OH3 - Modbus write float

Add-ons Bindings
,
1

Looking for some help on a problem I have come up with. I have MQTT sensors reading data into my OH3 server that I now want to send that data out via my Modbus configuration. To my HVAC controller. I am successfully reading Modbus data from the controller with no issues. So obviously my TCP slave and poller are set up correctly. I’ve configured my HVAC device to receive the temperature I’m trying to send it at 400007

my poller code

UID: modbus:poller:444bd70b8d
label: Poller HVAC
thingTypeUID: modbus:poller
configuration:
  start: 0
  length: 6
  refresh: 500
  maxTries: 3
  cacheMillis: 50
  type: holding
bridgeUID: modbus:tcp:e84dc005b3

my modbus data thing for taking MQTT to send out on modbus

UID: modbus:data:e84dc005b3:72d56673d1
label: Modbus Bedroom Temp
thingTypeUID: modbus:data
configuration:
  writeTransform: default
  writeType: holding
  updateUnchangedValuesEveryMillis: 1000
  writeValueType: float32_swap
  writeMultipleEvenWithSingleRegisterOrCoil: false
  writeMaxTries: 3
  writeStart: "6"
bridgeUID: modbus:poller:444bd70b8d

I’ve done both a Wireshark capture and looked at my event monitor. I don’t even see the point attempting to write I’m sure I am missing something on how to set this up.

2

What are you doing to make it write? Modbus writes are triggered by sending a command to a linked openHAB Item, there are no “auto-writes” or “reverse polling” features. Write on demand only.

Sounds like you want a rule that triggers from an incoming data
Item change, and re-writes the new data in a command to another Item.

There is a follow profile, which can be applied to an incoming channel to re-route data “as command” to some other channel, but users often get into knots trying to use this.

3

Thank you for your help. I am kind of lost on how you mean to create a rule on triggering from incoming data as I don’t see a way to do this. Though I was able to set the linked channel for my write to follow the profile and it seems to have done the trick. Thank you for your help!

4

Presumably there is an openHAB Item at the end of that.
You can create rules that trigger from various events.
One such event would be a change in a designated Item’s state.