Atlas Copco PowerMACS 4000, User Manual

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Tightening
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6.5.2.9 Y2 - Run until Yield point, method 2
Step type Id: 8
Parameters: TC (Torque TC), NOS (No degrees), NNOS (No of points), TDIFF (Torque difference),
RNOS (No of points ref), DIR (Direction).
Function : Run spindle, in DIR direction, until the yield point. Search for the yield point starts when the
torque has reached TC. The average of the torque over NOS angle degrees is calculated.
This procedure is repeated RNOS times. A reference slope is calculated with linear
regression over the RNOS points. After that, new average values are continuously
calculated over NOS degrees. The actual slope is calculated with linear regression over the
last NNOS average points. The yield point is reached when the actual slope is less than
TDIFF % of the reference slope.
Diagram :
Angle
Torque
TC Torque, TC NNOS TDIFF
NOS No. degrees RNOS
TC
RNOS
NNOS
Reference slope
Actual slope
Step
1: NOS
1
1
1
1
1
1
1
1
1
1
1
1
Trace : Torque TC is shown as a horizontal line from step start to step stop in trace when Torque
vs. Time is selected. Control parameters must be enabled in the trace form (see
View of
trace curves).