Rockwell Automation 1902 Syncpro II - Manual (Page 25)

Rockwell Automation Publication 1902-IN001B-EN-E - April 2013 27
Installation Chapter 3
The ESR circuit ensures the motor is stopped for any fault condition occurring
either externally or when detected by the SyncPro II. Once the ESR has dropped
out (detected by the loss of I:2/7), the selector switch must be switched off and
on to initiate a start. This prevents a premature start if the fault condition is
cleared and the selector switch is still in the run position.
Figure 5 shows a typical three-wire control circuit. The STOP PB must be
maintained high in order to initiate a start and to run the system. The button also
ensures that the motor is stopped via the hardware circuit. The momentary
START PB is used to create a RUN (START) output signal of the same duration
as the input signal as long as there are no faults detected by the SyncPro II.
Figure 5 - Three-wire Control