wilkerson29847
Member
Good morning all.
I looked through previous posts and didn't find any help on my exact problem. I have a 1769-L33ER PLC running a water jet cutting robot cell that interfaces the operator controls with the robot controls. Last night they had problems with the cell not responding and investigated it for quite a while. I finally got called in at around 3:30 am. The PLC was set to "remote" on the switch on the front of the PLC. When I went online I found the PLC had switched to remote program mode. Since there is no one else with PLC access in the facility, I know that no one went online and switched it from remote run to remote program. The box is not checked on any of the ethernet modules to cause a major fault on the PLC if communication is lost in run mode and there is no fault routine in the PLC that would cause this. Does anyone know what would cause this? Has anyone ever seen this before? Would someone accidentally causing a short on the 24 VDC power during their troubleshooting efforts cause the PLC to switch to remote program to "self protect" the outputs if that happened?
Note: I have experienced this with other AB PLCs and never found out why it happened but I always had a suspicion it was something to due with a short on the 24 VDC circuit.
I looked through previous posts and didn't find any help on my exact problem. I have a 1769-L33ER PLC running a water jet cutting robot cell that interfaces the operator controls with the robot controls. Last night they had problems with the cell not responding and investigated it for quite a while. I finally got called in at around 3:30 am. The PLC was set to "remote" on the switch on the front of the PLC. When I went online I found the PLC had switched to remote program mode. Since there is no one else with PLC access in the facility, I know that no one went online and switched it from remote run to remote program. The box is not checked on any of the ethernet modules to cause a major fault on the PLC if communication is lost in run mode and there is no fault routine in the PLC that would cause this. Does anyone know what would cause this? Has anyone ever seen this before? Would someone accidentally causing a short on the 24 VDC power during their troubleshooting efforts cause the PLC to switch to remote program to "self protect" the outputs if that happened?
Note: I have experienced this with other AB PLCs and never found out why it happened but I always had a suspicion it was something to due with a short on the 24 VDC circuit.