Delay time
- Menu: 4.6.5-1.2
Description
The speed setpoint (parameter Speed of the parameter group Setpoints > Setpoint value connection) can only be reached if the drive can provide sufficient torque to move the load. When the torque limit is reached, the inverter assumes that the speed setpoint can no longer be reached. If this status continues for the duration of the specified delay time, the speed monitoring function triggers an error. The delay time can be used to control that no error is triggered when the torque limit is reached for a short time, e.g. in acceleration processes, deceleration processes or load peaks. Once the torque limit has been reached, a counter counts the duration for which the torque is at the limit. The counter is decremented after the torque limit has been exceeded. The parameter Reset time factor specifies how quickly the counter is decremented when the limit value is left compared to incrementing.
The parameters Speed monitoring motor mode – active and Speed monitoring generator mode – active (parameter group Diagnostics > Status > Signals) indicate whether speed monitoring is active.
In V/f operating mode, slip is monitored instead of the motor speed/speed.
SEW‑EURODRIVE recommends to always activate speed monitoring and to set the delay time to the smallest possible value.
INFORMATION
Speed monitoring is not safety-relevant.
CV | Count value |
t | Time |
CV1 | Count value that corresponds to the specified delay time |
When the torque limit is reached (time period marked in color in the diagram), a count value is incremented every millisecond. If the count value reaches the value CV1, speed monitoring triggers an error.
CV | Count value |
t | Time |
CV1 | Count value that corresponds to the specified delay time |
If the torque limit is left before the count value CV1 is reached (time period marked in color in the diagram), the count value is decremented until 0 is reached depending on the setting of the Reset time factor parameter. With a factor of 1, the count value is reduced by 1 every millisecond (diagram [1]), with a factor of 2 every millisecond by 2 (diagram [2]), etc. The count value cannot be negative.
CV | Count value |
t | Time |
CV1 | Count value that corresponds to the specified delay time |
If the torque limit is reached again before the count value is reset to 0 (time period marked in color in the diagram), counting continues with the current count value.
