Technical data

The following figure (Fig. 9.6) illustrates one way of integrating the HDBs in
the cold or warm restart branch of the PLC.
Both in the cold restart branch (OB 20) and in the warm restart branch
(OB 21/22) each CP interface to be used later must be synchronized
(SYNCHRON HDB). From the cold restart branch, the PLC operating
system branches directly to the first cycle checkpoint. The process image of
the inputs (PII) is read in for the first time at this point. The first RECEIVE
synchronization point for the CP 5430 TF/CP 5431 FMS is therefore already
in the cold restart branch. At this point (i.e. at the end of OB 20) the CP can
also be monitored to check that the GP image is complete. For this
purpose, the CONTROL HDB can be integrated and called in a loop
repeatedly until the CP no longer signals an error in the GP image using
the control status word.
(OB 20, OB21, OB 22)
With this HDB call (job number
201), the station list is read in
by the CP 5430 TF/CP 5431 FMS.
The station list contains the
statuses of the CPs of all active
stations on the bus from which
input GP is expected.
HDB SYNCHRON call for the SSNR
of the CP 5430 TF/CP 5431 FMS
yes
GP of
stations
1and 2 ok?
no
end
Synchronization of the interface
PLC-CP 5430 TF/CP 5431 FMS
Evaluation of the station list
i.e. interrogation of the statuses
which should have started up
(here, stations 1 and 2).
HDB RECEIVE call with
ANR 211
HDB RECEIVE call with
ANR 201
Fig. 9.6: HDBs in the Cold or Warm Restart Branch of the PLC
B8976060/02 Communication with Global I/Os
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