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 Desigo Cybersecurity Guidelines Application Guide (A6V14142297).
  • 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 carried out 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.

Values read in cycle 1 are processed in cycle 2. Output values calculated in cycle 1 are transferred to the peripherals in cycle 2.