5i25/7i77 with Fanuc 3 axis servo drive Problems

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12 Oct 2016 17:01 #81581 by PotbellyMachine1
I have been attempting to bring to life a Saber 1000 milling machine.
The original control would no longer boot.
The machine has been made to move but I seem to have an issue with the encoders.
The fanuc 3 axis drive has reference voltage test pins for +- 15v and 0v.

As soon as I connect an encoder cable from the 7i77 to the drive the voltages skew..... (The -15 becomes approx -12.5 zero is 2.5 and the positive 15 reads 17.5)

This seems to cause the drive to creep, and also add false encoder readings. (Seems much worse on Y than X haven't moved Z yet)

The encoder cables from the drive only carry 6 wires.

It does not matter which encoder cable from the drives is connected to the 7i77. Any one or all cables connected produces the same result in drive voltage.

Thoughts?

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12 Oct 2016 17:22 #81582 by PCW
Sounds a bit like you are connecting 7I77 encoder 5V to FANUC GND

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12 Oct 2016 17:30 - 12 Oct 2016 18:13 #81583 by PotbellyMachine1
The drive is a A06B-6050-H402 3 axis unit.

Changed wording to be more clear.... Maybe...

The six wires in the cable are ABZ and /A /B /Z i verified pin out per the fanuc manual.

So it is not possible to connect the Mesa 5V to Fanuc ground to as it is not available in the cable. (The honda plug that goes into the drive has ground available on pins 1,2,3 but they are not connected to anything in the cable) The voltage on pins 1,2,3 skews with the 0V on the drive when A B and Z are connected.

I have not been using the 5v or GND connections on the 7i77 board as there are no outputs from servo drive to connect them with.
Last edit: 12 Oct 2016 18:13 by PotbellyMachine1. Reason: Added model of drive

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12 Oct 2016 18:18 - 12 Oct 2016 18:19 #81584 by PCW
Before you connect the 7I77 to the FANUC drives you should have a common ground between
The drive ground and the 7I77 ground or you may damage the 7I77, or the drives or both.

Are the FANUC voltage shifts relative to the FANUC gnd? That seems unlikely (that is I cannot see how connecting just encoder input signals would cause a shift in FANUC analog power supply voltages), but if the 7I77 GND is not common the the FANUC GND any measurements between the 2 systems are suspect
Last edit: 12 Oct 2016 18:19 by PCW.

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12 Oct 2016 18:27 #81585 by PotbellyMachine1
I am not using the encoders ground output on the 7i77. That said the 5v and 24v power supplies that feed the mesa's negative terminals are bonded to ground. The Fanuc drive is also bonded to ground. The voltage shifts on the Fanuc are measured using the test pins on the drive with the meters black wire connected to ground of the machine.

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12 Oct 2016 19:29 #81586 by PCW
Unless you measure the Drives analog power voltages relative to the drives analog ground
(which is likely isolated from frame ground), all bets are off

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25 Oct 2016 18:08 #82048 by PotbellyMachine1
Well finally had some free time to work on machine again.

I have X and Y moving OK now. (I had the A and B correct but index pins wrong oops.....)

Next problem.

Attempting to make the spindle move.

I used the pncconf to make my configuration.

I do not seem to get any output from port 5

I have looked at the sample mesa config files but they seem to only cover X, Y and Z

Don't know what to try next.

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25 Oct 2016 18:26 #82050 by PCW
I think there's a signal name error in some versions of PnCConf with regards to
the spindle speed command.

I would look at that section of the HAL file carefully

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25 Oct 2016 19:07 #82054 by PotbellyMachine1
I have attached the INI and HAL files I have been using.

I looked at the names as you suggested but nothing jumped out at me.

I have reviewed some of your posts regarding the matter and the names seem correct...

Maybe you could point me in the right direction.

Thanks,
Attachments:

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26 Oct 2016 16:09 #82090 by andypugh
Does the 7i77 have a spinena pin?
net spindle-enable => hm2_5i25.0.7i77.0.1.spinena

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