Atlas Copco PowerMACS 4000, User Manual

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Tightening
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Diagram: (with Stop condition SO)
Angle
Torque Gradient
Gradient
Torque
T Start
A dist
A dist
Shut off point
Max gradient
YAL
YAH
T Start Torque start A dist Angle distance
YAH Yield point angle high DIFF Difference %
YAL Yield point angle low
Step
YP Angle
DIFF * Max gradient
Yield point
Result var.: "YP Angle" (Yield Point Angle), the angle between the Yield point and the end angle.
Alarms: Yield Point Angle High (YAH) and Yield Point Angle Low (YAL)
Trace : No limits are shown in trace.
6.5.4.14 Check Stick Slip
Parameters: Trigger mode, Max drops, Trigger level, Threshold torque.
Function: This check detects and reports stick slip effects during a step. The detection is done by
counting the times the torque falls below the level TTrig and if the number of times is larger
than Max drops the stick slip error is reported.
The check operates in two different modes, Dynamic or Fix. The difference between the
modes is the way TTrig is calculated.