Atlas Copco PowerMACS 4000, User Manual

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Tightening
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6.5.3.4 Min Torque Restriction
Parameters : Threshold torque TStart, Min torque limit MinT
Function : The restriction starts when the measured torque passes TStart. After this the step is
stopped immediately if the measured torque falls below the level MinT. The restriction is
only active until the control function of the step has shut off, since the torque normally drops
when the spindle is stopped.
Note that the restriction is not active during the torque spike elimination phase in the
beginning of the step. The search for TStart starts then the torque spike elimination is
finished.
Diagram 1:
Angle
Torque
Step
TStart Threshold Torque
MinT Min Torque Limit
TStart
MinT
Restriction active