Atlas Copco PowerMACS 4000, User Manual

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Tightening
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6.5.2.1 DT - Run until Dyna-Tork
TM
Step type Id: 1
Parameters : T (Torque), TI1 (Time1), TI2 (Time2), PERC (Current percentage), DIR (Direction).
Function : Run spindle, in DIR direction, until torque is T using current control. When the target is
reached a new torque, DT, is calculated as
DT = T * PERC / 100
The torque DT is then retained during the next TI1 + TI2 seconds using current control.
The PERC parameter makes it is possible to Dyna-Tork
TM
at a lower level than the target.
Before the step is started both torques, T and DT, are converted to corresponding motor
currents using the spindle parameters
T/C Factor, T/C Correction Factor and Gear ratio .
When the step starts the current that corresponds to T is set as current reference to the
motor servo. When the servo reaches this current the step immediately switches the current
reference to the current that corresponds to DT which then is maintained for TI1 + TI2
seconds.
Note: To avoid overheating of the spindle it is strongly recommended to never run Dyna-
Tork
TM
to more than 40% of the maximum torque of the spindle.
Diagram :
Time
Torque
TI1
TI2
T Torque TI1 DynaTork Time 1
PERC Percent of T TI2 DynaTork Time 2
DT Torque level retained during TI1 and TI2
T
Step
DT
(PERC = 100%)
DT
(PERC = 80%)