Atlas Copco PowerMACS 4000, User Manual

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Tightening
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6.5.2.3 DT3 - Run until Dyna-Tork
TM
, method 3
Step type Id: 35
Parameters : T (Torque), TI1 (Time1), TI2 (Time2), PERC (Current percentage), DIR (Direction).
Function : Run spindle, in DIR direction, until torque is T using transducer 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 starts the torque DT is converted to a corresponding motor current using the
spindle parameters
T/C Factor, T/C Correction Factor and Gear ratio . The first part of the
step runs using transducer control. When the torque measured on the torque transducer
used for control reaches T the step switches to current control using the current that
corresponds to DT as set point for the motor servo. This current is then 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.
Result var .:
This step produces the step level result variables “DT T”, "DT Mean T" and "Relax A".
"DT T" is the torque measured when the torque set point is switched to DT.
"DT Mean T" is the mean torque measured during the second time interval (TI2).
"Relax A" (relaxation angle) is the angle that the bolt moves during the time interval
TI1 + TI2.
Trace : Torque T 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).