What is Programmable Automation Controller? (PAC)
Ø PAC is a compact controller which combines the features of Process control, Motion Control, Data Acquisition along with PLC.
Ø Up to 2 Lakh I/O’s can be supported.
Ø Replacement of DCS (Distributed Control System), which involves huge size & complexity.
What are the Features of Programmable Automation Controller? (PAC)
Ø Multifunction
Ø Multidomain
Ø Open communication standards
Ø Multitasking
Ø Modular Architecture
Ø Multi-vendor data exchange
Ø Integrated development environment
We will now see each feature separately……………
Multifunctional:
Ø Digital, analog and serial types of signals are common in every industrial application. PAC’s can handle all these signals at once.
Ø PAC’s handles many functions simultaneously, from changing simple on/off states, to complex PID calculations for temperature control, gathering data from digital components like RFID tags etc.,
Multidomain:
Ø PAC’s can connect to different levels of domains from remote monitoring and data acquisition, process controls like chemical industries, and all kind of manufacturing industries.
Ø Simple software use, makes it easy to customize PACs for your own needs and requirements.
Open communication standards
Ø PAC’s uses standard IT components and protocols, makes it easier integration and low implementation costs.
Ø Components like inexpensive Ethernet hardware a common communication device for networking and well understood protocols like IP, TCP, SMTP, FTP, UDP, SNMP which are already used by computers.
Multitasking
Ø PAC’s can handle different types of tasks simultaneously like, controlling processes, independently reading and writing to system variables and devices.
Ø A PAC can communicate with multiple clients using standard communication protocols.
Modular Architecture
Ø PAC modularity places intelligence where it’s needed distributed throughout the system.
Ø Distributed processing means that counting and PID loops, for example, operate independently on I/O units, leaving the main controller free to oversee the system.
Ø With flexible modular design, you can add or change distributed units easily. Because the software code always refers to logical representations of I/O points, the physical location of points can be changed without disturbing the programming code.
Multi-Vendor Data Exchange
Ø PACs ability to exchange data with other vendors’ hardware and software means lower integration costs.
Ø Data exchange using OLE for process control (OPC), for example, makes it easy to read and write to I/O points and variables the PAC is managing.
Integrated Development Environment
Ø The fully integrated software used with PACs lowers project development and maintenance cost.
Ø A single tagname database is automatically created when you build the programming logic.
Ø Once created, it is immediately available for developing operator interfaces and for moving data to OPC clients.
Ø Flowchart-based design and English-syntax commands also make development and maintenance easier.
PACs vs. PLCs
PAC
Ø Standard, commercial hardware
Ø Diverse protocols and open standards
Ø Foundation of logic: exception based
Ø Distributed processing
Ø Common tag database
Ø Multitasking
PLC
Ø Proprietary network, communication, and programming
Ø Programming and function are modeled after relay circuits
Ø Ladder logic foundation
Ø Continuous scanning
Ø Mandatory duplication of data tags for interoperability
