TC-08 USB with odd behaviour

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Joined: Tue Jan 15, 2013 2:27 pm

TC-08 USB with odd behaviour

Post by dutch_dk »

Hi there.

In 2013 I opened this topic: search.php?author_id=22515&sr=posts

In short the TC-08/USB monitors the temperatures of a heat pump.
The heart of the pump is a compressor, controlled by a frequency converter (FC).

The readings from my TC-08/USB suddenly drops as if as the polarity on the probes switches?
To day.jpg
The problem described in 2013 still persists, but I have learned to live with it.
(The power to the computer is drawn from the same supply as the heatpump)
During the years I have finished grounding of all parts, soldered a wire to the PCB in the TC-08, and made a wired connection to the chassis of the computer, and all are connetcted to the chassis of the heatpump.
All the probes is now covered with heat crimping flex, to avoid mecanical contact with the unit.

My first thought was that the FC made some electrical noice, but the problem occures also in the summer, where the compressor is not active.
Then I wondered if it was caused by electrical noise from some other unit in the house, but I have not been able to trace any simultaneity to other utility items starting or stopping.

See attachments.
One showing today's curve.
To day.jpg
One showing a normal summers day,
One showing a normal summers day with the problem.
Summer 2.jpg
Any clou what I could to look for ?
Any ideas ??

Thank you all in advance ......


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