Fieldbus coupler/controller
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Review
Modular I/O System
L
ON
W
ORKS
®
3.2.4 Operating system
3.2.4.1 Start-up
The controller starts-up after switching on the supply voltage or after a hard-
ware reset. The PLC program in the flash memory is transferred to the RAM.
This is followed by the initialization of the system. The controller determines
the I/O modules and the present configuration. The variables are set to 0 or to
FALSE or to an initialization value given by the PLC program. The flags re-
tain their status . The "I/O" LED blinks red during this phase.
Attention
PFC program variables that are linked with network input variables are also
set to 0 or to FALSE after reset, even if they are defined in the retentive me-
mory area or as a flag.
Therefore, variables used for external configuration via LON fieldbus must
be linked with CPs (Configuration Properties).
i
More information
You can find detailled information on the Configuration Properties (CPs) in
Chapter 3.2.6.1 "Memory areas" and Chapter 3.2.6.2.3 "Addressing the con-
figuration variable".
Following an error free start-up, the controller changes over to the "RUN"
mode. The "I/O" LED lights up green.
In the delivery state the flash memory is blank therefore no PFC program is
included.
Attention
An application program in accordance with IEC 61131-3 is absolutely neces-
sary for the fieldbus controller to operate. The data of the bus modules need
to be copyed into the PFC variables (fieldbus variables) via the IEC 61131-3
application program, in order to be used.