Operating range

[kehribar]

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]

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.

[kehribar]

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]

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.

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]

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