Why does Type K TC jump around /- 2 degrees w CJC on

[MPH]

I am trying to read a type K TC with a SCB68 terminal board and a 6062E DAQ card. I have enabled CJC compensation on channel 0. The TC on channel 1 is fluctuating +/- 2 to 3 degrees. How can I eliminate this??

[Mohan Pawar]

"MPH" wrote in message
news:50650000000800000037C20000-1077587809000@exchange.ni.com...
> I am trying to read a type K TC with a SCB68 terminal board and a
> 6062E DAQ card. I have enabled CJC compensation on channel 0. The TC
> on channel 1 is fluctuating +/- 2 to 3 degrees. How can I eliminate
> this??

Two possibilites:
1) To _see_ stable data average the readings before displaying. If
acquisition rate is 40 points/s, display an average of 20 points every half
second. Rarely does one need temperature measurement at a rate high enough
to justify high speed daq hardware. Thermal properties of most objects
yield only a slow temperature change (as compared to available daq rates on
most plug-in cards.)

2) Differential mode has significantly low
fluctuations. How is your board
configured for analog inputs - single ended or differential?

*************
Mohan Pawar

[MPH]

Mohan,

Thanks for the quick response.

The 6062E DAQ card is configured for differential input. I don't really want to compensate for the instability of the SCB68 by averaging over time. I am going to average the data, I just don't want to do it when it is swinging so wildly.

Is this the best stability I can hope for with the 6062E/SCB68 combination?