Reading a thermocoup​le with the SCXI 1520

Does the SCXI 1520 have something to account for the interface connection heat, and is it needed? I've heard this is what the thermocouple modules do, and it is necessary.

The SCXI-1520 uses the SCXI-1314 Module which does not have cold-junction(CJ)compensation capability - meaning it can not compensate for either the temperature of the connection to the DAQ system, nor, the additional voltage effect due to the dis-similar metal contacts of the DAQ system. This correction is absolutly necessary for accurate temperature measurement. I suggest you use a "third-party" cold junction module from a vendor such as OMEGA Engineering (www.omega.com). The CJ sensors are battery powered and reference the signal to 32 Deg F while at the same time providing standard copper leads for the DAQ system.

Similar Messages

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     Am Getting Inaccurate Readings When Some Channels of the SCXI-1520/SCXI-1314 Are Open Circuits
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    Surender Kumar

    No, DAQmx is superior and I strongly recommend you used DAQmx
    Elijah, I guess I understood the problem that Sunder is facing, coz even I had experienced it 2 years back
    What happens is if you scan only the channels to which sensors/strain gauges are connected, all is fine and you get good strain readings.
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    We use the SCXI-1520 signal conditioner to test and calibrate bridge sensors that we manufacture and it works great.  While the system is not used (i.e. when the operator connectes a sensor to the system) the SCXI-1520 is automatically isolated by using relays in a switching system.  The primary intent for this is to avoid possibly damaging the signal conditioner.  (Operators do regretful things.)   This means that the excitation power is floating with no load while the signal conditioner is disconnected,.  I was wondering if it would be appropriate to have the system automatically apply a load resistor to the excitation source to keep it "warmed up" so to speak.  Most sensors are a 350 ohm bridge and may be as high as 5000 ohms.  I was thinking of applying a common 330 ohm 1/2 watt resistor as a load.  (We are currently only using two channels at a time.)  Although I'm sure it would not make things worse, I just wonder if it's worth the bother.  Please advise...

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    Hi Frank -
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    You can find the user manual for anything at ni.com/manuals.  The manual for the SCXI-1520 is currently here.
    If you're programming in LabVIEW, you can find example programs for this device in the Example Finder.  (Click Help » Find Examples to open it.)  I recommending filtering by your hardware.  To do so, click the Hardware list in the bottom-left of the window and select "Add device".  After adding the SCXI-1520, select it from the list and check the Limit results to hardware box.  This will filter our examples down to the ones that work with your device.  They'll probably all be in the "Hardware Input and Output » Analog Measurements » Strain" folder.
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    LabVIEW 6.1
    SCXI-1000
    SCXI-1520
    SCXI-1314
    PCI-6031E
    Windows 2000
    Greetings-
    I'm trying to determine how the gain that is settable on a given channel of an SCXI-1520 module is combined with the gain that NI Max assigns to a Virtual Channel.
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