Maximum sampling rate for thermocouple measurement with BNC2120

[vivegananth]

Hi,

I'm using NI-PCI-MIO-16E-1 with BNC-2120 interface to measure temperature using K-type thermocouple which is capable of  measuring at 4khz sampling rate. But, If I increase the sampling rate in the NI-Labview program, temperature value also incresing even at the same ambient conditions. your suggestion on this, will be highly appreciated

what is the maximum sampling rate possible in NI-PCI-MIO-16E-1 DAQ kit for measuring temperature with K-type thermocouple.

[Henrik_Volkers]

If you multiplex analog signals, there is the effect of ghosting due to the settle time of the sample and hold capacitor.

So if you read multiple channels, you will see that effect. Since TC voltages are quite small this effect can result in big errors.

I don't konw your DAQ setup, but if are able to read only this one channel you shouldn't see that problem.

(Maybe the DAQ will read more channels in your setup even if you are only interested only in one)

This DAQ&BNC box looks like a swiss army knive, but as you migth know even McGyver would prefer the rigth tool.

The best solution for fast and low uncertainty measurements are individual sampling units.

The spec usually mention the settle time error for different source impedances. TCs, especially the small fast ones, easely get up to some 100 Ohms. (TC resistance measurements need a AC exitation, or do it twice with swapped connections)