Siemens SINAMICS S150 - Page 117

Safety Integrated Extended Functions
6.13 Reliable actual value acquisition with the encoder system
Safety Integrated
Function Manual, 05/2010, A5E03264275A
117
Actual value synchronization
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Figure 6-13 Example diagram of actual value synchronization
The mean value of the actual values of both encoders is calculated cyclically after actual
value synchronization (p9301.3 = p9501.3 = 1) was activated. The maximum slip defined in
p9349/p9549 is monitored within the crosswise comparison clock cycle (r9724). If "actual
value synchronization" is not enabled, the value parameterized in p9342/p9542 is used as
tolerance value for the crosswise comparison.
Two read parameters are available for safe motion monitoring:
r9730: SI Motion safe maximum velocity
Displays the maximum speed (load side) permissible due to the acquisition of actual values
for safe motion monitoring functions. The maximum velocity for actual value acquisition
depends on the actual value update clock cycle (p9311/p9511). Parameters p9311/p9511
are used to set the clock cycle time of the actual value acquisition for safe motion monitoring.
A slower clock cycle reduces the maximum permissible velocity, but also reduces the load
on the Control Unit for safe actual value acquisition.
The maximum permissible velocity which, if overshot, can trigger faults in safe actual value
acquisition, is displayed in parameter r9730.
With a default value of p9311/p9511 (0 ms), the isochronous PROFIBUS clock cycle is used
(or 1 ms in non-isochronous mode).
r9731: SI Motion safe position accuracy
Displays the greatest position accuracy (load side) that can be ensured due to the
acquisition of the actual value for the safe motion monitoring functions.
Both parameters (r9730/r9731) depend on the relevant encoder type.