Mitsubishi Electric MELSEC iQ-R Series User Manual page 344

Control details
Set AxisName.Pr.Drive_UnitConvRatioNum and AxisName.Pr.Drive_UnitConvRatioDen in order to output the command
value to the driver according to the specified movement amount.
The setting examples are shown below.
■For a ball screw
Ex.
When the ball screw pitch is 20 [mm], the controller command unit is [mm], the driver command unit is [pulse], and the motor
encoder resolution is 4194304 pulse/rev
Set the number of pulses required to rotate a motor once (the encoder resolution) in AxisName.Pr.Drive_UnitConvRatioNum,
and set the transfer distance of the machine per motor rotation in AxisName.Pr.Drive_UnitConvRatioDen.
AxisName.Pr.Drive_UnitConvRatioNum = 4194304 [pulses]
AxisName.Pr.Drive_UnitConvRatioDen = 20 [mm]
In this example, the movement amount per pulse is 0.00000238 [mm]. For instance, when the movement amount of 22 [mm]
is set, the command will be 4613734.4 [pulses] and a fraction of 0.4 [pulses] will appear. In this case, the movement amount
of 4613734 [pulses] is output to the driver, and the fraction is memorized inside the motion system, and positioning is
performed by adding this fraction to the movement amount at the next positioning.
■For a linear servo motor
Ex.
When the controller command unit is [m] and the driver command unit is [pulse], the number of pulses of the linear encoder
is calculated with the driver unit conversion numerator and the movement amount is calculated with the driver unit conversion
denominator.
Linear encoder resolution
Linear encoder resolution: 0.05 [m]
Number of pulses [pulse]
Movement amount [μm]
AxisName.Pr.Drive_UnitConvRatioNum = 20 [pulses]
AxisName.Pr.Drive_UnitConvRatioDen = 1 [m]
• Set the driver unit conversion multiplying factor within the following range.
|The range upper limit of the controller command value  (Driver unit conversion denominator / numerator)|
< 8000000000000000000
For the range upper limit of the controller command value, refer to the following.
Page 67 Positioning Range
If setting a value outside the range, the error "Driver Unit Change Magnification Upper Over" (error code:
1AA4H) will occur.
• A change of the driver unit conversion parameter is also imported when the PLC READY [Y0] is turned ON.
Turning ON it in the following status, otherwise, the error "Driver Unit Change Numerator/Denominator
Change Timing Incorrect" (error code: 1AA5H) will be output, and the system will be operated with the set
value before turning ON the PLC READY [Y0].
 AxisName.Md.AxisStatus is "0: Disabled"
 AxisName.Md.FollowupDisable is FALSE
11 CONTROL SUB FUNCTIONS
342
11.1 Compensation Function
Number of pulses (driver unit conversion numerator)
=
Movement amount (driver unit conversion denominator)
1 20
= =
0.05 1.0