# WP - Wrench Production

Tools
STwrench

Strategy used for the quality test of the tightening performed with the STwrench.

Parameter | Description
--- | ---
Control Strategy | The Wrench Production step type can be configured with the following control strategies. Torque: This strategy guides the operator is reaching the desired target torque. Angle: This strategy guides the operator is reaching the desired target angle. Torque or Angle: This strategy guides the operator is reaching the desired target angle or desired target torque. Torque and Angle: This strategy guides the operator in tightening a bolt until both target torque and angle have been reached. Yield Point: With this strategy, the STwrench detects the yield point automatically. The torque limits specify the range in which the result is OK. Target angle specifies how far beyond the yield point the user may tighten. Loose: This strategy is used to loosen a tightened screw. PVT compensate with snug: This strategy guides the operator in reaching the desired target torque for joints with prevailing torque, when the prevailing torque level is higher than the final target.

Based on the control strategy selected, a combination of some of the parameters listed below will be displayed.

Parameters | Description
--- | ---
Target Torque | Defines the target torque for tightening step.
Measure torque at | Specifies where the torque will be measured. Choose between Peak torque or Peak angle. Peak torque: The torque value will be set to the peak torque value. Peak Angle : The torque value will be set to the torque measured at the peak angle.
Angle search limit | This is an offset that is used to the set the torque result value for a tightening. Measure torque at must be set to Peak Angle for this parameter to be available.
Ratchet time | Numerical value for ratchet time which is by default 5000 ms. This allows the operator to release the torque for a while and recharge during the tightening operation. If the Ratchet time is exceeded the result of the tightening is marked as NOK with the reason "Tightening timeout".
End cycle time | Numerical value in ms to indicate the end cycle time. Applied when torque goes below the rundown complete
Torque correction coefficient | The parameter is used to correct the torque reading when using an extension or torque multiplier on the wrench. Default value is 1.
Angle correction | The parameter is used to correct the angle reading when using an extension or torque multiplier on the wrench. Default value is 0.
Target Angle | Defines the target angle for tightening step.
Rehit detection | On or Off. Rehit detection can be used to determine when a tightening is a rehit based on the angle limit setting. Angle limit for rehit is enabled if Rehit direction is set to On.
Linear slope coefficient | Linear slope coefficient characterizes the joint stiffness in the linear part of the curve, as torque/angle slope in the Nm/Deg measurement unit.
Compensate value | Choose between Average torque and Peak torque. The Compensate value specifies how the PVT will be calculated. Average torque - The PVT will be based on an average calculated using the following: Delay monitoring PVT interval PVT distance Prevailing torque min Prevailing torque max Peak torque - The PVT will be based on the peak value measured before snug was detected.
Torque Compensation | This parameter sets if the system compensates for the prevailing torque. If set to On, the system subtracts the prevailing torque from the peak torque before it reports the final torque. If set to Off, the system reports the peak torque as measured.
Delay monitoring | PVT calculation will not start before this window has been passed, starts at tightening start.
PVT interval | Sets how many degrees the PVT window shall be calculated for, start from the PVT distance point.
PVT distance | Sets how many degrees prior to snug the system shall start the PVT window.
Prevailing torque min | Prevailing torque minimum limit.
Prevailing torque max | Prevailing torque maximum limit

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WP - Wrench Production