TR-Electronic CDH 75 M - Principle of the Safety Function

General information
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Page 64 of 108 TR - ECE - BA - DGB - 0070 - 17 12/13/2018
1.3.2 Principle of the safety function
System safety results when:
– the control compares the position of the two measuring systems with each
other and introduces appropriate safety measures in case of inadmissible
tolerances. The safety measures are to be defined first by the system
manufacturer.
– the control additionally checks the correctness of the position information in
each SSI telegram due to the following error information:
1. Error bit of the master system and safety system (self-diagnosis)
2. Sign of life counter
3. CRC checksum
When errors are detected the control introduces appropriate safety
measures defined by the system manufacturer.
– the control additionally checks whether the obtained position data lie in the
position window expected by the control. Unexpected position data are e.g.
position jumps, tracking error deviations and incorrect direction of travel.
– the system manufacturer ensures, through correct mounting of the
measuring system, that the measuring system is always driven by the axis
for measurement and is not overloaded
– the system manufacturer performs a verified test during commissioning
and in the event of any changes of the counting direction