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PaxInstruments / t100-electronics

A single thermocouple to USB adapter.
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Operating range #28

Open kehribar opened 9 years ago

kehribar commented 9 years ago

What is the desired operating range of the t100 dongle? I guess even the standard commercial range [0°C to 85°C] is high for our application.

This information will be used to calculate accuracy data of the measurement.

Most ICs give "maximum error over full temperature" information but they also provide "error vs. temperature" graph. If we can limit the operating range we can increase the accuracy of the measurements.

charlespax commented 9 years ago

The T100 should operate across the the full temperature range of J, K, R, S, T, N, E, and B thermocouple types.

For reference, here is the error chart of the NI USB-TC01 thermocouple to USB adapter. screen shot 2014-09-30 at 17 39 34

kehribar commented 9 years ago

Sorry If i couldn't expressed myself correctly :)

I meant the operating temperature of the actual dongle where the cold junction is. Since almost certainly a PC will involved and our dongle is plugged into it, operating range of the "dongle" will be limited I guess but what should be the range.

charlespax commented 9 years ago

Nope, that's my fault. What you said makes sense.

We can go with a smaller range than 0-85. Even the NI USB-TC01 has a smaller range. I don't think there is anything special about the NI USB-TC01; I just picked a more expensive device for reference. screen shot 2014-10-01 at 0 18 19 http://home.hit.no/~hansha/documents/lab/Lab%20Equipment/NI%20USB-TC01/resources/NI%20USB-TC01%20User%20Guide%20and%20Specifications.pdf

18 °C to 28 °C seem like a pretty reasonable range. As long as we document the accuracy int he final product we'll be good.

charlespax commented 9 years ago

For the next revision we should have a known operating range for the T100. If it is unacceptable, we should redesign as necessary.