Step Restrictions

To make sure the tightening stops if something unexpected happens, it is possible to add restrictions to the multistep tightening program. For each restriction, select Repairable = Yes to allow retry when tightening stops. For each of the steps in a multistep program it is possible to have up to four restrictions.

CTh – Cross Thread

This restriction checks the angle from the point where torque passes Start torque (T1) to the point where the torque passes End torque (T2). If the angle measured from Start torque (T1) is higher than Maximum limit (Amax), the tool is stopped immediately and the program jumps to the next synchronization point.

When the torque passes End torque (T2), the measured angle is checked against the limit Minimum limit (Amin). If the angle is lower than this limit, the tool is stopped immediately and the program jumps to the next synchronization point.

Parameter	Description	In illustration
Start torque	Must be <=0.	T1
End torque	Must be <=0.	T2
Minimum limit	The low angle limit.	Amin
Maximum limit	The high angle limit.	Amax

A – Maximum Angle

This restriction measures the angle. If the measured angle reaches the Maximum limit, the tool is stopped immediately and the program jumps to the next synchronization point. The angle is measured from the start of the restriction or, if specified, from the point where the torque passes Trigger torque for the first time during the restriction.

Parameter	Description
Trigger torque	If specified, this is the torque from where the angle is measured.
Maximum limit	If this limit is reached the tool is stopped immediately and the program jumps to the next synchronization point.

T – Maximum Torque

This restriction checks the torque. If the measured torque exceeds the Maximum limit, the tool is stopped immediately and the program jumps to the next synchronization point.

Parameter	Description
Maximum limit	If the torque reaches this specified limit the tool is stopped immediately and the program jumps to the next synchronization point

RH – Rehit

This restriction checks the torque. If the measured torque exceeds the Torque Limit, the tool is stopped immediately and the program jumps to the next synchronization point, or the end of the program.

Parameter	Description
Torque Limit	If the torque reaches this specified limit the tool is stopped immediately and the program jumps to the next synchronization point, or the end of the program.

RT – Rescinding Torque

This restriction checks the torque. If the measured torque is lower than the limit Torque low limit, the tool is stopped immediately and the program jumps to the next synchronization point, or the end of the program.

Parameter	Description
Rescinding torque limit	Default: 10 Nm. Must be > 0.

TG – Torque Gradient

This restriction checks the gradient and if it is outside the limits the tool is stopped immediately and the program jumps to the next synchronization point or the end of the program.

Parameter	Description
Gradient Angle Window	Specifies Angle Window: For Hard Joint: Angle Window = 20. For Soft Joint: Angle Window = 1. Manual: Manually set Angle Window.
Angle Window	Available when Gradient Angle Window is set to Manual. Must be > 0 and <= 100.
Trigger Torque	Must be > 0 and < Tool MaxTorque.
Damping	Frequency in which the gradient is being calculated. Must be > 0 and < 100 and < Angle window.
Minimum Limit	Must be >= -100.
Maximum Limit	Must be > -100 and > Low limit.
Torque Filter Type	The type of the filter: None: No filtering of the torque is used. The raw values are used as-is in the gradient calculation. Five-point: The torque value used in the calculation are filtered using a sliding average filter over 5 torque samples. Low pass: The torque values is filtered with a simple discrete Infinite Impulse Response filter. Sliding Average: The torque values used in the calculation are filtered using a sliding average filter over a Number of Samples specified by the use.
Cut-off Frequency	Needs to be specified when Torque Filter Type is set to Low pass: 20 Hz 40 Hz 90 Hz 200 Hz 600 Hz
Number of Samples	Needs to be specified when Torque Filter Type is set to Sliding Average: 2 4 6 8 16 32

TAW – Torque in Angle Window

This restriction checks that the measured torque in the angle window is within its limits. If the measured torque is outside the limits the tool is stopped immediately and the program jumps to the next synchronization point, or the end of the program.

Parameter	Description
Trigger torque	Must be >= 0
Start angle	Must be >= 0
Window length	Must be >0
Minimum limit	Must be >= 0
Maximum limit	Must be <= Minimum limit

TCD - Torque vs Current Deviation

This restriction verifies that all current measurements converted to the corresponding torque are, at most, the Maximum deviation away from the actual torque measured with the torque transducer. The restriction starts when the torque reaches Trigger Torque for the first time during the step and is active until the step reaches its target.

If Trigger Torque is never reached, the monitor will report OK.

Parameter	Description
Trigger torque	Must be >= 0
Maximum deviation	Default: 1, Must be > 0