Generally, PACs and PLCs do the similar function. Both are principally utilized to do process control, automation, and functions of data acquisition for example, the control of digital and analog, motion control, serial handling of string, machine vision, and PID. The parameters within which PACs work to reach this, though, sometimes operate counter to how a functions of PLC.
ARC classified five main characteristics of PAC:
• Tools of software that enable the design by flow of process across some process units or machines.
• Multi domain functionality, at least two of logic, drives, PID control, motion, and on a single platform process
• Single multi discipline in development platform integrating to a common tagging and an access single database to all functions and parameters
• Open modular architectures that mirror industry applications
• De facto standards employment for languages, network interfaces, etc., for example SQL queries, XML and OPC, and TCP/IP
The hardware of PAC goals are built for applications requiring:
• Capabilities of Processing – NI PACs do extremely well in applications where particular advanced signal processing, data logging, or control algorithms is needed. You can integrate the code of custom control built with NI or third-party devices, apply signal processing using LabVIEW.
• Graphics – Half of the tools and features consisted of in LabVIEW are created to make simpler user interfaces development. As such, you can simply integrate HMI and graphics for control systems.
• Communication -- LabVIEW creates it simple for you to transfer data to the project with tools such as SQL/ODBC and OPC
• Measurements -- National Instruments has a strong expertise I/O in high-speed, including acquisition of vision, then you can integrate measurements such as machine vision or vibration into the control systems standard.
• Platforms -- you can make code that works various platforms including a FPGA chip, handheld PDA, PC, or embedded controller using LabVIEW.
Not like PLCs, PACs present open modular architectures, the motivation being that because mainly industrial applications are made to order, the hardware control utilized for their requirements to let engineers to pick and select the other components in the architecture of control system without worry whether they will be well-matched or not with the controller.
In programming PACs and PLCs are also differently. PLCs are frequently programmed in a graphical programming language, ladder logic, and ladders rungs that is created to emulate old wiring diagrams of electrical relay. The control programs of PAC are typically created with more generic software tools that allow the designed program to be distributed across some different processors, HMI terminals, machines, or other components in the architecture of control system.