awb (Customer) asked a question.
Click PLC SC1 bit cycling on and off
I was troubleshooting a machine with a Click PLC. I had an internal output bit (non-latching and nowhere else in the program) that was dropping out and causing the ma chine to stop. There was one open contact on the same rung which was tied to a physical input on the PLC. The input comes on and the internal bit comes on...the.input goes off and the internal bit goes off. I removed the input bit and added an SC1 (always on) bit in its place and ran the machine. The machine stopped again. I then branched out from inbetween the SC1 bit and the internal ouput bit and added a counter. Each time the machine stopped, the counter would increment by 1. Has anyone seen this behavior before?
Hi @awb (Customer)
Can you attach the program and tell us what rung to look at? Perhaps this is used as a word, and the bits are then split up.
Is the PLC always in run mode? Maybe the supply is low enough, and the PLC itself is turning off.
Just a couple of thoughts.
Regards,
Garry
https://accautomation.ca/series/click-plc/
When the 'machine stops' do you have to place the CPU back into RUN mode?
Are any of the bits between SC19 and SC46 on when the 'machine stops?'
Welcome to, "The SC1 bit does not have the same behavior" as the same bit in other controllers.
Sounds like you're losing power to the Click. Are you using the same power supply for your I/O as the one powering the Click's CPU? If so, the Click's CPU needs to be on its own power supply. Next, check for voltage drop to your I/O.