Crosswise Data Comparison - Siemens SINUMERIK 840D sl Function Manual

05.08
5.2

Crosswise data comparison

The continuous comparison of the safety–related data in the monitoring channels
carried out in the SI monitoring clock cycle is known as "crosswise data compari-
son" (CDC).
The following apply to the axial monitoring functions: In the case of "non–steady–
state" data, tolerance values defined using machine data are used by which
amount the results of the two channels may deviate from one another without initi-
ating a response (e.g. tolerance for crosswise data comparison of actual positions).
A distinction is made between:
S Drive CDC between the drive and Motor Module (refer to Chapter 4 "Safety
Functions Integrated in the Drive").
S Axis CDC between the NCK and drive (refer to Chapter 6 "Safety Functions
Integrated in the System/Drive").
S Communication CDC between the NCK and PLC (refer to Chapter 7.2,
"Connecting I/O via PROFIsafe").
S SPL CDC between the NCK and PLC (refer to Chapter 7.3, "Safe program-
mable logic (SPL)").
Error response
If the crosswise data comparison identifies an error, then this results in a stop
response (refer to Chapter 6.3, "Safe Stops A–F").
In addition, safety alarms are output.
Note
If SGEs are quickly changed over several times this can initiate a STOP F.
Displays the crosswise data comparison clock cycle
To display the actual crosswise data comparison cycle time between the NCK and
drive, the axial MD 36992 is used: $MA_SAFE_CROSSCHECK_CYCLE and the
general MD 10092: $MN_INFO_CROSSCHECK_CYCLE_TIME. If the monitoring
clock cycle is modified, then the crosswise comparison clock cycle is also
changed.
© Siemens AG 2008 All Rights Reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
Basics on the Safety Functions Integrated in the System/Drive
5.2 Crosswise data comparison
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