On Sat, 10 Jul 2010 10:50:15 -0500, "Pete C."
wrote:


Gunner Asch wrote:

On Sat, 10 Jul 2010 09:44:21 -0500, Ignoramus30064
wrote:

On 2010-07-10, Gunner Asch wrote:
On Sat, 10 Jul 2010 01:45:39 -0500, Ignoramus30064
wrote:

... Because it "creeps".

I have only one axis (x) wired right now. When the drive is powered on,
but with no input signal, the table imperceptibly slowly creeps. I
only noticed it because some tools fell off the table as it moved by
perhaps 8 inches in an hour.

There is a "test/offset" pot on the board that, if turned properly,
shifts input signal and makes the table move. I could easily set it so
that the mill does not _visibly_ move. I have not, however, been able
to get rid of the slow creep.

I may call AMC on Monday to find out.

i

Either you have voltage on the input (1-10vt) or you have rate
gain/test offset set too high. Test your input on a millivolt scale and
see if there is a trickle of power getting to the servo. Sounds like
there is. Might want to put in a 100 ohm resistor or something to get it
down to nada. If you have a scope..check it for trace AC as well. it
should be clean DC coming in...or nothing at all. If you have a leaky
diode..you might be getting a trace of AC or flutters.

I use a lot of AMCs on OmniTurn cnc lathes..but dont want to compare
them with mill uses.

Maybe it is a gain issue.

There really is no input: I use a reversing Lego switch to send signal
to from a little power supply to the amplifier, and the switch was off

i

The quick and dirty adjustment for Omniturns that use the AMC amp..is to
turn the loop gain up until the servo starts to whine and then back it
off 2 turns

http://omniturnfactorydirect.com/Omn..._G3_100128.pdf
page 172 for the newer Glentek amps.

Ill have to hunt around a bit for docs on the old AMC amps. Its in my
books..but...

http://omniturnfactorydirect.com/Omn..._G4_100611.pdf
Check page 176....its close.

Looks like they have upgraded the control once again..havent seen this
one yet in the field.

The software built into the main program has internal assists..so this
may not be of much help to you.

http://www.omni-turn.com/Pages/Techn...djustment.html

Btw...when the servo moves without input from softward or operator..its
called a "runaway" in the biz.

Might help when doing google search

Iggy does not yet have a servo loop operating, therefore he can not tune
the loop or the drive at this time.

True indeed. I wasnt aware he was not "there" yet.

Gunner

One could not be a successful Leftwinger without realizing that,
in contrast to the popular conception supported by newspapers
and mothers of Leftwingers, a goodly number of Leftwingers are
not only narrow-minded and dull, but also just stupid.
Gunner Asch