# Communicate over modbus with Hörmann garage door

**URL:** https://discourse.nodered.org/t/communicate-over-modbus-with-hormann-garage-door/85565
**Category:** General
**Tags:** modbus
**Created:** [15 February 2024 14:39 UTC](https://discourse.nodered.org/t/communicate-over-modbus-with-hormann-garage-door/85565 "2024-02-15T14:39:58Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [15 February 2024 19:49 UTC](https://discourse.nodered.org/t/communicate-over-modbus-with-hormann-garage-door/85565/2 "2024-02-15T19:49:20Z")

</div>

> [@RobinR1](#):
>
> However, I seem to need Function Code 17, which seems not implemented in node-red-contrib-modbus or any other modbus implementations I find in the Node-RED library.

I dont think FC 17 is implemented in the underlying Modbus library ([jsmodbus](https://www.npmjs.com/package/jsmodbus)) - well it isnt stated as NOT being supported but there is [this issue](https://github.com/Cloud-Automation/node-modbus/issues/242) that speaks of adding FC 17 (the item remains unchecked)

So, your options are:

1. Raise a "Feature Request" on the github repos + cross your finger 🤞
2. Create Pull Requests to both jsmodbus and node-red-contrib-modbus to add FC 17 support
3. Fork both jsmodbus and node-red-contrib-modbus to add FC 17 support and start using it / publish own package.
4. DIY the protocol in Node-RED.

DIY\* It is not that complicated. The CRC calcs are well documented (there are even examples on this forum)

If you want a starting point, I wrote [a simple demo](https://discourse.nodered.org/t/how-to-create-an-modbus-tcp-alarm-status-dashboard/43041/14) you could build upon.

To aid you in this, there is an online modbus decoder. Here it is decoding the data in the github repo you linked:

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/8/7/87991549df78e402b41a43b781aec7758432cf6e.png)

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