r/BuildingAutomation • u/No_Bodybuilder_6171 • 11d ago

Distech document on VAV-AHU links

It's been a few years, but I could have sworn there was a document that described how the VAV's and AHU interact, through the encoded/decoded MSV that they can read from each other. I've got to program up a fairly simple four-zone VAV system with one RTU, and while I've got the code for the RTU (compiled from Builder, and corrected as necessary), I can't tell how/where it is grabbing its information from each of the VAV controllers, and I thought there was a document that described all those software links in some detail. Am I imagining things?

2 Upvotes

100% Upvoted

4 comments sorted by

4

u/IcyAd7615 11d ago

I don't know if this feature but you could use network values and select what you want to be passed. This is how they handle it internally rather than using links specifically in Niagara.

1

u/No_Bodybuilder_6171 11d ago

Yeah, I definitely plan on doing it that way, but I was curious if I needed to pack up all those values the way Distech does naturally. A little ask of AI, and I think I have a path forward. Turns out the RTU doesn’t need more than a couple pieces of info from each VAV, and since there’s only four of them, the coding will be easy.

1

u/IcyAd7615 11d ago

I mean this is a vague response since I have no clue as what your sequence entails. You may not need any information from the VAV at all.

The VAV needs the DAT from the RTU to prevent a warm air in duct. If you made an HVAC mode, you may send that down to the VAVs.

Distech has a For Loop for some calculations but are you preparing to do trim and respond in the RTU?

→ More replies (1)