Reply To: Meter Hydros 21 address

Matt, my understanding is that the warning to not use address “0” came from a Meter/Decagon integration manual and from real-world experience. If I’m not mistaken, some sensor manufacturers reserve the “0” address for all sensors to use all the time, even when their address has been changed. This allows for a back-door to poll a line for all the connected sensors to find out the status of what’s connected. When manufacturers do this, they often disable sending data from that address. This is also the case for some Modbus implementations.

I think Meter has implemented this convention for some but not all of their sensors. I can’t remember which. Also, since Meter has purchased Decagon, we’ve seen them slowly modify their SDI-12 protocols with firmware updates, sometimes silently.

Sara & Shannon can likely provide more detail. Alternately, you could call Decagon/Meter. They are a small company and would likely connect you to an engineer relatively quickly.