Dave wrote: >> There is likely a command that you can send to the encoder to zero or >> preset the encoder. Some systems call that a passive homing routine. >> Yes, that seems very reasonable, but I have no idea how to find out what code to send to the encoder to make it home on index. It was hard enough to figure out how to make it report the position. >> Absolute encoder systems can be really handy on machines that are >> difficult to home with a conventional home switch search. >> I can see this on robots, but it doesn't seem all that big a deal on conventional machine tools. >> If the encoder always knows where the rotor is at (since the encoder is >> absolute), isn't commutation pretty simple after the initial angle >> setting of the rotor position? >> Well, I'd like to skip the battery if I could. But, if the encoder has no idea where it is, and just calls the location on power-up zero, then commutation is NOT simple. Apparently, it may provide the 4-bit Gray code commutation that has been used on earlier Fanuc brushless encoders in that state. That would at least allow the motor to operate. Then, it may send some useful signal when it passes the index position. But, if the encoder is only sampled once per ms, the "index has been seen" indication is not very precise. Hopefully, Fanuc does something more intelligent with it.
Jon ------------------------------------------------------------------------------ WhatsUp Gold - Download Free Network Management Software The most intuitive, comprehensive, and cost-effective network management toolset available today. Delivers lowest initial acquisition cost and overall TCO of any competing solution. http://p.sf.net/sfu/whatsupgold-sd _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
