Ventilation system...

[McKajVah]

Hi.

I'm trying to figure out how I can control my ventilation system using KNX.

Today the fans are controlled directly from the ventilation controller board via 0-10V signal.

What I want to do is using the Gira Homeserver and 0-10v input/output modules to manipulate this signal depending on whatever the situation is. Slow down extraction fan if kitchen hood or central vacuum is running, or increase extract fan if there is high humidity ++.

Also, I want to make sure the ventilation system keeps going if for some reason the Homeserver should fail...

My problem is I don't know how to make the system "default" back to directly input->output module when modules don't get a signal from the Homeserver, let's say, for the last 5 minutes.

-Kaj

[johnnychicago]

If the home server were to fail - wouldn't the ventilation go on with the last setting? Would that be a big problem?

Instead of going directly to the motors (thereby overriding freezing protection etc), have you thought about getting into the system? My Zehnder ventilation can be nicely talked to from the serial bus.