Good to hear from you. You shoule put the EtherCAT drive into CSV (speed mode) then it is possible to combine the EtherCAT axis with the encoder wheel as feedback.
BASE(wheel)
ATYPE = 44 ' (servo axis type)
UNITS = UNITS AXIS(ecat_servo)
DAC_SCALE = 0
ADD_DAC(wheel) AXIS(ecat_servo)
ADDAX(ecat_servo) AXIS(wheel)
When you want to use the wheel, set this:
DAC_SCALE AXIS(wheel) = 1
DAC_SCALE AXIS(ecat_servo) = 0
When you want to use the motor'd encoder, set this:
DAC_SCALE AXIS(wheel) = 0
DAC_SCALE AXIS(ecat_servo) = 1
Your P_GAIN and VFF_GAIN for each axis will need to be tuned and set up. They will be different values because the counts from the encoder for each mm will be different for each feedback source.