User Manual

Automation stations
Functions
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18 Automation stations
The Desigo PX range is based on freely programmable automation stations. They provide the infrastructure
to accommodate and process system-specific and application-specific functions. The PX range of
automation stations comprises the compact and modular series.
See
Desigo PX - Automation system for HVAC and building services - System overview (CM110756).
See
Automation stations modular series PXC..D, PXC..-E.D, PXA40-.. (CM1N9222).
See
Automation stations compact model PXC..D (CM1N9215).
Control Functions
The D-MAP programming language lets you program and parameterize plants, using function blocks and
compounds. The graphics-based data-flow programming in Xworks Plus (XWP) lets you implement all the
necessary control strategies for optimum operation.
System Functions
The distributed functions, which ensure the overall functioning and inter-operation of all plants, are
described in the following chapters and documents:
● For alarm strategy, see chapter
Alarm Management .
● For time scheduling, see chapter
Calendars and Schedulers .
● For access rights and user designations, see
IT Security in Desigo Installations (CM110663).
● For emergency operation and forced control, see chapter
Control Concept .
● For wiring tests with Desigo Point Test Tool, see chapter
Desigo Workflow, Tools and Programming .
Cyclical Processing
One PX automation station contains one downloaded D-MAP program. A D-MAP program cannot run on
two automation stations, that is, there are no overlapping programs across automation stations. A
downloaded D-MAP program does not run automatically. It must be started explicitly and is executed in
accordance with the cyclical processing principle, that is, all D-MAP blocks in an automation station are
processed in a repeating cycle.
Cycle time
A minimum and maximum cycle time is defined for each automation station. If the processing of all blocks
is:
● Shorter than the minimum cycle time, the next processing cycle is delayed until the minimum cycle time
has elapsed.
● Longer than the maximum cycle time, the next processing cycle starts as soon as possible.
The processing order of the individual blocks:
● Does not depend on their arrangement on the plan (D-MAP program)
● Can be set explicitly when creating the D-MAP program
Process image
The values at the physical inputs and outputs are displayed in the automation station via the process
image. There are two instances of the process image:
● The frozen process image does not change during a processing cycle. D MAP programs only read from
or write to this instance of the process image.
● The active process image is continuously connected to the real plant.