PCL
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Pleiger Control Loop
Manual version 2018-03
10.4.2 Symbol explanation for the connection to PLD
A PLD can only have a activ connection to one busmaster of the busmaster pair. To the other bus-
master exist only a limited connection to know if the busmaster is alive. All connected PLD have the
activ connection to the same busmaster.
The comunication between busmaster and PLD is faulty.
The communication between busmaster and PLD is OK.
The PLD has full connection to this busmaster.
The PLD has no full connection to this busmaster.
Table 10-3: Symbolization of the PLD connection states
The request for the full connection correlates with the active connection to the SCADA system. The
SCADA system selects the active connection between busmaster A and B. The busmasters A and B
only have to select the request if the SCADA system is not connected. To select the request they use
the CAN bus connection. If this connection is defect, too, the operator has to set the request via PLD.
In this case there is a button highlighted for each busmaster.
If the button
is pressed at one PLD the request is set in the busmaster. All PLD activate
the connection to this busmaster.
Figure 10-34: PLD with passive connection to both busmasters
In this constellation you can switch over the full connection to the passive busmaster. This is neces-
sary if the connection to the active busmaster is defect at one PLD and you want to control the system
from this PLD.
Figure 10-35: PLD with selected connection to one busmaster and passive to the other
