05-15-2010, 05:57 PM
|
 | | | Join Date: Apr 2004 Location: USA Age: 35
Posts: 47
| |
Incorrect actual joint movement | |
I have a j-head b-port that I am retrofitting the original anilam controls with emc2 and mesa 5i20 and 7i33 boards. The machine uses the original anilam/ accurite linear encoders for feedback. I've got the machine running very well at this point and have gotten past the regular servo tuning issues. My issue is with actual machine movement versus commanded machine movement.
I will focus on the z-axis for now, because the encoder resolution is still readable on the linear encoder. The label reads .0005". Which would make the input scale 2000. These settings cause a grossly innacurate movement on the z-axis. If I command a jog of 1", the axis only moves .885" or so, but the dro readout reads in .0005 increments. If I change the input scale to 2539, the axis moves 1" when comanded. But when i command a 2" movement it stops short by about 3 or 4 thou. Also the dro in axis reads in .0004 increments (which really bothers me for some reason.)
Cliff notes:
An input scale corresponding to actual glass scale resolution of .0005" (2000) produces a move that is short by .200" or so. But results in dro display of
.0005 increments (which is the way i like it)
An input scale of 2539 gets me really close to a 1" movement, but seems to be off at 2" movement. But also gives me .0004" increments in axis dro.
What am i missing here? has everyone else had to modify what they think is the right input scale to adjust for the actual posistion of the movement? I guess I can live with increments of .0004" instead of .0005", but it just looks and seems wrong to me.  |
Similar Threads 
Linear Mode
