Mitsubishi FR-A800 Instruction Manual page 230

Operation example
• 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
amount.
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 positioning completion signal (Y36) is turned ON.
Motor speed [r/min]
Command pulse frequency [PPS]
STF (STR)
Forward (reverse)
Y36 signal
In-position signal
• The pulses are slow during motor acceleration. The pulses are fast at full speed. The pulses become slower during
deceleration, and eventually becomes 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.
NOTE
• To assign the servo ON signal (LX), set "23" in any of Pr.178 to Pr.189 (input terminal function selection).
• To assign the positioning completion signal (Y36), set "36" in any of Pr.190 to Pr.196 (output terminal function selection).
• Changing the terminal assignment using Pr.178 to Pr.189 or 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 selection)
Pr.190 to Pr.196 (output terminal function selection)
Position control under vector control and PM sensorless vector control
Droop pulse value
Acceleration
Pulse train Rough
LX signal
Servo on
page 430
page 384
Motor speed
Pulse distribution
Deceleration
Fine Rough
Time
Stop settling time
229
PARAMETERS
5