Bridge/Thing Structure

(Garry Mitchell) #1

Hi there,

I’m wondering if this is a valid structure for a Binding I’m looking to write for the ClearOne XAP800/XAP400 audio matrix devices:

  • Bridge
    • Thing
      • Thing
      • Thing
    • Thing
      • Thing
      • Thing

The top-level Bridge will be a Serial connection to a stack of devices which are then inter-linked. Each first level Thing will have some Channels & Properties itself which relate to the individual device, and it has 8-12 Outputs, I’d like each one of these to be a Thing with individual channels for source, volume, mute etc.

I’ve got as far as defining the top level Bridge, which is then Discovering each top-level Thing, and I’ve added an supported-bridge-type-refs entry to the bottom-level Thing, which does allow me to select the first-level Thing, but I’m getting a “Bridge Uninitialized” error (but the Thing is relates to is online)

If this structure isn’t possible, then I’ll just go for a flatter design with the Unit and Outputs at the same level, just referencing the main Bridge (which is where all communications will need to be passed through anyway)

Thanks in advance for any advice.


(David Graeff) #2

What you would normally do is Bridge->Bridge->Thing.

But how about eliminating the first bridge (serial connection) and pull that configuration into the first Thing (which becomes a Bridge).

Internally you can still pool your serial connections, and reference count them etc.

(Rossko57) #3

You may wish to look at Modbus binding. That has structure

Bridge    // this defines a physical box and pathway
    Bridge //  this defines a group of registers and how to access them
        data Thing // describes a register and how to interpret it
        data Thing
    Bridge // some other group (usually) on the same box
        data Thing

Modbus is very simplistic, which at the same time allows enormous flexibility. Manufacturers all exploit this in different ways, while there is no method of self-discovery at all.
The upshot is that Modbus is a nightmare of detailed manual configuration.

The structure is rather clumsy really, but the only realistic way to allow for the flexibility. For example, the top level Bridge could be a gateway device leading to several other differing Modbus devices. The three-level structure accommodates that without further expansion, a two-level structure would have much duplication.

That’s not a recommendation to do it that way, just to illustrate that it works. As you have some discovery, choices might well be different.

Gut says a stack of devices should be represented as a Thing for stack/pathway and a Thing for each device.:smiley: but I suppose it depends how intimately they are connected.

(Garry Mitchell) #4

Thanks guys, I’ve tweaked to Bridge -> Bridge -> Thing, and I’ve got a hierarchy of “ONLINE” things now showing in PaperUI.

I’ll certainly have a look at Modbus for some inspiration of dealing with a multi-level Bridge setup.