[ungie]

Hi Guys!

Today morning I have encountered the error described in the title. The machine Z axis was left nearly at the halfway of its travel length before powering down yesterday in the evening. I was able to get the machine boot up properly with the following trick:

1.: Power down the MC
2.: rotate the Z ballscrew in a few degrees by using a screwdriver at the coupling of the motor and the axis
3.: Power up the MC and We were ready to fly

The question is that what problem can cause the described symptoms and why does the above described method helps.
Please write down the exact description interpreted from the hex code to help me understand how to translate such coding in the future! (perhaps this is the most important for me now)
And in the end, I have encountered similar(not sure that the same) errors in the past, but only if the MC was turned off whit Z axis at the upper stroke limit.
That is because We have detached than the Z servo earlier and the PR ZERO OFFSET was not adjusted at all.


Thanks in advance!

[Algirdas]

Okuma absolute encoders are not endless. They are specified by length. 5m, 15m for instance. It's wise to set up axis work area somewhere in the middle of encoder length zone.
There could be a problem with some higher value bit and communication (the cable) also. And finally, could be some dirt or mechanical coupling trouble.

[ungie]

1.: I have no idea of where the effective zone was set up originally by Okuma tech (builders), but hopefully that is okay.(we can close this out as We already know that the error happened at near the centre of physical stroke of the axis.
2.: Cable fault is not likely, because during machining, this error never ever showed up, only at startup and only this time.
3.: There is no evidence of mechanical problems, as I check the rapid movement axis loads, and no unnatural noise at all.

So in the final I can only assume that there is some dirt on the glass plates, because the encoder was detached once in the past and even the tiniest dirt can produce strange symptoms on a precise unit like that.

Oh and Algridas!
Could You please tell me what did the hex code exactly told You!

Thanks in advance!

[Algirdas]

never seen glass or ceramics inside an Okuma encoder.
don't waste Your time learning what the hex or binary code is.
take away the encoder from the axis, move it (rotate about 20 times). (of course, control not powered)
make necessary parameter corrections. Launch the machine and note changes.
You will reduce one possibility of fault at least.

[underthetire]

Turn it more like 100+ turns. If your machine position shows something like 250 inches, turn it till you get 500 inches. Those encoders count from 1-999 inches. Not glass, most were a bunch of geared pots, similar to a household power meter.

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