Omron OMNUC G User Manual page 384

7-4 Manual Tuning
Other Adjustments
If the Torque Loop is saturated because of short acceleration time, large load torque, or other
causes, overshooting occurs in the speed response. In such a case, increase the acceleration time
to prevent torque saturation.
Acceleration torque
required for the
commanded pattern
Maximum
instantaneous torque
output of the Servomotor
7
Torque Control Mode Adjustment
The torque control is based on the speed control loop using the Speed Limit (Pn053) or the speed
limit value from MECHATROLINK-II as the speed limit. This section explains how to set the speed
limit value.
Setting Speed Limit Values
If the Speed Limit Selection (Pn05B) is set to 0, the setting for the Speed Limit (Pn053) will be used
as the speed limit value. If the Speed Limit Selection (Pn05B) is set to 1, the smaller of either the
Speed Limit (Pn053) or the MECHATROLINK-II speed limit value will be used.
When the Servomotor speed approaches the speed limit value, the control method will switch from
torque control using torque commands from MECHATROLINK-II, to speed control using the speed
limit value determined via MECHATROLINK-II or the Speed Limit (Pn053).
To ensure the stable operation during the speed limit, parameters need to be adjusted according
to Speed Control Mode Adjustment on page 7-16.
If the Speed Limit (Pn053) or the speed limit value from MECHATROLINK-II is too low, the Speed
Loop Gain is too low, or the Speed Loop Integration Time Constant is set to 10000 (disable), the
input to the torque limiter will be small and the torque commanded via MECHATROLINK-II may
not be achieved.
7-21
Commanded operation pattern
Overshooting occurs for the
amount of delay in command.