Schneider PLC

These are controlled by the SCHNDR iocs and are used on various instruments, such as to monitor value status or pressure (a TPG300 can for example feed data into the PLC inputs). Communication is by modbus protocol using EPICS modbus support.

Relevant IOC config macros are:

• MODE: TCP, RTU or ASCII to specify PLC connection mode. We generally use either TCP or RTU.
• PORT: Serial COM Port of PLC for RTU or ASCII mode
• IPADDR: IP address of PLC for TCP mode
• IPPORT: TCP will connect on default modbus 502 port, set this if different.

To configure EPICS records for PLC specific variables, set macros such as DEVCMD1 to a CMD file base name in the devices subdirectory which should be loaded. For example on GEM we set DEVCMD1 to GEMGateValve to load devices/GEMGateValve.cmd. Currently there is only DEVCMD1 but if there were cross instrument files that were useful to load, or a plc talked to multiple separate devices, then adding DEVCMD2 may be useful in future

PLC IOC files