• Calculate the speed command so that the difference between the number of pulses of the internal pulse train (if Pr.419 =
"0", command pulses are used in the inverter from the number of pulses defined by parameters (Pr.465 to Pr.494)) and
the number of pulses in the feedback from the motor terminal encoder (estimated value when PM sensorless vector control
is used) is 0, and then rotate the motor based on the calculation.
1) Once a pulse train is input, pulses are accumulated in the deviation counter, and the droop pulses in this counter
become position control pulses and speed command.
2) When the motor starts to rotate in response to the speed command from the inverter, feedback pulses are also
generated by the encoder at the same time. Subtract the encoder feedback pulses or feedback estimate value from the
droop pulses in the deviation counter. The deviation counter keeps rotating the motor while keeping a certain droop
3) If the command pulse input stops, the amount of droop pulses in the deviation counter decreases and thus the speed
slows down. When there is no droop pulse, the motor stops.
4) If the number of droop pulses becomes smaller than the value set in Pr.426 In-position width, the system determines
that positioning is complete and the In-position (Y36) signal is turned ON.
Motor speed [r/min]
Command pulse frequency [PPS]
• The pulses are slow during motor acceleration and fast at full speed. The pulses become slower during deceleration, and
eventually reach 0 and the motor stops a little after the command pulse.
This time difference is necessary to ensure stop accuracy and is called stop setting time.
• To assign the Pre-excitation/servo ON (LX) signal, set "23" in any of Pr.178 to Pr.189 (Input terminal function selection).
• To assign the In-position (Y36) signal, set "36" in any of Pr.190 to Pr.196 (Output terminal function selection).
• Changing the terminal functions with Pr.178 to Pr.189 and Pr.190 to Pr.196 may affect other functions. Set parameters after
confirming the function of each terminal.
Parameters referred to
Pr.178 to Pr.189 (input terminal function
Pr.190 to Pr.196 (output terminal function
Droop pulse value
Pulse train Rough
5.5 Position control under vector control and PM sensorless vector control
Stop settling time