First guess..... your encoder signals are connected in the opposite
phase from that needed for your motor connections. Try swapping
the A and B channels of the encoder or the + and - wires to the
motor, but not both.
Second guess..... your encoders do not have a shared ground
reference with the inputs of the G320X. The ground of the encoder
power must be connected to the ENC GND on the G320X even when
using an external power source.
Third guess.... your encoders are not making valid signals. You should
be able to measure the output voltage of each phase (A, B) to ENC GND
using a regular meter by removing the motor wires and very carefully
moving the shaft of the motor by hand. With some practice you should be
able to stop the shaft with the signal at 0 volts and at near 5 volts on each
signal. This will prove that the electrical output is valid.
