RE: Ini file

[Mike Warehime <m.warehime-at-comcast.net>]

So I have a question for those on the group..

I am working for a company that has a lot of gooood iron..  Some old
equipment but very very good machinery.  One that peaks my curiosity is a
Moore Jig borer that is unlike others that I have seen.  It had a servo or
stepper drive type of system on it.  Very old.  The machine as I have been
told is the most accurate piece in the precision room cause it hasn't been
worn out.  I am not sure how old the drive system is.  My guess is late
60's.  Do you think it would be possible to scab into the drive and run the
motors with EMC.  I am pretty sure it has encoder feedback and am very
curious.  The console on this bugger has round punch keys reminiscent of a
1955 typewriter with what looks like record and store type of
programmabilty.  Any guess what I would need to check into to see if I could
run the motors????  The machine has been in a controlled jig bore room for
years.  Perfect temp and humidity.  It has me warm and fuzzy...

Mike Warehime

-----Original Message-----
From: emc-at-nist.gov [emc-at-nist.gov]On Behalf Of Dean L. Hedin
Sent: Tuesday, April 02, 2002 9:48 PM
To: Multiple recipients of list
Subject: Re: Ini file



> and restricting z axis acceleration orspeed does not help?

The only problem with that is sometimes I would like the Z to move
quickly!

The problem only seems to occur when I am moving at the fastest feedrate
(F7.0 units inchs) and more than one axis is involved.

Also keep in mind that this is in gcode produced by my emcprobe program
and consist only of a series G01 X Y Z movements.  on a 1/20in.  XY grid.
As it is moving along it suddenly hits a point where the Z drops quickly.
and this is the time that I loose Z steps.

So what I've done in the filter program is to watch the delta z between two
succesive points and insert a feedrate command to slow it down.  I've set
it up to apply a different feedrate for various ranges in delta Z so that
I don't end up jumping drastically from one feedrate to another.  For the
time
being this has resolved the issue at hand.

I should also mention that I am running NEMA34 motors 1.4 AMP 5V rated
and I am not running them above rated voltage.  I have'nt improved my driver
board yet!  I don't think this is an issue because the problem occurs even
on
dry runs with no workpiece in place.  As configured the motors have
sufficient speed and torque for the task at hand.

I will fiddle with acceleration values to see if that helps.

> > perhaps if you have a shared power supply, it has insufficient reserve
> > power to move all the axis at once ? You could use more/bigger supply
> > capacitors or
>
> unlikely with stepper motors.  the current they draw goes down a touch
> when they are moving.
> john

Concur,  When I initially encountered this I added a large electrolytic to
the
motor supply.  Did'nt help.   Supply looks good on the scope.