Step Restrictions
The following sections describe the step restrictions available for the PowerFocus XC Controller.
To make sure the tightening stops if something unexpected happens, it is possible to add restrictions to the multistep tightening program. For each of the steps in a multistep program it is possible to have up to four restrictions.
The following restrictions are automatically added to every step that is added to the multistep tightening program.
Step Restriction | Applicable steps |
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Step Restriction Maximum Time | All except External Result and MWR |
Step Restriction Maximum Torque |
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Step Restriction Maximum Angle |
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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.
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.
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. 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 |
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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. |
T – Maximum Torque
This restriction checks the torque. If the measured torque exceeds the Maximum limit, the tool is stopped immediately.
Parameter | Description |
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Maximum Limit | If the torque reaches this specified limit the tool is stopped immediately. |
Ti – Maximum Time
This restriction checks the time. If Maximum Limit is reached, the tool is stopped immediately.
Parameter | Description |
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Maximum Limit | If this time is elapsed, the tool is stopped immediately. |
RH – Rehit
This restriction checks the torque. If the measured torque exceeds the Detection Torque, the tool is stopped immediately and the program jumps to the end of the program. It is only possible to add step Rehit restriction to the first step of the multistep tightening program. Once the Rehit restriction has been added to the first step it shall not be possible to move the step to any other position within the tightening program. The Rehit restriction has to be deleted from the first step in order to move it to other position in the tightening program.
Parameter | Description |
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Detection Torque | If the measured torque exceeds the Detection Torque, the tool is stopped immediately and the program jumps to the end of the program. Must be greater than zero. |
RT – Rescinding Torque
This restriction checks the torque and if the measured torque drops below the condition of the restriction the tool is stopped immediately and the program jumps to end of the program. There are two methods of Rescinding Torque Restrictions for Torque and Angle control processes
Parameter | Description |
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Type | Torque control processes or Angle control processes. Torque control processes: Torque control processes checks the torque. If the measured torque drops below the Rescinding Torque Limit the tool is stopped immediately and the program jumps to the end of the program. For the restriction to be active the torque must first exceed 110 % of the Rescinding Torque Limit Angle control processes: This restriction checks the maximum torque reached during the restriction. For the restriction to be active the torque must first exceed the Trigger Torque. If the measured torque drops below the maximum torque for longer time than Rescinding Torque Time the tool is stopped immediately and the program jumps to the end of the program. Cable tools have the option of choosing Rescinding Torque for Angle. This restriction is controlled by two parameters: Peak Torque Percentage and Rescending Torque Time. Percentage sets the downward deviation from the last peak torque, and Rescending Torque Time sets the duration (between 5 and 500 ms) of that deviation. Only when both conditions (equal to or lower than the indicated percentage for the set duration) are met, will the program be interrupted and jump to the end. |
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 end of the program.
Parameter | Description |
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Gradient Angle Window | Specifies Angle Window:
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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:
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Cut-off Frequency | Needs to be specified when Torque Filter Type is set to Low pass:
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Number of Samples | Needs to be specified when Torque Filter Type is set to Sliding Average:
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TAW – Torque in Angle Window
This restriction checks that the measured torque in the Angle Window Length is between the Torque limits. If the measured torque is outside the limits the tool is stopped immediately and the program jumps to the end. The Angle Window Length starts at the Start Angle from the point that the torque first passed the Trigger Torque. If Trigger Torque is not set, then the Start Angle begins at the start of the restriction.
If the end of the Angle Window Length is not reached, the status of the restriction is NOK.
Parameter | Description |
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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 |
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Trigger Torque | Must be >= 0 |
Maximum Deviation | Default: 1, Must be > 0 |
PCH - Pulse Count High
Before using Pulse Count High step restriction, it is mandatory that the following license type is installed on the controller:
Low Reaction Strategies
Pulse Count High is valid only for the following tools: ETV-STR61-100-13, ETV-STR61-70-13, ETV-STR61-50-10.
This restriction gives a limit to the number of pulses, and makes sure that those are below the specified pulse count high limit.
If the measured number of pulses is higher than the pulse count high limit, the tool is stopped immediately and the program goes to the next synchronization point or the end of the program.
If the torque trigger level is set, the check starts as soon as the measured torque is above the torque trigger level.
If running a tightening step with Pulse Count High step restriction, use the necessary PulseDrive socket/adapter.
If the tightening step runs without the PulseDrive socket/adapter, all the tightenings are NOK. The step error “PulseDrive socket/adapter not detected” shows for no PulseDrive socket/adapter.
Parameter | Description |
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Pulse Count High Limit - n+ | Pulse count high limit must range from 1 through 9999999. |
Torque Trigger - Tt | Torque Trigger must range from 0 through the maximum torque of the tool. |