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Bridgeport Mill Fault Codes <resolved, loose estop wire>

Posted: Tue Oct 12, 2021 10:49 am
by compfast
I upgraded my Bridgeport Interact Mill a few years ago with Centroid Allin1DC and have been really pleased with the result. However, powered up the machine a few days ago after not using it for a few weeks and started to get faults:-
410 “Z axis position error” also 411 “Axis full power without motion” (Nothing fouling and well away from any travel limits) I powered down and powered up several times. Sometimes it ‘homes’ OK, sometimes not ?? Also had a 907 “fault Y axis travel exceeded”
Checked the servo motor earth wires. Also removed and stripped the Z axis servo and checked the encoder mounting still secure. The machine ball screws have no backlash.
The servo motor cables to the Allin1DC are not screened ??
Any suggestions gratefully received.
Report File attached
Phil

Re: Bridgeport Mill Fault Codes

Posted: Tue Oct 12, 2021 2:55 pm
by cncsnw
"410 _ axis position error" and "411 _ axis full power without motion" stall messages can be caused by a lot of different things.

If, when they occur, the axis is rapidly running away, then "410 ... position error" is usually either a wiring polarity error (not something that develops spontaneously) or a drive transistor failure; and "411 ... full power without motion" is usually and encoder failure.

If, when they occur, the axis is not moving (or is ceasing to move when it should have continued) then either error is usually a failure to get power to the motor, or to convert that power to torque.

In those cases, the next question is whether it affects all axes at different times, or whether it only appears on one axis. To test this, you can use the jog buttons to try jogging each axis, without necessarily homing the machine. Since the home cycle always moves Z first, if the first and only thing you do is try to home, you will always get stall messages on the Z axis, even if the problem affects all axes equally.

If the problem only affects one axis, it could be a faulty motor; faulty motor cable; or damaged servo drive output.

If the problem affects all axes, then it probably relates to the DC motor supply going into the drive (VM+ and VM-): perhaps due to a faulty emergency stop contactor, or to a bad connection somewhere.

Re: Bridgeport Mill Fault Codes

Posted: Tue Oct 12, 2021 2:58 pm
by cncsnw
"907 _ axis travel exceeded" is neither a fault nor a stall, and would be entirely unrelated to any 410 and 411 stalls.

"907 _ axis travel exceeded" means you asked the control to move that axis outside the boundaries of your software travel limits. For example, immediately after homing, if you press the Y+ jog button, you will get "907 Y axis travel exceeded" because you are already sitting at the Y+ limit of travel.

Re: Bridgeport Mill Fault Codes

Posted: Wed Oct 13, 2021 4:25 am
by compfast
Thanks for this. Will do some more checks Phil

Re: Bridgeport Mill Fault Codes

Posted: Wed Oct 13, 2021 3:35 pm
by compfast
Just done a few checks. Selected MDI. The machine jogged fine on all three axis at low feed rate 10%. Increased to 50% also fine. On 100% the Y axis tripped with 411 fault. Shutdown the machine and powered up again an hour later. I then jogged ok on all axis. I then homed the machine and ran a program at 100% feed rate with no issues ??? There is a fault somewhere which is not specific to any axis ??? Any suggestion on what to try next ?? Thanks in advance Phil

Re: Bridgeport Mill Fault Codes

Posted: Wed Oct 13, 2021 4:39 pm
by cncsnw
If you have the tools (e.g. a digital storage oscilloscope that can monitor 160VDC) and the ability to set them up safely, you could monitor the voltage at the VM+ and VM- terminals going into the Allin1DC unit, and see what happens at the moment an axis stalls.

If your emergency stop contactor uses a DC coil, then you could use a falling edge of the voltage on OUT1 as your scope trigger (detecting when the PLC program has opened the emergency stop output in response to the stall condition).

If your contactor has an AC coil, that won't work, but you could wire a DC circuit through OUT9 (the Z brake release output, which you probably are not using) and trigger on that, since OUT9 will turn on when the Z axis is enabled (e.g. when you jog it, or home the machine, or start a program cycle, or open MDI), and OUT9 will turn off in response to the stall condition.

If you do not have the ability to monitor VM with a scope, then you can only hope that the condition persists long enough for you to usefully measure the voltage there with a volt meter.

Re: Bridgeport Mill Fault Codes

Posted: Thu Oct 14, 2021 5:32 am
by compfast
I dont have an oscilloscope. The Estop contactor coil is fed from the original Bridgeport transformer which is 24v AC. I noticed contactor does not have a snubber fitted. The other contactors have them but I must have missed this one. Also the Out9 I am using for the spindle brake. I will try and monitor the VM+ and VM- voltage and see what I can get Phil

Re: Bridgeport Mill Fault Codes

Posted: Thu Oct 14, 2021 6:51 am
by polaraligned
When the Estop contactor is closed and motors drawing current idling, measure the voltage from one side to the other, across each closed contact. If the contacts are failing you will see a voltage drop across them as they develop a high resistance. I doubt the snubber is an issue as the machine has been running for several years already.

Re: Bridgeport Mill Fault Codes

Posted: Thu Oct 14, 2021 11:59 am
by cncsnw
Also the Out9 I am using for the spindle brake
That is odd. The PLC program in the report you posted has no spindle brake logic. It uses OUT9 for a Z servo brake release.

Re: Bridgeport Mill Fault Codes

Posted: Fri Oct 15, 2021 9:28 am
by compfast
Have currently wired in a voltmeter. Of course when you are waiting for a trip to happen, it wont happen. Vm voltage is 156v dropping to 150 when moving. Will continue
The machine is wired generally as Drg S/14760. This drg refers to using H6/OUT9 for the spindle brake although on parts of the drawing it refers to Z axis brake which I assumed was an error. What is a Z servo brake ? Phil