On 03/01/2017 07:46 AM, dragon wrote: > I have a project coming up soon that involves a retrofit of a Cel-Con > HMC. The owner has a bunch of AMC BE25A20 drives to use on it. The servo > motors are Fanuc red caps and we have some of Pico Systems' converters > that give us the hall and encoder signals from the motors. > > I have been doing a bunch of reading trying to figure out if it is > better to run the servo amplifiers in velocity mode or torque mode. Do you have DC tachometers in the motors? If not, then the only way to run the servo amps in velocity mode is to provide a synthetic tach signal to the drives, derived from the encoder. Using it with any of the Pico products, you will only get one update of the velocity every servo period, and the PPMC incurs a whole servo period delay between position sampling and DAC update (The DACs update at the next sampling of the encoder position). Also, this would take two DAC channels per axis (one for tach, one for velocity command).
So, there would be very little advantage to running in velocity mode, without real tachs (unless you get one of the encoder to tach converters that some people have built.) There used to be a great chip to do this, it hasn't been made in about 15 years. Jon ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
