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Combining Cascade OT with Theben KNX Heating controller

Posted: Mon Oct 10, 2016 10:21 pm
by LauPro
Currently I have to operate a building where we want to use the Theben KNX modules for heating control. There will be around 20-30 rooms in the building which will have their own heating control. In the documentation from Theben I see the Theben OT-KNX unit can support up to 20 rooms. This unit has an Open Term output.

But on the other hand I want to use the existing two gas burners (OT or 0...10V supported) in cascade mode to heat the building.

I think the best way to control the system is to use a Siemens RMK770 (https://www.downloads.siemens.com/downl ... &id1=30411) to control the gas heaters in cascade control (and the pumps / valves required for this).

But how can I connect the KNX actuators and thermostats with this RMK770 controller? I will have more than 20 zones, so one Theben OT-KNX will not be enough but how can I combine multiple?

What is the best way to go?