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Post by paulg100 on Apr 11, 2016 10:09:59 GMT
OK FINALLY finished the re-wire and motors are running again. Motors are silent at home so EMI problems finally seem to be tamed.
Replaced both UDN2981 chips to be sure there are no more issues there.
Now a have a new issue which I didn't have when sim was running before re-wire.
motors 1,2 and 6 are running normally
But motors 3,4,5 will only return home from one direction (left).
If I move the motors right they do not return home after release button and rotate 360 until they reach home again.
I can manually get them home after moving right by pressing left button until they pass home position but they do not re-enter after moving right on their own.
So 3 motors are only re-centering from 1 direction.
Ive tried swapping a pot from a known good motor but didn't make any difference. EDIT: Also tried different pot cable to AMC, didn't make any difference.
Has anyone come across this behavior before?
Maybe its possible one of the other chips on 6dof board is faulty now?
thanks.
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Post by tronicgr on Apr 11, 2016 11:41:04 GMT
Hi,
Can you test the amc1280usb and the 6dof on the bench for the following?
Do not connect the 24v.
Connect 1 pot as centered is possible.
Measure the voltage in the pins between the 595 chips and the 2981.
Do they transit from 0-5v or 5-0v while pressing manually left and right buttons?
The test above is to verify that the logic chips for the direction didn't get also burned along the power chips, I seen one 595 chip bad just last night...
Thanks
Thanos
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Post by paulg100 on Apr 14, 2016 19:51:57 GMT
OK thanks for the advice thanos,
because of mounting the amc in the emi box it is a bit of a pain to connect all the wires now so before discconecting again to bench test
i thought id order some spare 595 chips anyway.
so i put 2 new 595 chips in today, the problem still persists. 3 motors only return home from 1 direction the other 3 are working normally.
now that 2 new 595's are in, is this likely to indicate another cause? or maybe ill still pull the amc out at the weekend and bench test as above anyway.
thanks.
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Post by paulg100 on Apr 17, 2016 15:51:31 GMT
OK amc out for bench testing and checked voltage on pins between 595's and 2981's.  Results: 595 Chip 1 - reading 0-6.9v or 6.9-0v across pins 1-4 and 6-8. Pins 5&6 read 0.6-6.97v (dont zero) 595 chip 2 - reading 0-6.9v or 6.9-0v across pins 1-4 , ZERO across pin 5-8 EDIT: im guessing the last 4 channels are unused and two channels (pins 5-6) that dont register 0 may be the ones with the pot on which is not dead center. tronicgr Is this correct Thanos? These readings were taken with new 595 chips inserted. Thanks, EDIT: OK ive tested motors 3,4,5, with the amc "on the bench" and am glad to say they all seem to work correctly here. SO there is obviously something up with the wiring in the EMI box or possible brakes in the pot cables. The hunt continues but at least i know the amc and 6dof board are all working correctly. |
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Post by tronicgr on Apr 17, 2016 22:18:21 GMT
You said you are measured 6.9v on the outputs of the 595 chips? That should be 5v max... Is that measured while you had the 24v connected in the 6dof ext board?
I'll have to verify this with my setup... Hmm never noticed these values before. Must be a leak or something. I have an unpopulated reverse diode there for such leaks but didn't need it so far. Let me check that.
Thanks
Thanos
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Post by paulg100 on Apr 18, 2016 8:03:40 GMT
OK thanks thanos,
Yep its 6.9v.
That is without 24v power.
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Post by tronicgr on Apr 18, 2016 23:58:09 GMT
Ok, how much is the voltage on the +5v headers, on the 6DOF and the AMC1280USB boards? That doesn't sound good! Perhaps the regulator failed!
Thanks
Thanos
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Post by paulg100 on Apr 19, 2016 19:36:14 GMT
OK tested +5v headers on AMC, on 6DOF and retested pins between 595's and 2981's with oscope. All without 24v power. First +5v headers on AMC.  Then +5v on 6dof  |
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Post by paulg100 on Apr 19, 2016 19:38:30 GMT
Then pin between 595 and 2981 no direction  then pin between 595 and 2981 with direction.  Interestingly if I test with a multimeter it still reads 6.6+ instead of 5.6v as above, don't know why the difference. Probes on oscope are calibrated. |
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Post by paulg100 on Apr 19, 2016 19:45:50 GMT
Hopefully the above looks OK or is there anything I need to worry about there?
Also some good news, All motors are finally working correctly again.
The jitter noise is back with vengeance on motors 1-4 though. On motors 5&6 I changed the pot cable out for USB cable and they seem much quitter.
motors 1-4 are still using my original pot cable which is 2 core shielded speaker cable where shield is used as ground as was recommended in another thread.
After reading about EMI using the shield as ground seems to go against the grain as the shield should only be terminated at one end.
The shield on pots is also stripped and grounded to the EMC glands into the EMI box so maybe this is making things worse there.
Ill change the other 4 pots to usb cable and see if it helps before diving into more testing with oscope.
But at least things are moving correctly again at last!!!!
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Post by GA-Dawg on Apr 21, 2016 16:36:49 GMT
Hi Paul,
Well I finally got my rig up and run and I had a gitter problem as well. In my case it was because the pot signal/24v feed was reversed so the AMC was send the up signal when it should of been sending down. This is how I tested/corrected it. On the AMC I have the sensor direction all set to pos (Pos 1-2-3-4-5-6). Remove the pot from one of the motors. With the shaft facing toward you turn it right. The lever on the motor should go in the opposite direction. If it does not swap wire 1 and 2 around on the Hitachi.
Hope that helps
Brian
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Post by paulg100 on Apr 21, 2016 18:56:31 GMT
Thanks for the tip GA ill take a look at that over the weekend.
All my arms run correctly but when the arms return to home there is electrical jitter where the pots wont settle at complete 50%, is this the same issue you had? or were you getting oscillation in the arms?
Hopefully some more USB cables will arrive tomorrow so I can wire the other pots, was never happy with using the shield of the previous wire as ground so it will be a worth while exercise
I think.
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Post by GA-Dawg on Apr 21, 2016 21:50:34 GMT
Hi Paul, I was getting oscillation on the arms. Everything is good now just need to start tuning. Doesn't sound like the same problem but though I would share. Couple of images. AMC Screen Pos 1-2-3-4-5-6  Edit....After I actually start tuning I realized I was wrong. Had to make the AMC 135 Neg and 246 pos. Also had to move the wires around. |
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Post by paulg100 on Apr 22, 2016 5:41:42 GMT
HI GA, OK thanks
Yes its a different issue my arms are stable and working normally I just have this pot/VFD jitter where I cant get the pot to settle at 50% without feedback.
Out of interest what type of signal cable did you end up using?
thanks
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Post by GA-Dawg on Apr 22, 2016 13:53:28 GMT
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