Wrong decoding of negative setback values in Climate Control Schedule CC

[AlCalzone]

Discussed in #7362

^{Originally posted by @bueeler November 5, 2024}

Checklist

• I have read and followed the above instructions

• I have checked the troubleshooting section and my problem is not described there.

• I have read the changelog and my problem was not mentioned there or the fix did not work.

Describe the issue

I am using MT02650 TRV and use "Climate Control Schedule CC" command class to adjust the TRV set point based on input from room thermostat.
After sending negative setback values through function setOverride() from "Climate Control Schedule CC" command class, the value for "Override state" is not correctly shown in Z-Wave JS UI:

I would expect that negative setback values are correctly displayed as negative number in Z-Wave JS UI (as it is done for positive values). e.g. value "252" from screenshot above shall be displayed as "-0.4".

Issue seems caused by missing handling for negative numbers in function decodeSetbackState():
https://github.com/zwave-js/node-zwave-js/blob/master/packages/cc/src/lib/serializers.ts#L31
The specification defines the value as signed byte:

but the implementation treats it as "number".
All negative values where val>=128 (0x80) are handled as "special state", instead handled as negative setback state.

Software versions

zwave-js-ui: 9.25.0.38e48a8
zwave-js: 13.10.1

Z-Wave Controller (Stick/Dongle/...)

It should be unrelated to controller

Device information

Manufacturer: Devolo
Model name: ...
Node ID: e.g. 008, 005 ...

Checklist

• I made sure to provide a driver log on level debug.

• The log includes a re-interview of the problematic device (if applicable).

• The log includes the problematic interaction with the device (if applicable).

• I provided the node ID of the problematic device (if applicable).

Upload Logfile

zwave-js-ui-store.zip