[daedalus]

Hi,

Im having problems getting the VSD-A drive working with a small brushless linear motor. What i am unsure of is how to calculate the pole count / rev and cpr of the encoder. Basically i have an encoder that gives me one pulse per 0.5 um, and the magnetic poles are 1 1/8 inch apart (1 inch magnet + 1/8 inch gap between). The forcer is just 3 coils of wire.

I am assuming that in this application you would want to go for 2 pole, and set the encoder cpr to the number of encoder counts in 2 1/4 inch. The problem with doing so is that the software doesnt allow cpr to be set that high. Is it possible to set higher limits by issuing spi commands manually?

The other issue i am having is due to the design of the assembly the motor is in, as i only have just over 1 inch of travel, so phase search fails every time. Is there a way to limit phase search to less then one "rotation"? I can fix this issue by remounting the motor on a longer travel, but if theres a workaround for testing it would be very helpful. Also am i right in assuming that this issue would go away with a vsd-e as i could use hall effect sensors?