Connection of Vitotronic controllers to the Modbus network
The next project to integrate boiler equipment, this time from Viessmann. The object is a design center, the trade and exhibition complex Artplay in Moscow.
Composition of equipment:
Vitotronic 300-K Typ MW1B -1pc.
Vitotronic 100 Typ GC1B -3pcs.
This system uses the so-called "cascade control". The three hundredth controller is the master controller, and the hundredth ones are slave controllers, serving each of the boilers. All controllers have ports for connection to the LON-network, which are connected to each other by a common bus. The customer wanted to monitor about twenty parameters in the Modbus network for further dispatching.
Having no experience in integrating this equipment, the task may seem quite typical - by analogy with previous projects to draw the necessary output parameters from the functional blocks of controllers and put them into the MB-LON adapter. However, in the course of a detailed study of the documentation one thing became clear. In previous projects (Daikin and Buderus), all system components communicated with each other via their internal interface, and a separate gateway provided a connection between the internal interface and the external LON-network. Here, however, communication between the system components was provided by the same LON-network, so in the new project it was necessary not only to link the output variables with the MB-LON adapter, but also to repeat all existing connections between the system units, set by default factory settings. If this is not done, the cascade interaction between controllers will be destroyed when integrating the equipment. Considering this peculiarity of the system, the final project looks as follows: