Example of cascading MBP_MSTR in Concept IEC programming language.

Goals and Symptoms

Cascade MBP_MSTR

Causes and Fixes

Below is an example of how to cascade 3 MBP_MSTR's so that only 1 is active at a time. This concept can be expanded to any number of MSTR. Also a listing of the variable declarations is provided.

The first section is just a coil which signifies the first scan of the PLC. After that every 750ms the first MSTR will activate. The second MSTR will not activate until the first has completed or given an error. The final MSTR will activate based on the completion or error of the 2nd MSTR. Also all MSTR's are then reset based on the completion or error of the final MSTR. In the event of an error on an MSTR the error code is moved into a Register (MSTRx_Error_code) so that it can be seen even after the MSTR has been reset.