richard harris wrote: > This code has more linear inches of motion and is longer than the program > that was exhibiting issues. > I ran it three times without the coolant or spindle running, i had two other > machines running at the same time as i did the other day. I also had halmeter > showing the encoder count, not sure if it would show anything of value but i > was curious. The machine repeated within the tolerance of the indicator.. > I then ran it three times with the coolant and spindle running and witnessed > two thousands of motion lost over the three runs. However Halmeter showed > the same number of encoder counts. > I think halmeter will ALWAYS show the same count, as EMC will always move such that at a particular commanded position, the count will be the same. The problem is that the encoder is presumed to actually be at a different position than EMC is seeing. > I am assuming two things, 1 my problem is noise, 2 the error was less during > the test because i did not load the spindle. Do those sound like reasonable > assumptions? > I agree strongly with #1, not sure about #2. The different program may have a lot more to do with it than the spindle load. But, you could also be quite right. Do you have a VFD on your spindle? These are VERY noisy devices. Make sure there is a good ground conductor between the VFD and the motor frame. You may need to put a noise filter on the line input to the VFD. If the spindle motor wires and VFD supply wires run near any other wires, suspend them away from other wiring and rerun this test. > My plan at the moment is get a differential receiver on all the encoders, and > run new wires on the x-axis just in case. If these mods don't improve the > situation I'm thinking of adding a line reactor to the VFD. > Any other straight forward things I can do to improve the noise situations? > A line reactor, by itself may not help much (or it might). A complete EMI filter is a better way to go. You may be able to find one at a surplus store. The kind used to protect a rack of computers is the sort that works best in these cases, I have one on my mill's VFD.
The differential receiver should help, but good noise control practices are still important. Jon ------------------------------------------------------------------------------ The Planet: dedicated and managed hosting, cloud storage, colocation Stay online with enterprise data centers and the best network in the business Choose flexible plans and management services without long-term contracts Personal 24x7 support from experience hosting pros just a phone call away. http://p.sf.net/sfu/theplanet-com _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
