Festo CAMC-G-S3 Manual page 265

A Technical appendix
Determination of angle difference (dynamic)
Detection of signal errors in the "shared" transmis­
sion path (resolver, SIN/COS encoder)
Position offset on "fusing" of two output semi-con­
ductors (worst case)
Position offset because microcontroller 1 and micro­
controller 2 did not sense the position at the same
time
Dynamic position offset on accelerating
Length of the compensation operation
Resulting total position difference
Tab. A.28 Observation of the possible position difference between microcontrollers 1 and 2
Monitoring the speed difference depends on the resolutions in the encoder analysis and the possible
time shift in the detection between microcontroller 1 and microcontroller 2 at maximum acceleration.
The approved filter time constant is calculated according to Section A.3.7, Tab. A.33.
Determination of total rotational speed difference (dynamic)
Resolution of encoder analysis (raw)
(important for idling detection, P06.09)
Rotational speed offset on accelerating
Time shift
Maximum acceleration
Rotational speed offset on accelerating
Resulting total rotational speed difference
Filter time constant for speed signals
Tab. A.29 Observation of the possible dynamic rotational speed difference between microcontrollers
1 and 2
Due to the high reliability (PFH) of the circuit, the maximum allowable time for encoder monitoring can
be set to 100 ms without any problems.
As a result, the encoder configuration of the safety module is parameterised as follows:
Festo – GDCP-CAMC-G-S3-EN – 1406NH – English
≤ 2 ms
approx. 60° on the shaft
approx. 1° on the shaft
typ. 30° on the shaft
typ. ≤ 10 ms
approx. 0.167 revs.
Approx. 20 rpm
Approx. 120 rpm
1 basic cycle => ≤ 200 μs
0 -> 5000 RPM within 1 ms
200 μs x 6000 rpm / 10 ms
Approx. 150 rpm
typ. 8 ms
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