B
DTRen-2008/SPA-5/LVA
Rev.:
a
Page 31
Bombardier Transportation (ZWUS) Polska Sp. z o.o.
4.4.5 EMB-10 Safety Breaker Module
The safety circuit-breaker module is responsible for reliable cutting off the signals
which control the safety critical devices if any critical failure in the LX system
control unit occurs.
The safety circuit-breaker is activated from both control channels by the
rectangular wave (OutGen1A and OutGen1B) generated by the PLC A and PLC B.
Signals generated in PLC A (OutGen1A) pass through the whole hardware
structure of the EMB-1 module and are directed as a feedback (InGen1B) to the
digital inputs of the adjacent PLC B. The same is done with rectangular wave
generated by PLC B.
If EMB-10 works correctly then as long as both controllers operate correctly and
rectangular waves are transmitted to the EMB-10 the output signals from EMB-10
(galvanically separated UA and UB voltage) supply input/output modules of PLCs
responsible for the operation of the safety critical functions. In case of any EMB-10
hardware failure or in case of any PLC software critical failure rectangular waves
will be distorted and it will result in cutting-off of the EMB-10 output signals Ua and
Ub and cutting-off feedback signals to PLCs. Lack of power supply of the PLCs
input/output cards causes that warning devices go the strictly defined status which
is treated as safe. Normal program operation of PLCs will be stopped. As a result
LX system will fall to the safe state from which the only way-out is via manual
restart of the system.
EMB-10 Safety Breaker module and its location in the whole LX system
architecture.
Figure 19
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