First time with QS PLC, Starts up in stop

[WattUp 34]

We have a brand new system that is using a QS PLC for the safety controls. This is new for us as we mostly use programmable safety controls or relays. 

 

Well Our integrator left yesterday (without showing me the final process, long drama filled BS)  so today I begin testing the system and the first thing i noticed is that from power-up, this safety PLC is coming on in STOP mode.  The only way to recover is to open the live cabinet, and manually switch the sCPU to stop/reset.

 

This seems like a pretty dumb oversight that I am hoping can be corrected easily. 

[dunc 8]

we had a similar issue with an omron safety plc. when installed they had an issue with a safety input so it would always power up with a fault and not allow the outputs to run the system until reset..

once the safety fault was corrected, it was ok. it could be that something is starting up in a fault condition when you put the power on which is putting the safety plc into stop? 

it is hard to suggest a suitable way around this without knowing a bit more about the system. unfortunately, i havnt done much with safety PLCs myself either.

[Crossbow 295]

Are you certain it has a valid program in it?  It works fine after you cycle the switch?

Most PLCs do have an option setting to power up in program or run modes.  Can't say where to look it's been almost 6 years since I've had to look at QS.

[WattUp 34]

Solved.. 

 

Discovered the issue only happened when using a Control Power Keyswitch and not the full panel disconnect. This made me look into the key switch circuit, and I found that the QS PLC had power maintained, however the safety I/O module did not, hence the stop condition because communication was lost to the I/O