SuperUser
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Tweak the RTD output

Can we tweak the RTD output in MFI?

I have one I set up and it reads 5.31 where it should be down around 2.0C.
Walks in, tells it like it is, walks out , milks a cow
SuperUser
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Custom RTD sensor maybe

How do I create a custom RTD sensor so I can fine tune the conversion, so the reading is correct.
Walks in, tells it like it is, walks out , milks a cow
New Member
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Registered: ‎09-10-2012

Re: Tweak the RTD output

RTD are standard, meaning you have 100 ohm at o.o Celsius, and increasing one Celsius degree each per 0.385 ohm resistance (10 C will be 103.85 ohms), if you cannot get does reading ok RTD is faulty, however I think you can create customized device at "custom.json" and adjust the conversion variable, in order to do a sort of calibration.....
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Re: Tweak the RTD output

Could the issue potentially be that you've put it on too long of a wire lead?
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Re: Tweak the RTD output

It's on about 12 feet of stranded 16 gauge wire. Outdoor rated with 3 leads and a bare common lead.
The Probe i have is a platinum RTD probe.
I want to create a custom device.
Does anyone know how ?
I can't find any info in the wiki for a custom RTD device.
Walks in, tells it like it is, walks out , milks a cow
SuperUser
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Re: Tweak the RTD output

It's on about 12 feet of stranded 16 gauge wire. Outdoor rated with 3 leads and a bare common lead.
The Probe i have is a platinum RTD probe.

I want to create a custom device.
Does anyone know how ?
I can't find any info in the wiki for a custom RTD device.


I hate to do this but here goes

BUMP!
Walks in, tells it like it is, walks out , milks a cow
Previous Employee
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Re: Tweak the RTD output

RTD has no conversion factor. Like user antofaun suggested, it's a standard.
Please verify sensor and mPort separately to see which device is in error.
Is your error a constant == 3.31? Or does the error change at say 40 deg C?
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Re: Tweak the RTD output

During the wash (every 2 days) the normal High temp is between 56 and 58 C , the sensor reported a spike of 62.C
Tomorrow it will wash again. I'll keep an eye on it.
I might order one of these (PDF file)
www.watlowdistributor.com/HTML/Watlow-RTD-RB-spec.pdf
Also do you think the wire I used might have caused the extra resistance?
Would I be better off with a 12' run of tough cable?
I mounted the mport in an enclosure to keep the humidity away as close as I dare to the tank.
Walks in, tells it like it is, walks out , milks a cow
SuperUser
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Re: Tweak the RTD output

I just pulled out my RTD probe and sunk it in a glass of water partly frozen with extrfa ice cubes.
It's holding steady at 1.45C. It dropped to that level and has held for almost 10 minutes now.
Walks in, tells it like it is, walks out , milks a cow