Atlas Copco PowerMACS 4000, User Manual

Page: 193 / 668

Set Up and Maintenance
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Single torque transducer

If you are using the “Single run” option, run a program with a “Diagnostic” step with spindle
functional test enabled to get a new zero offset reading and compensation from the spindle.

Make at least 10 tightenings to the desired final torque and record the results from the reference
transducer (Xref) and the reported final torque from the spindle (X)

Calculate the mean reference torque (Xmeanref) and the mean final torque (Xmean).
Xmeanref = SXrefn / n
where “n” is the number of tightenings
Xmean = SXn / n
where “n” is the number of tightenings


Adjust the spindle parameter Scale factor for channel Torque 1 (Ts) (see Spindle Set Up,
Calibration) with the calculated value. Increase the Scale factor in order to decrease the true torque
and vice verse.
Ts-new = Ts-old x Xmeanref / Xmean

If you are using the “Single run” option, run a program with a D - Diagnostic Step in order to get a
new zero offset reading and compensation.

Run a new test series in order to confirm the correction.

If a torque scatter test is required (Standard deviation, Cp, Cpk, Cmk, CAM……) a minimum of 20
tightenings are needed.