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Parameters:
The following parameters are used in the screwdriving Sequence:
• Maximum time until the cut-out torque is reached (monitoring time)
• Shut-off torque,shut-off torque upper/lower limits
• RPM
• Torque holding time
• Angle measurment: yes / no
if angle monitoring is active the following parameters are added:
◦
Threshold torque for angle measurement start
◦
Angle lower limit / angle upper limit
12.1.2 Extended screwdriving to torque
The screwdriving strategy Extended screwdriving to torque is a tightening process with
shut off at a preset torque value. Angle monitoring is possible as an option.
Figure 108:
Extended screwdriving to Torque
Strategy description:
At the start of the first screwdriving sequence/step time monitoring is started and the
screwdriving process is started with RPM setting 1. Once the torque threshold for step one
has been achieved, Sequence step 2 is started and the speed setting is changed to RPM
2. Cyclic torque measurements are performed. If the angle monitoring option is active then
angle measurements are performed in additon starting at the preset torque threshold value
(sequence step 2).
Shut-off criteria:
The screwdriving process is ended once the
• target shut-off torque is achieved
• the maximum screwdriving time (time monitoring) is expired
• the maximum angle of rotation is reached (only when angle monitoring is active)
Analysis:
OK evaluation:
The screwdriving sequence is considered OK (fault free), if the shut-off occurs
via torque and the torque value is whithin the preset limits.
If the Angle monitoring option is active the final angle value must be within the
preset limits.
