Mitsubishi Electric D75D4, User Manual

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12 - 29
MELSEC-Q
12 CONTROL SUB FUNCTIONS
12.4.2 Torque limit function
The "torque limit function" limits the generated torque to a value within the "torque limit
value" setting range when the torque generated in the servomotor exceeds the "torque
limit value".
The "torque limit function" protects the deceleration function, limits the power of the
operation pressing against the stopper, etc. It controls the operation so that
unnecessary force is not applied to the load and machine.
The QD75 does not carry out the torque limit of servo motor directly with this function.
The torque limit command to servo amplifier is carried out by the D/A converter
module.
The details shown below explain about the "torque limit function".
[1] System configuration for carrying out the torque limit
[2] Relation between the torque limit function and various controls
[3] Control details
[4] Control precautions
[5] Setting method
[1] System configuration for carrying out the torque limit
Carry out the torque limit in the configuration in the figure below. (The following
modules are required.)
 D/A converter module

Drive unit capable of torque limit control by analog voltage input
CPU module QD75 Drive unit
Positioning
control
3) Torque limit
1) Reading data
by the FROM
instruction
2) Writing data
by the TO
instruction
D/A converter module
826 Torque limit stored
value
Buffer memory
1) Read out the " Md.35 Torque limit stored value".
2) Write the value read in 1) into the D/A converter module.
(The value must be converted according to the specifications of D/A
converter module.)
3) The drive unit carries out the torque limit according to the voltage
input from the D/A converter module.
Fig. 12.16 Torque limit to the drive unit (axis 1)