PT104 Settings with UDP

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Bef
Newbie
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Joined: Thu Jan 10, 2019 7:46 am

PT104 Settings with UDP

Post by Bef » Thu Jan 10, 2019 7:59 am

Hello,
I'm using Ethernet UDP "raw" commands to set up a PT104 and to read data.

That works perfectly. (Lock device---read EEPROM-data---get measurement data---calculate resistance--- calculate temperature)
Now I'm wondering how to set up different PT100 wire configurations.
In the PICO-Software there are options for 2-wire, 3-wire, 4-wire, etc.
In the programmer's guide I only see 5 commands (0x30 - 0x34). The only configuration I see is the activation and the gain setting for each channel.

Are there any more commands? Or do I have to set up the PT104 via USB?

Thank you for your help!

Martyn
Site Admin
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Location: St. Neots

Re: PT104 Settings with UDP

Post by Martyn » Fri Jan 11, 2019 7:54 am

The number of wires does not change what happens in the device, it just changes the way you use the readings that are returned. This calculation is handled in the driver

For 2 and 4 wire
result = (channel calibration * (measurement 3 - measurement 2))/(measurement 1 - measurement 0)

For 3 wire
result = (channel calibration * ((measurement 3 - ( measurement 2 - measurement 1)) - measurement 2))/(measurement 1 - measurement 0)
Martyn
Technical Support Manager

mimateo
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Joined: Thu Jan 02, 2020 6:17 pm

Re: PT104 Settings with UDP

Post by mimateo » Thu Jan 02, 2020 6:44 pm

I have a similar problem.
I can read the EEPROM and get the Ch1 Calibration and use it as an int32_t: 0x6e754a30 --> 1853180464
Then I read channel 1 via raw Ethernet protocol and I get the following values:
0 : 0x20002771 : 536881009
1 : 0x20284D9F : 539512223
2 : 0x20287EDA : 539524826
3 : 0x205438BD : 542390461
After using the documentation formula for 4 wire and divide by 1000.
I've got a value that seems to be not valid (temperature is around 22º C):
2019.9929644052759
What am I doing wrong?

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