Feed KNX sensor data into VTH1660CH for alarm functionality

eagle_eye

Young grasshopper
Jul 4, 2018
31
3
Germany
Hi,
a while ago I started to use my VTH1660CH / VTO2000A as a alarm system. For this I need to provide the available sensor data of my KNX system to the VTH1660CH and/or VTO2000A. Because
- both system shall be galvanic separated (failure in one system shall not damage the other, grounding not the same, ...),
- the interface part shall consume no / very less power and
- the mean-time-between-failure (MTBF) shall be as high as possible (>10 years)
it was not easy to find a simple and cheap solution.
After some trials with COTS opto copplers, only the darlington opto copplers were able to be used for:
- interface between KNX and VTH and
- adding a buzzler for acustical feedback from the KNX system

My solution is attached (cuircuit drawing and layout).

1577621932802.png


Remarks:
- darlington opto copplers might be ESD sensitive => be carefull during testing / installation
- bigger BPT-24BX (piezo buzzler) must be placed far way from the ICs, otherwise EMC might trigger the buzzler(s).

Do you have any remarks? Any better sollutions?
I installed them yesterday. Up to now it is working without any problems.
 

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