User Manual

Control concept
Programming in D-MAP
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Plant
A plant consists of partial plants, aggregates, and components, which, as a rule,
form a supply chain with the chain links producer (here: boiler), distributor
(pre-control, heating circuit), and consumer (radiator).
Operator interventions
Commands are executed at each link of the chain through operating
interventions via HMI commands. The impact on the plant (or the process)
takes place via the corresponding function unit and automation station.
Functional units
Functional units represent the software map of chain links and plant elements.
The functional units contain all control, monitoring, and limiting functions that
are necessary for operation.
Information signals
Energy demand information can be passed on implicitly via the medium within
the supply chain, e.g., if the hot water supply temperature falls because of a
rise in heat consumption, more heat energy must be produced.
Information can also be represented by an explicit signal and transferred via a
signal path (e.g., via a bus). The following explicit signals have been defined in
the Desigo system:
Explicit signals Signal flow Application
Demand signal Consumer to producer A plant functional unit communicates its demand (that is, operating mode, set
points) to another partial plant functional unit in the direction of the producer.
The demand signal eventually arrives at the producer.
Operating signal Producer to consumer A plant informs the downstream plants about its currently effective operating
state. This signal is only used as an exception and is therefore switched
depending on the situation.
Override signal Producer to consumer The producer demands a certain operating mode from a consumer. Forced
signals are more the exception than the rule and are therefore not
implemented in sample plants. Forced signals are used for solar plants and
wood furnaces among others, where the minimum heat production cannot be
controlled.
In addition to the functional units, there are two further elements that belong to
the supply chain on the software side:
● Coordinator: The coordinator combines the demand signals of downstream
(to supply flow direction) plants and delivers a resultant demand signal to
the upstream plants. The coordinator also signalizes the operating state of
the upstream plants to the downstream plants.
● Dispatcher: The dispatcher determines the demand signals for the
producers on the basis of the resultant consumer demand signals. It
decides which and how many producers must be activated.