Functions For Compensating The Control; Backlash Compensation Function - Mitsubishi Electric RD77MS2 User Manual

8.3

Functions for Compensating the Control

The sub functions for compensating the control include the "backlash compensation function", "electronic gear function", and
"near pass function". Each function is executed by parameter setting or program creation and writing.

Backlash compensation function

The "backlash compensation function" compensates the backlash amount in the mechanical system.
When the backlash compensation amount is set, an extra amount of command equivalent to the set backlash amount is
output every time the movement direction changes.
Control details
The following drawing shows the operation of the backlash compensation function.
[Pr.11] Backlash compensation amount
Precautions during control
• The feed command of the backlash compensation amount are not added to the "[Md.20] Current feed value" or "[Md.21]
Machine feed value".
• Always carry out a machine home position return before starting the control when using the backlash compensation
function (when "[Pr.11] Backlash compensation amount" is set). The backlash in the mechanical system cannot be correctly
compensated if a machine home position return is not carried out.
• Backlash compensation, which includes the movement amount and "[Pr.11] Backlash compensation amount", is output the
moment at the moving direction changes.
• Backlash compensation cannot be made when the speed control mode, torque control mode or continuous operation to
torque control mode.
Setting method
To use the "backlash compensation function", set the "backlash compensation amount" in the parameter shown in the
following table, and write it to the Simple Motion module.
The set details are validated at the rising edge (OFF  ON) of the PLC READY signal [Y0].
Setting item
[Pr.11] Backlash compensation
amount
Refer to the following for the setting details.
Page 407 Basic Setting
• Parameters are set for each axis.
• It is recommended that the parameters be set whenever possible with the engineering tool. Execution by a
program uses many programs and devices. The execution becomes complicated, and the scan times will
increase.
8 CONTROL SUB FUNCTIONS
224
8.3 Functions for Compensating the Control
Worm gear
Workpiece
Setting Setting details
value

Set the backlash compensation amount.
Factory-set initial value
0