Two different things. PWM is a drive method for the coils of a stepper motor. Reference is Output side of the driver.
PTO is Pulse Train Output. This is the clock signal sent to the controller. Each clock pulse steps the motor one step. The controller can be set for full step, half step, or microstep. Each pulse is still one step. Reference Input side of the driver.
Sir i have a doubt.. I have MLX 1400 (BXBA) ...I connected +24 VDC to VDC1(group2) and by default i am getting +22VDC in output 2,3,4(group2, FET outputs) even when i am not switching ON the output.... Is there any problem in PLC