Supply chains - Basic Documentation - RMK770-1

Communication via the KNX bus

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Air conditioning controller
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Basic Documentation
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The applications in the Synco 700 type RMU/RMH controllers consist of HVAC functional units. These functional units are based on the supply chains in buildings.

Supply chain configuration

A supply chain consists of at least one producer and one consumer, but often producer, distributor, and consumer.

  1. A producer with one distributor and one consumer.

  2. One producer with two distributors in series and one consumer.

  3. Several producers, distributors, and consumers in parallel.

The "coordinator" and "dispatcher" are defined as logical elements in the supply chain. Their role is as follows:

  • The coordinator collates the demand signals from all downstream links in the chain, and delivers the resulting demand signal to the link upstream. The coordinator also reports the operational status of the upstream links to the downstream link.

  • From the resulting demand signals of the consumers, the dispatcher determines which generators, and how many, must be enabled.

Supply chain outputs and inputs

The above illustrations of supply chains show the following:

  • Consumer: has one output to the distributor.

  • Producer : has one input from the distributor.


  • Consumer: transmits heating/refrig. demand to the upstream distributor

  • Producer: receives heating/refrig. demand from the upstream distributor.

HVAC application architecture

For a better understanding of the distribution zones for heating and refrigeration, the following extract is reproduced from document CM110057 "HVAC application architecture".

Supply chains for a room

Different consumption needs such as heating, refrigeration, and fresh air can be defined for a room.


The hot water supply chain is available for heating. The medium hot water is generated in the hot water supply system and distributed via a heating circuit; demand-based heat is then supplied to the room via a heating surface. If the heat transfer medium is air, this involves primary and secondary air handling.


The refrigeration requirement is met by the chilled water supply chain. The medium chilled water is generated in the chilled water supply system and distributed via a cooling circuit; refrigeration is then supplied to the room according to demand by means of a cooling surface. When the cooling-energy transfer medium is air, this involves both primary and secondary air handling.

Outside air

The outside air is provided by the air supply chain. The medium is treated in the air handling plant, distributed via the ducting, adapted if necessary by an air retreatment system to the requirements in the room, and discharged into the room via air diffusers.


Essentially, a plant comprises partial plant, aggregates and components, but in principle, these can equally be expressed in terms of a supply chain with the following links: energy generator, distribution (primary controller, heating circuit) and energy consumer (radiator).

Operator intervention

For each link in the supply chain, the HMI can be used for commands which affect the plant (the process) via the relevant functional unit and the automation system.

Functional units

The functional units correspond to the software mappings of the links in the chain and the plant elements. They contain all control, monitoring, and limiting functions required for operation.