COP sensor keeps logging repeated values even when the plugin does not call Update()

[Ragdag]

Hi all,

I’m developing a Python plugin for a Luxtronik heat pump controller and I’ve run into an odd behavior with Custom Sensor devices (Type=243, SubType=31).

What I’m doing

• I calculate COP (Coefficient of Performance) only when the compressor is actually running.
• When COP is not meaningful (cooling/no requirement/standby), the plugin intentionally does not call Update() for the COP devices.
• The plugin logs “Skipping update … (no valid value)” in those cases.

The problem
Even though the plugin is not calling Update(), Domoticz still shows repeated identical COP values at 5-minute intervals in the graph export. Example:

Code: Select all

"2025-10-19 13:00:00";3,15
"2025-10-19 13:05:00";3,15
"2025-10-19 13:10:00";3,15
"2025-10-19 13:15:00";3,15
"2025-10-19 13:20:00";3,15
"2025-10-19 13:25:00";3,15
"2025-10-19 13:30:00";3,15

During that same period, the plugin logs clearly show no Update() calls for COP:

Code: Select all

2025-10-19 13:30:12.103 Status: WP: [DEVICE] Skipping update for COP total (no valid value).
2025-10-19 13:30:12.124 Status: WP: [DEVICE] Skipping update for COP heating (no valid value).
2025-10-19 13:30:12.125 Status: WP: [DEVICE] Skipping update for COP DHW (no valid value).
...

Sometimes Domoticz does produce a proper gap (no points) during long idle periods, so it’s not 100% consistent. Example of a gap between:

Code: Select all

2025-10-19 00:35:00  ->  2025-10-19 08:40:00

The last seen time does reflect the proper last data point.

What I would expect
If Update() is not called, no new datapoint should be stored. I’m trying to avoid flat “carry-forward” tails for COP because they skew daily/monthly averages.



Questions

• Does Domoticz internally “carry forward” the last known value for Custom Sensor devices into 5-minute buckets even if Update() was not called?
• If so, is there any setting or device flag to disable that behavior per device?
• Is there a recommended device type or Update() pattern for metrics like COP where “no datapoint” is preferred during idle periods?

Implementation notes (in case helpful)

• COP devices are Custom Sensor (Type=243, SubType=31).
• When COP is N/A I return None from the converter and the plugin never calls Update() for those units.
• I also mark COP devices as non-graphing in my own tracker logic to avoid periodic forced updates.
• I gate COP on:
  • Mode (heating/DHW only),
  • Passive cooling flag,
  • Compressor frequency > 1 Hz,
  • Power > 50 W and Heat Output > 100 W (to ignore standby/noise).

Any guidance on whether Domoticz is expected to backfill/carry-forward values in graphs when no Update() occurs, and how to opt out of it, would be greatly appreciated. If there’s a better device type or approach for COP, I’m happy to adjust the plugin.

[gizmocuz]

That's correct, Domoticz keeps using the last value
You can prevent this by going to Settings->Log History and enabling 'Only add newly received values to the Log'

[Ragdag]

That's correct, Domoticz keeps using the last value
You can prevent this by going to Settings->Log History and enabling 'Only add newly received values to the Log'

Awesome, thanks will try that.
There is no way to do that at a per device level?

Does not fully explain why it still did a gap in my current setup.

[Ragdag]

@Gizmocus, will that setting then also effect the calculation and reports?

[Ragdag]

That's correct, Domoticz keeps using the last value
You can prevent this by going to Settings->Log History and enabling 'Only add newly received values to the Log'

So far it works indeed. It would be really great if this was a per device option instead of system-wide.