Centroid Community CNC Support Forum

While it was in velocity mode, did you measure voltage on the analog command wires?

Hi Marc, i have managed to measure across oak outputs 25 & 26 whilst trying to jog before i get the 411 fault. Results attached. No movement on the servo motor.I also found that if i try to gently turn the locked motor spindle by hand i also get a PID and voltage readout on pins 25 & 26 but interestingly if i let go of the motor spindle the PID value continues to rise until it faults out after a few seconds. Don't know if this is supposed to happen.
Photos attached.( The photo with the higher PID value was whilst trying to jog)
Many thanks
Chas

The issue is with the Mitsubishi drive configuration.

You have confirmed that the drive has line power, and is enabled.

You have confirmed that the drive is able to feed current to the motor, because you found that you could not turn the motor shaft when the drive is powered and enabled (meaning that the drive is applying current as needed to maintain its intended velocity, which is apparently zero).

You have confirmed that you are giving the drive a non-zero analog velocity command voltage. And yet the motor does not turn.

It seems that the drive is not using the analog voltage as its velocity reference source.

Apparently when you tried to configure the drives to run in pulse-train position mode, they did not move when given command pulses as well (though there are still several unknowns in that scenario).

I see in the Mitsubishi manual that it has limit switch inputs on CN1B pins 16 and 17. I did not connect these on the retrofit I did in 2016, because they had not been connected with the previous Anilam control. Presumably they can be (and were, in my case) defeated via parameter. That would be something to look into. If the drive thinks that a limit is tripped, it would probably refuse to move in that direction. If it thinks both limits are tripped, it would refuse to move in either direction.

In the Mitsubishi drive, try setting parameter 41 to 0110.

Thanks Marc, I’ll try that first thing.
Chas

Hi Marc, unfortunately changing parameter 41 didn't make any difference. i still get the 411 fault. I agree that it is looking like a drive issue and more than likely an incorrect parameter setting somewhere however i have been through the manual several times and can see nothing obvious that i have set incorrectly. I do have a spare drive of the same capacity so i'll swap them over and see if it makes any difference. It shouldn't as this drive and motor performed fine on the bench under the mitsubishi software. I'll also recheck the continuity on the oak to drive cable to be on the safe side but i think that's fine.

I hear Mitsubishi has decent support. You might give them a try.
Let them know you are trying to setup the drive in analog velocity mode and see if they can suggest parameter settings.
Its worth a try.
https://us.mitsubishielectric.com/fa/en ... s-melservo

Hi guys, i have movement. At the last test i had forgotten to change parameter 0 back to velocity mode after trying in position mode. Once i had corrected that and applied Marc's suggestion of changing parameter 41 the servos came to life. i can jog and input data from MDI at last. The servos turn relatively slowly at 100% feedrate but i'm guessing i need to get the manuals out to check where i need to make those adjustments. both X & Z pulleys move a full revolution correctly for the gearing for each axis so that's good. Wired up my handwheels to axis inputs 3 & 4 on oak as described in another post so that's the next job to figure out how to make them work.
I can't thank you enough for your patience in helping me through this. I'm not promising i won't be back for more help with the handwheels though.
Once the lathe is up and running i can turn back to project 2 which is a smallish CNC mill. (pics attached). built and machined from scratch including the enclosure. I made the patterns for the castings then had them cast at a little local casting company that specialises in castings for vintage and historic cars. Not cheap but really good quality castings. I had to get all the machining done before i retired so it was a bit of a rush near the end. I still have some mechanical stuff to do like the pneumatic BT30 tool release, X axis servo mounting and fitting the spindle motor but otherwise complete except the electrics. Hoping to run this one from Acorn but it'll be a while as i have some tidying up on the lathe once that is all functioning.
Many thanks
Chas

Good to hear of the break through progress.
Would be good if you can document all the parameters, connections, and a report for the next person that gives it a go with a similar configuration.

Marty

Hi Marty, good idea. Once I have got the servos to rotate at their rated speed I’ll get it all documented .
Chas