Programmable Automation Controllers (PACs) – Features & Applications

What are Programmable Automation Controllers?

Programmable automation controllers (PACs) are process controllers with an open configuration and possessing the enterprise integration power of a PC-based structure. In other words, PACs are industrial controllers that combine the functionality of a programmable logic controller (PLC) with the processing capability of a PC.

Basic Features of Programmable Automation Controllers

Programmable automation controllers (PACs) possess the following features:

• They are digital computers that hold and execute embedded programs.
• They are multiprocessor devices in-built with two or more processors that provide multitasking capabilities to control automation of different parts of equipment.
• PACs have advanced capabilities in-built in their designs, for example, they are capable of performing certain important tasks like data acquisition, latching, loop control.
• Their modular design and open architecture makes it possible for the PACs to operate with Human Machine Interface (HMI), Other PACs, PLCs, etc. They can communicate with other networks through Fieldbus, Ethernet, and other compatible industrial networks. Additionally, the modular design permits the adding and removal of these communication ports as well as allowing the control and data acquisition from many input and output outlets.
• They are compact, customizable and high performance process controllers for industrial automation.

Applications of Programmable Automation Controllers (PACs)

• Large industrial applications usually require more processor power and memory than what a basic PLC package would deliver. PACs contain all the capabilities of the PLC systems in addition to other powerful and advanced features hence making them the best fit for such kind of applications.
• PACs are typically designed for much larger distributed control like discrete manufacturing control systems. Their instruction sets are more advanced and powerful requiring the enhanced capabilities of a programmable automation controller which enable them to meet the requirements of these large industrial applications. Additionally, the instructions sets are built with a certain objective such as, sequencing, batching, etc.
• The PC-based software enables PACs to handle complex automation projects.
• PACs are typically used with enterprise-level supervisory control and data acquisition (SCADA) systems for plant wide control and data collection.
• PACs have evolved, and presently they are capable of advanced control, accomplishing the same purpose traditionally reserved for DCS systems.

Reasons to Consider PACs in Your Automation Plans

PACs possess certain capabilities that make them the top pick for industrial automation, for example:

• They have an open architecture making it possible to connect them to any device.
• They possess extensive analog control capabilities.
• They are inexpensive to maintain compared to PC-based control.
• PACs can run in a scheduled cyclic mode.
• PACs have more connectivity options.

Comparison of PLCs with PACs

• PLCs are typically employed in simple and high speed machine control applications. For example PLCs are used in original equipment manufacturers (OEM) machines such as fillers, packers, palletizers and small process skids. On the other hand, PACs are ideal for large-scale automation projects and operations.
• PLC is a single microprocessor device which is used to control manufacturing processes, machine control, etc. on the other hand, PAC is a multiprocessor device which is built with two or more number of processors like a PC. PACs are capable of controlling various parts of equipment.
• PLC has in-built networks which enable it to communicate with multiple PLCs, inputs/outputs, HMIs, as well as SCADA systems whereas PAC is integrated with modular design, open architecture used for communicating, monitoring and controlling apparatus covering multiple networks and devices.

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