Few Choices exist in when designing a PFI PLC System. This is done to eliminate the need to diversify our parts stock and our understanding of too many types of systems. Allen Bradley is the PLC of choice for many reasons. Within the current offerings of AB we have the following choices:
1. ControlLogix
2. CompactLogix
3. FlexLogix (no longer available as a controller)
Defining the Task and Size of the process will determine the PLC that should be used. For example, a Process with 5 motors, 2 temperatures, 4 level probes that will have an HMI and generate reports would use which Options?
Option 1, ControlLogix is a valid choice. but may be overkill. Other requirements of the process might justify the overkill. If project can bear cost, no other consideration need be looked at. Currently as of 2018 we are using L83e with version 30.11. We do not allow PLC's with any version of 20 - 23. Some packaging machines are on Version 24. But we prefer to use version 30. Any L6x series is on version 19 only.
Option 2, CompactLogix is a valid choice. If extreme physical conditions or size and complexity exits it would be a poor choice. We no longer use L32e or L35e...
Networks required will play a large part in determining which PLC is selected. See individual subpages for more detail.
1. Ethernet - Always suggested, is required for HMI and Remote Programming
2. Ethernet I/P - Required if Remote I/O panels are needed and/or AB MCC with Devicenet are present.
3. Devicenet - Used to control and monitor IEC motors using E3+, PowerFlex Drives, and/or SMC Flex SoftStarts. Only when local or low density motor control is required.( After 15 to 20 motors are required a MCC would be purchased).
4. Other Networks exist, such as Modbus, Profibus, Bacnet, Wireless... These are special circumstances and should be approached carefully.