# PrT - Prevailing Torque

The monitor calculates the prevailing torque value in a defined angle Window Length in order to subtract the prevailing torque value from the tightening's absolute peak torque value.

The angle Window Length, in which the prevailing torque value is calculated, starts at the angle degrees set in Start Angle Distance measured in reverse direction from the snug point, which is automatically calculated by the system in real time. The angle window then spans in opposite direction for the angle degrees set in Window Length. The calculated prevailing torque value can be either the mean or the peak torque value measured during the Window Length according to the Use value set for the tightening operation. If Compensation is set to On, the calculated prevailing torque value is subtracted from the absolute peak torque value, and the torque final result value is the difference between the torque peak value and the prevailing torque value.

Parameter | Description
--- | ---
Delay monitoring | Angle value after which the angle reading must start. This parameter is used filters the angle reading making it start after a certain angle value at the beginning of the tightening.
Start Angle Distance | Angle value that, spanning in reverse direction from the snug point, defines where the angle Window Lenght starts.
Window Length | Angle interval during which the compensate value is calculated.
Compensation | Method to define the tightening result: On: the torque result value is the difference between the torque peak value and the calculated prevailing torque value. Off: the torque result value is the absolute peak torque value.
High Limit | Upper torque limit value to get an OK result. High Limit must be > 0
Low Limit | Lower torque limit value to get an OK result. Low Limit must be ≥ 0
Use value | Method to define how to calculate the prevailing torque value in the angle Window Length interval: Mean torque: the mean torque calculated during the Window Length is taken as prevailing torque value. Peak torque: the peak torque measured during the Window Length is taken as prevailing torque value.

This step monitor can be used only with the tightening step TM - Manual Tighten to Torque.

Relevant Information

- Torque (Control) / Prevailing Torque (Monitor)