Bench rig at school, TIA V18. CPU 1214FC DC/DC/DC and an ET 200SP with an F-DQ 4x24VDC/2A PM HF. I'm trying to switch a small 3RT2 contactor with a 24VDC coil off output 0 as a safety contactor exercise.
The moment the output goes TRUE the channel passivates. Buffer says "Read-back error" on channel 0 and the QBAD bit sets. The contactor clicks in for a fraction of a second and drops out again.
So I tried a second contactor out of the drawer, same thing, then output 1, same fault. A video said to put a diode across the coil, so I did that too and it made no difference.
Does the coil pull too much for the module? It's a 3RT2015, the coil is tiny. Or have I wired it wrong somehow, I've only got two wires so I'm not sure how. Could someone explain what the F-DQ is actually reading back while the output is on?
Part number of the module, the full 6ES7 one, and list me the wires: A1 to which terminal, A2 to which terminal. Exactly as they are, not as you meant them. And take the diode off until the manual says you want one, it isn't what's tripping this.
6ES7136-6DB00-0CA0. Wires: A1 to terminal 1 on the F-DQ, which the label says is DQ0 P. A2 to the 0V bus on the bench, the same bus the CPU and the 24VDC sensor supply sit on. The M terminals on the F-DQ I didn't use, I thought M is just 0V and the bench already has 0V so thats what I did. Diode's off now, same fault.