doc: Fixing typo for sensor psi calculation

[Phazz]

The psi sensors were not referencing the correct sensor for their calculation.

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[Phazz]

Thanks a lot for this beautiful project btw.

[JakobLichterfeld]

Thank you for your contribution!

@longzheng may I ask you for review, as it was latest edited in #4257 by you?

[longzheng]

This change looks good.

However this just reminded me perhaps using a template sensor to offer sensors in different units is not the best approach here. Perhaps we can use MQTT sensors with a value template to do the transformations. The benefits would be:

• remove sensor reference by entity ID
• reduce has_value logic in value template
• have device association

I'll open a separate PR for that change.

[JakobLichterfeld]

This change looks good.

Perfect, ty.

However this just reminded me perhaps using a template sensor to offer sensors in different units is not the best approach here. Perhaps we can use MQTT sensors with a value template to do the transformations. The benefits would be:

• remove sensor reference by entity ID
• reduce has_value logic in value template
• have device association

I'll open a separate PR for that change.

That sounds really like the best way forward, thanks in advance!