Hello everyone,

I'm new to the DT800 world. I wanted to verify our DT800's operation, so I decided to follow Omega's short circuit test. I am using Analog Channel 1, 2, and 3 and I've shorted the inputs.

The negative terminals of the input are common to each other. I then loaded a program to take a reading for all three channels at a 500ms interval. I set the program to give me temperature and voltage reading.

I was mostly concerned with the voltage reading because I wanted to compare it with our thermocouple readings. The data that I got showed a voltage variation from +/- 3mV over a 3 minute interval using a short circuit test.

It seems that this will affect our recorded data when the thermocouples are inserted. Earlier, by probing the thermocouple terminal with a multimeter,

I only notice a 1mV change when I put the thermocouple in the freezer. Wouldn't this inherent noise voltage from the DT800 change the reading?

Thanks!

Good morning Qacer,

The short test is a good one to get the basic noise level of a system, I've repeated your testing on a DT800 here, I get a maximum of 5 micro volts of noise using your configuration. Note; I ran the test for 30 minutes and this figure includes drift as well as noise.

This would indicate the noise is probably coming from some other source.

1. How is the logger being powered?
2. What type of computer is attached? (Laptop, desk top)
3. Are you using fixed gains?
4. What is the result of the TEST command?

Cheers,
Roger

Hey Roger,

It was a mistake on my part when interpreting the voltage data. I found out that the voltage measurements returns the value in mV and not Volts.

Thanks!