Originally Posted by machintek  What you have told me is that part program zero is set in the center of travel. As long as you command the machine to move within its ability to move in each axis, you should be OK. But the amount of travel is set in the parameters you mentioned.
There is a error called GROSS POSITIONING ERROR which is followed by a letter to be more specific in reason. That is a fatal error and requires a machine shut down and reboot.
Heidenhain is indicating that your error is a result of the actual position lagging behind the expected position by a value greater than allowed in the parameters.
That is why they asked you to put it in lag (which shows the difference between actual and expected position thus a value of zero at standstill) and try jogging in rapid in both directions and watching what the lag value is. Turn the feedrate down and the lag should go down.
Excessive lag is a result of too much friction (gib adjustment, bearings, lack of oil) or the motors not being able to do their job (because of a lack of energy_low voltage, or motor worn out_short brush length, or parameters set wrong_expecting more than machine can deliver).
Are you per chance on a phase converter?
Are the parameters you are putting in from the original parameter sheet that came with the machine? Assuming no control upgrades were done.
George |
George,
Thanks for the info. This morning I went and reset the software limits, following the BP manual using the metric numbers in the REF display. I then did as you suggested, went into LAG, set the feed rate to around 100 and used the joy stick to move the table. X= 4.29mm to 4.30mm in both directions . Y= 4.4 in both directions and Z was .465 going down and up was 3.9. The Z up was always faster than the Z down. I reloaded a program and again got the positioning error message. Earlier I did have a Gross Position Error A which I corrected.
I checked the auto oiler lines and they appear good. I get lots of oil on the table saddle and the Z spindle has lots of oil on it. I also followed the manual for checking the Gibbs and ways, by applying pressure on the ends of the table with the table in the +X and -X as well as the Y+ and Y-. I could feel any movement at any of the locations, although I didn't use a measuring device. You stated that the LAG is most likely the problem and that I may have to adjust the parameters to compensate. I'm going to go thru the Heidenhain manual again this morning and try a figure out which parameter/s I'll need to change. If you happen to know which ones are the ones I should look at , please let me know. Again as always, thank you for your assistance.
ben