Master Control Reset Instuction for Allen-Bradley SLC 500 ...
The Master Control Reset (MCR) instruction is used in pairs to create zones that clear all set outputs within that zone; i.e., it turns off all the non-retentive outputs in the zone.Non-Retentive outputs do not retain their memory when de-energized and are reset. The rungs contained within the two MCR commands called a zone are still scanned, but the scan time is reduced due to …