Hi Don, Nasir,
Good to hear from you Don. My X and Y encoders are the same ---
automation direct Koyo: TRD-S2500-VD.
Not the fanciest on the block but certainly usable. IIRC my X gave
offset problems but the Y did not.
Don, I wish I did remember because it might help my cause also. On my
X axis I actually went back and spliced the original encoder cable
back into the stream complete with the star grounding... to no avail.
I just looked up the PID values for the Mazak at Cardinal
Engineering..... this is for torque mode so certainly will not
translate directly to another machine whether running torque or
velocity mode. PID was 4000, 6400, 15. By my way of thinking
pretty drastic. But then that is emc2 not emc1 where I had my
experience.
If anyone has flashes of recall it might help both of us.
Ray did make some comments about difficulty getting the grounding
configured as a star with the vital breakout board. John K may have
further information on this.
IIRC I did have a solid connection between the ground on the breakout
board and the star ground on the machine. Under certain conditions
that could have just made things worse.
Good luck in getting things fixed. Sounds like the machine is well
worth putting in some time and effort on.
Dave
On Dec 11, 2006, at 6:24 PM, Donald V. Lemke wrote:
Hi Nasir,
I had a similar problem using EMC1 RC_46, but it was
not a software problem. I am/was using a Motenc-100 board. The
problem was traced to encoder signals. This was about 1 1/2 years
ago. I had an X axis and Y axis using the same encoder type, and a
Z axis with a different encoder. The Z and either the X or the Y
(can not remember which one) were accurate. But the other of the X
or Y would accumulate error. This was very confusing, as an
identical axis setup was working flawlessly. I eventually tracked
down the problem by looking at signals with an oscilloscope. But, I
do not remember the specific error. Dave might remember the day
when I was on the Chat figuring this out with others helping.
This was after some PID tuning to get things working.
With PID values that are way out there was all sorts of wierd
crashing and operation. With the PID values close, the system was
stable, but there was this accumulation of error, similar to what
you say.
For those out there not familiar, Excellon is the
premier PCB drilling machine company. These machines are where all
those 1/8 inch shank drill bits are used. And also where allot of
the surplus 60 K RPM spindles come from. These machines typically
drill a stack of 4 to 6 PCB's at a time.
Nasir, is the 1 mm error on one axis or both ?
73, Don...
Subject: [Emc-users] EMC2-Motenc-Lite
Dear All.
Thanks for the previous help on the start of EMC2 with
Motenc-Lite.
EMC2 is running on P-III with Motenc-Lite PCI Card.
I/O and xy servo drive control is ok on EXCELLON EX-200 PCB
Drilling Machine,
Homming is OK
Following Small Program with G0 show approx 1mm extra travel
upon end of program each time, i.e. it contineously accumelate.
This error dose not show on the display but shows on the
slide table.
Re-Homming take out this error.
Please also advice how to tune PID Sevo Loop.
Program:
G20
G64
G0X0Y0
G0X100Y100
G0X50Y50
G0X0Y0
M2
Please reply.
Thanks
Nasir
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