opaji
Member
Hi, this is a problem that has been dogging me for months and I thought I'd ask here.
I have a Direct Logic 05 PLC that I am using to interface a high-speed spindle with a Haas CNC machine. The CNC machine has a relay output that it uses to call peripheral devices, and it watches for a feedback signal on another pin. The PLC watches the spindle motor drive for errors and sends the feedback signal if there are none. If there is an error, the PLC opens a NC relay which is wired into the CNC's E-stop circuit.
We had been having weird errors where the CNC would stop running in the middle of a job without going into E-stop, so we removed the NC relay and replaced it with a jumper. So far the mystery error has not come back (one month).
Do I need some kind of transient protection on the NC relay output? I am fairly certain that the PLC was not sending the E-stop command because when I force an error on the drive the CNC machine goes into E-stop, not the mystery state.
I have a Direct Logic 05 PLC that I am using to interface a high-speed spindle with a Haas CNC machine. The CNC machine has a relay output that it uses to call peripheral devices, and it watches for a feedback signal on another pin. The PLC watches the spindle motor drive for errors and sends the feedback signal if there are none. If there is an error, the PLC opens a NC relay which is wired into the CNC's E-stop circuit.
We had been having weird errors where the CNC would stop running in the middle of a job without going into E-stop, so we removed the NC relay and replaced it with a jumper. So far the mystery error has not come back (one month).
Do I need some kind of transient protection on the NC relay output? I am fairly certain that the PLC was not sending the E-stop command because when I force an error on the drive the CNC machine goes into E-stop, not the mystery state.