of instruction list, which was based on a stack-based logic solver. While modern PLC is programmed in various ways, even to such traditional programming languages.

If you wish to learn more about PLC, simply access your internet and search for the particular issue. Within only seconds, you will find myriad information on it and every single thing related to it to qualify your need. Take your time and be well-informed on this matter.