User Manual

Control concept
Superposed plant controls
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Prior to switching on a block a test is made to see if the conditions for executing a command are given. The
switch-on process is not even available for active switch on delay, minimum switch off times or a switch
command with a higher command (e.g., a maintenance switch). This Look Ahead mechanism is described
in greater detail in this chapter.
This block does not contain interlocks of individual functional units within aggregates. These are
implemented locally via the data flow between the relevant blocks.
Plant Control Editor
The block parameters are set in the Plant Control Editor.
The upper part of the dialog box serves primarily to provide a quick online overview of the present plant
operating mode. You can also define exception value which become active as a plant operating mode
during a plant fault.
The upper part of the table configures the sequences. The switch-on sequence of the objects, the
monitoring mode and the switch on and off types for the sequence controllers can be defined here.
The lower part of the table is used to define the plant operating modes. You can define what command at
what priority is command per plant operating mode for each sequence element.
The following priorities for commanding are available:
● Priority 2: Life safety, automatic
● Priority 5: Plant safety, automatic
● Priority 14: Specific command object
● Priority 16: System control
You can enable a command priority with the value Not command for plant operating modes where the local
control is intended to assume control of the aggregate.
[DefVal] applies when the [PrioArr] for the corresponding block is empty, that is, not active recognition set,
at that time.
Function workflows in CMD_CTL
A series of safety, monitoring and switch actions are conducted for each change to the plant operating
mode in block CMD_CTL.
Stage Function Action
1 Safety function Check AllLifeSafety plant operating modes.
2 Preview Checks if the aggregates in question can be switched.
3 Abort sequence Incomplete sequences are interrupted.
4 Reset sequence Switch off unneeded aggregates.
5 Step-up sequence Switch on the newly needed aggregates.
6 Monitor switch-on states Start monitoring of countdown of delay period.