Centroid Community CNC Support Forum

Scott,

You are AWSOME!!!! You fixed the problem. Not a bad relay, just my lack of PLC programming skills on my part. The PLC programming manual looks like it will be a big help, thanks for making it available. Now I just need to come up to speed.

Thanks for the parameter 178 inversion tip, had to do that.

Should I be thinking about a clamp_ack association with the controls so a rotation move can't be done/attempted if the axis is clamped or is this already taken care of? I'm thinking of associating clamp_ack to Aux4 LED so I will know if it is activated and Aux4 button to turn the clamp on or off manually if needed.

I did notice that the clamp_ack has AC on it of about 6-7 Vac @ 1uA when the line is not pulled low, and about 12vdc instead of +5vdc. This happens when the solenoid is activated. I disconnected the cable that goes to the 4th axis and the problem goes away so I'm thinking the noise in the long cable that goes to the 4th axis. I suspect that because the wires for the "Home" signal and the "clamp_ack" as well as the solenoid power go through a single wire bundle that noise is being picked up. They may not be twisted pair (needed for common mode rejection of noise). Think I will run a separate shielded twisted pair wire just for the air solenoid, this should solve the problem. I write this in case other encounter the problem.

Thanks again!!!

Hello,

The idea of a clamp_ack is a good one and mapping it to an LED would provide an indicator to alert the operator that the axis shouldn't be jogged or commanded while clamped. -though you could just as easily just watch the clamp output itself (and assume that if the output is on, it's actually clamped) Unfortunately, the PLC has no idea whether motion is being commanded in CPU10 systems so there is nothing it can do to prevent it. You could add some macros and wrap them around all your rotary moves but it still comes down to explicitly adding commands or requiring that the operator unclamp the axis before moving.

In newer CNC11 systems, the PLC can prevent jogging and also can monitor the encoder input to determine if motion is trying to be commanded on a clamped axis and issue a fault or warning.

wtecksolutions wrote:
I did notice that the clamp_ack has AC on it of about 6-7 Vac @ 1uA when the line is not pulled low, and about 12vdc instead of +5vdc. This happens when the solenoid is activated. I disconnected the cable that goes to the 4th axis and the problem goes away so I'm thinking the noise in the long cable that goes to the 4th axis. I suspect that because the wires for the "Home" signal and the "clamp_ack" as well as the solenoid power go through a single wire bundle that noise is being picked up. They may not be twisted pair (needed for common mode rejection of noise). Think I will run a separate shielded twisted pair wire just for the air solenoid, this should solve the problem. I write this in case other encounter the problem.

Update on clamp_ack AC noise. (Solved)

I added another wire to the 4th axis cable snake, it was twisted pair and shielded. I ran the clamp solenoid AC through this new wire and the shield to common on DC3IO (this is where the other signals reference ground). This solved the problem, no more AC on clamp_ack and DC on clamp_ack is now at proper voltage when the signal is in a high (logic 1 or +5vdc, floating) condition.

The problem was caused by the "Home", "clamp_ack" signals as well as 120VAC for clamp solenoid being run through a 4 wire bundle as well as not being shielded. Running signal wires in parallel with AC for long distances (20ft.) will induce AC into the signal wires much like a transformer.