Automated Checking and Visualization of Interlocks in the ISAC Control System
The EPICS based control system of the ISAC radioactive beam facility supervises several sub-systems, which are controlled by PLCs. Most of the devices are protected by non-trivial interlocks, which are implemented with ladder-logic software. Detailed information on interlock state and the individual interlock conditions are accessible for each device at the EPICS operator interface level. With the increasing number of ISAC devices, the interactive generation and maintenance of these displays with standard EPICS tools was too labor-intensive and error-prone. Software was developed, which uses a printout of the PLC program as well as reports from the ISAC device database to a) check the interlock implementation in the PLC against interlock specifications in natural language and b) generate device displays with a graphical representation of interlock state and details of interlock conditions.