This package provides nodes for the node-red project to interact with the Systemair SAVE air handling units.

Currently communication over Modbus TCP over the SystemAIR IAM module or another Modbus gateway is supported. You may be tempted to rely on the popular node-red-contrib-modbus package to communicate with your air handing unit, but I found it to have trouble doing so reliably due to the specifics of how SystemAIR devices implement the Modbus protocol. In particular, these units frequently return a status code indicating that the request should be retried. Most plain Modbus libraries will treat this code as a failure, where the right thing for SystemAIR devices is to retry the request a moment later. Nodes provided in this library handle this and similar other specifics for you.

The systemair register node configuration provides a list of registers you can choose to operate on with a convenient selector. All of the known and documented registers are available for selection here, saving you the effort in correlating with the register lists.

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For the simplest automations this may be sufficient. As the automations get more complicated, users may discover some of the functionality or information in the SystemAIR device to be exposed through an inconveniently large number of distinct registers. This library makes it straightforward to interact with this data through a concept of "virtual registers". These registers expose a concept, such as the alarm state, as a single node that apply special logic to a register operation. For the virtual alarm register in particular this node will read out all of the registers indicating alarm states and present them as a single key-value record to inspect.

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All in all, this package provides quite a convenient way to integrate your SystemAIR air handling unit with your home automation needs. For example here's a part of my flow, with all sorts of interesting data being saved to InfluxDB for later viewing and graphing. This flow also implements some automations such as requesting a refresh mode after a shower is taken, or a cooker hood mode when the cooker hood is turned on.

Contribution guidelines

I consider this project largely complete for my own needs. I anticipate it to be updated occasionally in case of an incompatibility with new versions of node-red or node; or if I end up discovering new requirements. For anything else, please implement the desired changes yourself and submit a PR. Thank you!

Disclaimers

This is a third-party project. Systemair, SAVE, the Systemair logo and various other similar identifiers or assets that are referenced in this project are (most likely) trademarks and otherwise registered marks of Systemair AB or a related legal entity. Use of these names is only meant to refer to the vendor’s products and in no way implies an endorsement or any other relationship between the vendor and this project.