Safety Functions Of The Fail-Safe Processing Unit; General Safety Checks; Check Of The Master System Data - TR-Electronic CDH 75 M Benutzerhandbuch

2.7 Safety functions of the fail-safe processing unit

The Safety Computer System (SCS), to which the measuring system is connected,
must perform the following safety checks.
So that in the event of an error the correct measures can be taken up, the following
definition is valid:
If no more data are sent by the measuring system, or if the measuring system is in
OFF condition, this is to be interpreted as safe condition.

2.7.1 General safety checks

Comparison of position data of the
master system with position data of the
safety system.
The permissible tolerance window
depends on the SSI behavior and on the
system speed and must be determined by
the plant operator first.
Cyclical consistency check of the current
master system data to the previous
master system data
Travel curve calculation and monitoring
by means of the master system
Data transmission master system and
data transmission safety system blocked

2.7.2 Check of the master system data

Error bit 1 = 1:
Master system data not safe
Error bit 2 = 1:
Safety system data not safe
Data transmission master system
blocked
Sign of life counter was not
incremented longer than 1 ms
CRC check master system data
Printed in the Federal Republic of Germany
10/11/2017
Check by SCS
Check by SCS
TR - ECE - BA - DGB - 0070 - 16
SCS error reaction
In case of exceeding of
the tolerance window -->
STOP
STOP
STOP
STOP
SCS error reaction
Definition in the SCS
Definition in the SCS
Definition in the SCS
STOP:
If the sign of life counter were
incremented or the
system data and safety system
data are within the tolerance
window, after acknowledgment
the travel can be continued.
Telegram repetition, two SCS
cycles permitted
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Necessary?
yes
yes
yes
yes
Necessary?
yes
yes
yes
master
yes
yes
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