Conveyor Zero Speed Switch

encoders connected to drive roller and take up roller. Counts from both can be used to sense those failures, also slippage under load for belt tensioning and belt over load.

In the PLC logic you could incorporate a timer that bypasses the ZSS, giving time for the conveyor to come up to speed (maybe 10 seconds or so).

Yep. Since the PLC is evaluating its logic at a much faster time rate than the starter can energize the motor and get its driven load up towards speed, a time delay in the program is the correct solution. Write it so the switch input is ignored for a brief time after the starter is energized. The suggested ten seconds is much longer than you need--try 2 or 3 seconds instead. Don't program it as a delay on response to a zero speed input. In other words, the input condition for the timer is the motor starter being energized, not the signal from the zero speed switch.

--JMM

Could you tell us more about the application?

minimum speed in rpm of the drive

a very basic & easy method is to install a tab or flag of metal on the driven shaft, use a proximity switch to send a signal to the plc

a couple of logic [software] timers

one to determine the shaft is above minimum speed

one to bypass for start up

I couldn't find any info on the relay you mentioned

I would guess it provides a simple output for either a moter starter or plc