Chapter 1 Principles Manual VIPA CPU 21x
1-6 HB103E - Rev. 05/45
Function security of the VIPA CPUs
The CPUs include security mechanisms like a Watchdog (100ms) and a
parameterizable cycle time surveillance (parameterizable min. 1ms) that
stop res. execute a RESET at the CPU in case of an error and set it into a
defined STOP state.
The VIPA CPUs are developed function secure and have the following
system properties:
Event concerns Effect
RUN → STOP
general
BASP (Befehls-Ausgabe-Sperre, i.e. command
output lock) is set.
central digital outputs The outputs are set to 0V.
central analog outputs The voltage supply for the output channels is
switched off.
decentral outputs The outputs are set to 0V.
decentral inputs The inputs are read constantly from the slave and
the recent values are put at disposal.
STOP → RUN
res. Power on
general First the PII is deleted, the call of the OB100
follows. After the execution of the OB, the BASP is
set back and the cycle starts with:
Delete PIO → Read PII → OB1.
central analog outputs The behavior of the outputs at restart can be
preset.
decentral inputs The inputs are read constantly from the slave and
the recent values are put at disposal.
RUN general The program execution happens cyclically and can
therefore be foreseen:
Read PII → OB1 → Write PIO.
PII: = Process image inputs
PIO: = Process image outputs