partner 1 servo encoder issue

[fcycles]

I have a partner 1 with centurion 5
I have always had issues with the x axis.
Usually i just clean out the tach brushes and armature and it's good to go again. Recently it just went off out of nowhere and butchered my part and bit. Thinking it was the same issue i pulled it apart and cleaned the tach, It worked for about a month just fine but i had finish issues when x and y were both moving, it left a chattered finish. x only nice finish, y only nice finish x and y on an angle and it looks chattered.

Well it started to rapid left and right right out of e-stop and would throw itself back in to e-stop from "x axis excess error" . Pulled it apart again couldn't see any issues and test ran it. Same thing. moved the wiring around and tried again. Same thing. Thought what the hell and moved it around again and ran it but this time it worked for a minute then back to the problem again. I ended up finding the servo + wire with a small area exposed and figured it was grounding causing the problem, so i issolated it and tried again.
Same thing, left and right until it e-stopped from excess error but this time the motor just sat there and spun slowly with no movement recorded on the screen. I ordered an encoder thinking that was the issue.

Just put it in and same thing it just spins slowly but no eradtic left and right like before. I swapped glentek cards from x to y and still the same problem. I've tried changing + and - on several wires thinking maybe something was out of phase with no results. It just acts like there's no encoder, i have 5.05 volts coming in and i can see a signal coming out on A and A_ line from the encoder.

I suspect the + servo armature wire grounded and may have caused a problem but don't know where it might be at this point. Anyone have any ideas?

[ZZZZ]

When the machine is in E-Stop condition, the encoder feed-back should still display on the screen. Check the connections between the encoder and the X Axis connector. When everything is good, you should be able to spin the motor (encoder) and see the DRO value change.

I've replaced the X axis cables many times, especially on machines with seal-tite. The X cables are the only ones that move and flex. Over time, coolant can harden the insulation, the seal-tite will crack, and coolant and chips will get inside. The chips can cut through the insulation and cause short circuits. Milltronics has also used a 'composite cable' here. These get hard and stiff and can have broken conductors inside.

Sometimes, you need to replace the seal-tite and/or the cables.


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[fcycles]

Thanks for the tip zzzz, I checked the wiring it was o.k. , No dro readout still. I have been getting coolant contamination in the x servo which has been messing with the tach but usually when it happens i just clean the tach and away we go again. I finally got it all sealed with no sign of leaking into the servo when this happened.

I think i narrowed it down to the acroloop card in the cage. I swapped the x and y motion cards (i think they're called) and nothing changed but today i swapped the axis plugs from x and y on the card cage itself and x worked fine but y started drifting so i think i need a new acroloop card for the x axis which i can't locate so far.... I don't suppose you would know where to locate one?

[ZZZZ]

You want to check that the MISC parameter Digital Read Out in E-Stop is set to a YES.

Finding a replacement card might be difficult, I got the last new or used one Milltronics had. I think you can still get the Y, Z, A axis acroloop cards from them. Milltronics can upgrade your card cage to the Cent6 motion control thereby eliminating the acroloops and replacing them with a NCBlaster card.

To find an acroloop controller card, watch E-Bay. I have seen whole card cages sell there.

[Al_The_Man]

What model card is it, 8000 or 2000?
A common problem on the 8000 is the encoder input IC, I have changed these on occasion, I would have to look it up as to the IC # as it has been a while.
I have 2000 cards by the way, they actually will replace the 8000 but the pinouts are different.
Al.

[fcycles]

Thanks Al,

I'm not sure what series it is, i can't find a 2000 or 8000 on the card anywhere.
That would make sense that the encoder input IC went out because it acts like there's no encoder at all, the servo just slowly drifts. I attached a few pictures of the card maybe you can tell by the pics?

Thanks!!

[Al_The_Man]

That's a new one on me, I used to be a Acroloop integrator and I still have all the old catalogues and I don't see one with a ribbon cable connector on the end?
I have details on the ISA 8000,6000,2000,1000.
Unless it was a special for that machine.
In any case it may use the same IC's, they would be the socketed IC's below P3 P4.
The 8000 used 26LS32 's.
Check the number in if they are the same or differential recievers, then a couple of $$ may cure the problem.
Make sure there is no shorts on the wiring.
Al.

[fcycles]

the other 2 axis cards don't have that plug, the x for some reason also controls the keyboard. At least when i left that plug unplugged it threw an error saying no keyboard. So it must at least be supplying power to it.

I do see the the 2 IC's below p3 and p4, they're MC1412P or ULN2002A.
I did find a spec sheet online for them and found them for sale online for about $.67 each. It says they are high voltage,high current darlington transistor arrays. Does that seem like what we're looking for? That sure would be nice if that would fix it. I don't know much about testing them but using the pin connection and flow diagram i found can i just test it with my fluke meter like a diode and if it flows 2 directions it's bad? That might be a dumb question but thought i'd ask.

Thanks for your help!

[Al_The_Man]

Those IC's are not usually used for differential drivers, they are more like PLC output functions, But by using a ohmeter you could trace the pins from where the encoder plugs in to the an IC that shows continuity from the IC to the ribbon socket to identify the IC for sure.
Al.

[fcycles]

I found the first chip it goes to is this one, Does this look like the right one?
Thanks a ton for your time and help!

[Al_The_Man]

That is a RS422 receiver so that should be the one.!
Is it socketed or soldered?
Al.

[fcycles]

Awesome! It's soldered unforunately, as long i take my time i should be able to replace it, it's worth a shot anyway.
I doubt there's any way to test it without removing it first?
I found some on ebay but most are texas instruments not motorolla.
They should be the same anyway?? Same part#...