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strange Amp Fault on UMAC + Geo Macros
#1
Hi All

I am having a strange Amp Fault on my Hexapod system.

My current setup is:
- UMAC cpu w/ Macro accessory board over RJ45
- No. 3 Geo Macro (GMH152) that controls the six actuators of the hexapod

Sometimes, when I am in close loop, I get an Amplifier Fault on a motor channel (Amplifier Fault Error, bit 3 on Y:$C0) without any other error on the Geo Macro (the LED on the GeoMacro is fix to 0 and the control word MI4 does not report error) or Macro Ring (no faults on the ring).

This error triggers appears almost randomly when I am in close loop: it can trigger both when I am moving at high speed, slow speed or even stilling a position (with very small currents flowing into the motor).

Do you have any idea on where I can read what triggered the Amp fault?

thanks
gigi
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#2
Check that you are not writing to the MARO Flag Register (X/Y$3440) as pointed to by I125 for motor 1. This location is where MACRO places the actual hardware flag information.

Does this happen for any other motors?
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#3
Hi Steve

(05-29-2013, 04:03 PM)steve.milici Wrote: Check that you are not writing to the MARO Flag Register (X/Y$3440) as pointed to by I125 for motor 1. This location is where MACRO places the actual hardware flag information.


I don't write in $3440 registers; does an eventual write there cancel the status of the LED in front of the GeoMacro?


(05-29-2013, 04:03 PM)steve.milici Wrote: Does this happen for any other motors?

Actually, in about 10 hours of work, I had the problem only on that channel/motor. The customer says that sometime it happens on other motor, but I'm not sure they are looking at the same problem I am investigating.

thanks!
gigi
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#4
Check to see if bit #15 of X$344n is getting set - this is the Amplifier fault bit. If the actual amplifier is not showing a fault something is writing to this bit.
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#5
(05-31-2013, 09:48 AM)steve.milici Wrote: Check to see if bit #15 of X$344n is getting set - this is the Amplifier fault bit. If the actual amplifier is not showing a fault something is writing to this bit.

As an aside we have a couple of geoMacro drives here which don't report 'fault conditions' on the front panel led which is confusing. As yet these drives don't generate random amp faults.
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#6
If there is no fault at the drive and you are certain no code on the PMAC side is writing to the fault bits this could be a result of noise over the RJ45. Are you using individually shielded twisted pair cable? Also check the wiring for loose/intermittent connections.
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#7
(07-11-2013, 02:27 PM)steve.milici Wrote: If there is no fault at the drive and you are certain no code on the PMAC side is writing to the fault bits this could be a result of noise over the RJ45. Are you using individually shielded twisted pair cable? Also check the wiring for loose/intermittent connections.

I have news on this topic: with the help with the guys on DeltaTau Switzerland, we discovered that we had some problems deep on the Macro. The GeoMacro did not report anything, the front led was 0, the mi5 (macro counter) was 0, but the i6840 was set to $4077 instead of $4070.

We then decided to replace the macro board (I had one here, that was supposed to be the spare for that machine) and it seems we fixed the problem: i6840 is now set properly to $4070 and we did not get any of this amp fault anymore (since last Monday).

Now, I have here in my office the "bad" Acc 5E; I installed it in my system (UMAC + 1 GeoMacro) and i6840 magically changed to $4077 from $4070.

Can we say now that this is a board issue?
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