Paul Keeton wrote: > Thanks Robert, > > Do you know if anyone might have used the old Fanuc > drives? If I could reuse mine it could save a big bundle! > > The problem with a Fanuc retrofit is that they generally provided synthesized tachometer signals from the control. The velocity servo amps need a velocity feedback signal to close the velocity loop, and most Fanuc motors don't have tachometers.
So, there are a couple ways to do it. You can add a DC tachometer belt driven off the motor shaft. There is a guy in Bulgaria, I think, that is making a dual-channel encoder to tach converter for 100 Euros. Or, you could rig a HAL component that produced a tach signal from the encoder raw delta and sent it out a DAC channel. The Fanuc servo amps can also be switched to torque mode operation. This would require some re-tuning of the drive itself. As for analog velocity servo interfaces, there is the Pico Systems PPMC (that's me) and Mesa. You'd need two DAC channels per axis to go this way, one for velocity command and one for synthetic tach. You'd want to make sure your encoders have plenty of resolution to make this work well. Jon ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
