Can the ATV31 be set up to operate with remote keypad command and still use an external speed pot to control the speed?
Yes. The drive can be set up to run by remote keypad to start and stop the unit while taking a speed reference from the Analog Input, AI1.
This function can be set up in the CtL menu. Set parameter LAC to L3. Set Fr1 to AI1, CHCF to SEP, and Cd1 to LCC.
See the Altivar 31 Adjustable Speed Drive Controllers Programming Manual, VVDED303042US, for details.