Mitsubishi Electric MELSEC iQ-R Series User Manual page 148

Position value per cycle after main/auxiliary shaft gear at synchronous control start
The position value per cycle after main shaft gear/position value per cycle after auxiliary shaft gear is restored as follows
according to the main input axis/auxiliary shaft operation executed before starting synchronous control.
Operation of Servo input axis
main input axis/
Absolute
auxiliary shaft
position
(Before
detection
synchronous
system valid
control start)
Home position Restoration method 1)
return
Current value Restoration method 1)
change
*1
Speed control Restoration method 1)
Fixed-pitch feed Restoration method 1)
control
Speed-position Restoration method 1)
*1
switching control
Position-speed Restoration method 1)
*1
switching control
Connection to servo Restoration method
amplifier 2)
Connection to

synchronous
encoder
Others Restoration method 2)
*1 When "[Pr.300] Servo input axis type" is either "1: Command position value" or "2: Actual position value", and when "[Pr.21] Command
position value during speed control" is "2: Clear command position value to zero" only.
*2 When the unit setting of servo input axis is set to degree, the value of servo input axis becomes the rounded value within the range of 0
to 359.99999 and the value is restored by the following restoration method 2) using the difference from the position value of servo input
axis at the last synchronous control session. Therefore, when positioning control is executed with exceeding 360 degree in the servo
input axis, position value per cycle after main shaft gear/position value per cycle after auxiliary shaft gear may not be restored correctly.
In that case, set "0: Previous value" or "1: Initial setting value of position value per cycle after main shaft gear/Initial setting value of
position value per cycle after auxiliary shaft gear" in "[Pr.460] Setting method of position value per cycle after main shaft gear"/"[Pr.461]
Setting method of position value per cycle after auxiliary shaft gear" to use.
*3 If any movement is performed along the main input axis beyond ± 2147483647 (input axis unit) from the previous synchronous control
before starting the synchronous control, the amount of change cannot be calculated correctly. In that case, set "0: Previous value" or "1:
Initial setting value of position value per cycle after main shaft gear/Initial setting value of position value per cycle after auxiliary shaft
gear" in "[Pr.460] Setting method of position value per cycle after main shaft gear"/"[Pr.461] Setting method of position value per cycle
after auxiliary shaft gear" to use.
Restoration method 1): The new value of the position value per cycle after main shaft gear/position value per cycle after
auxiliary shaft gear is calculated based on the position value after composite main shaft gear/auxiliary shaft current value.
[Main shaft]
Position value per cycle after main shaft gear = Main shaft gear ratio  Position value after composite main shaft gear
[Auxiliary shaft]
Position value per cycle after auxiliary shaft gear = Auxiliary shaft gear ratio  Auxiliary shaft current value
Restoration method 2): The movement amount from the last synchronous control session is reflected to the position value per
cycle after main shaft gear/position value per cycle after auxiliary shaft gear.
[Main shaft]
Position value per cycle after main shaft gear =
Position value per cycle after main shaft gear at the last synchronous control session + Main shaft gear ratio  Amount of
change of position value after composite main shaft gear from the last synchronous control session
5 ADVANCED SYNCHRONOUS CONTROL INITIAL POSITION
146
5.1 Synchronous Control Initial Position
Absolute
position
detection
system invalid
Restoration method
*2*3
1)
*3
Synchronous encoder axis
Incremental Absolute
synchronous synchronous
encoder encoder
[RD77MS]

Restoration method 1)





Restoration method Restoration method
*3
1) 2)
*3
Restoration method2)
Synchronous Synchronous
encoder via encoder via link
CPU device
[RD77GF]
Restoration method Restoration method
*3
2) 2)