WAGO 750-830 Manual page 55

3.1.4 Operating System
3.1.4.1 Boot-up
Notice
The mode selector switch may not be set at the bottom position during boot-
up!
The controller begins running up after switching on the power supply or after
a reset. The PFC program in the flash memory is then transferred to the RAM.
During the initialization phase, the fieldbus controller detects the bus modules
and the current configuration and sets the variables to 0 or FALSE, or to an
initial value specified by the PFC program. The flags retain their status. Dur-
ing this phase the "I/O" LED will flash red.
When run-up is successful, the controller switches to the status "RUN". The
"I/O" LED then stays lit continuously in green.
3.1.4.2 PFC Cycle
After successful boot-up, the PFC cycle starts if the mode selection switch is
in the upper position or due to a start command from the
WAGO-I/O-PRO CAA. The input and output data for the field bus, bus mod-
ules and the timer values are read. Subsequently the PFC program in the RAM
is processed; after that, the output data of the fieldbus and the bus modules are
written in the process image. Operating system functions, among others, for
diagnostics and communication are performed and the values of the timer are
updated at the end of the PFC cycle. The cycle starts again with the reading in
of the input and output data and the timer values.
The operating mode is changed ("STOP"/"RUN") at the end of a PFC cycle.
The cycle time is the time from the beginning of the PFC program up to the
next beginning of the cycle. If a loop is programmed within the PFC program,
the PFC runtime, and therefore the PFC cycle time as well, will be extended
accordingly.
The inputs, outputs and timer values are not updated while the PFC program is
being processed. Updating is performed only as defined at the end of the PFC
program. As a result, it is not possible to wait on an event from the process or
a set period to expire while a loop is in progress.
WAGO-I/O-SYSTEM 750
BACnet/IP Controller
BACnet/IP Controller 750-830
Operating System
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