Vi for fast tc data acquisition

[Winzy68]

Hello,

Does someome have an example vi for fast data thermocouple acquisition using a ni9212 device?

[altenbach]

What is your definition of "fast"? How is this module connected to the rest of your system?

[Winzy68]

The ni 9212 module is inserted in a cDAQ 9171 SLOT which is usb  connected to the pc. For "fast", I mean a sampling rate of 50 points per second. The examples I've found in the labview libraries are not so fast.

[ZYOng · Accepted solution]

You need to set ADCTimingMode to High Speed. See Can I Sample at More Than 2 Hz With My NI 9212, 9213, 9214, and 9219?

[JÞB]

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@Winzy68 wrote:

The ni 9212 module is inserted in a cDAQ 9171 SLOT which is usb  connected to the pc. For "fast", I mean a sampling rate of 50 points per second. The examples I've found in the labview libraries are not so fast.

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Why?  There are VERY FEW cases that result in a delta temp measurable @50hz!  You really need to understand the theta jc (coefficient of thermal conductivity) of the unit under test.  If theta jc really is that high, it is likely that the mass of the thermocouple itself will swamp the system measurement because its mass will slow down any change in the UUT's temperature. 

You neither want nor need high speed tc measurements. 😀

[JÞB]

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@JÞB wrote:

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@Winzy68 wrote:

The ni 9212 module is inserted in a cDAQ 9171 SLOT which is usb  connected to the pc. For "fast", I mean a sampling rate of 50 points per second. The examples I've found in the labview libraries are not so fast.

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Why?  There are VERY FEW cases that result in a delta temp measurable @50hz!  You really need to understand the theta jc (coefficient of thermal conductivity) of the unit under test.  If theta jc really is that high, it is likely that the mass of the thermocouple itself will swamp the system measurement because its mass will slow down any change in the UUT's temperature. 

You neither want nor need high speed tc measurements. 😀

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The other case where the temperature rise is that fast would result from an explosion that probably obliterated the thermocouple.  In that case again, speeding up the measurement is not your biggest problem. 

[Winzy68]

Thank you very much! Now the system works properly!