background image

If you are unsure which thermocouple lead is positive and which is negative, refer to the
thermocouple documentation or the thermocouple wire spool.

Figure 5.

 Connecting a Thermocouple Input Signal to the NI USB-TC01

Thermocouple

TC–

TC+

USB-TC01

For best results, NI recommends using insulated or ungrounded thermocouples when possible.
If you need to increase the length of your thermocouple, use the same type of thermocouple
wires to minimize the error introduced by thermal EMFs.

Temperature measurement errors depend in part on the thermocouple type, the temperature
being measured, the accuracy of the thermocouple, and the cold-junction temperature. Error
graphs for each thermocouple type connected to the NI USB-TC01 are provided in the

NI USB-TC01 Device Specifications

 document, available at 

ni.com/manuals

.

NI USB-TC01 Circuitry

The NI USB-TC01 device’s thermocouple channel passes through a differential filter and is
sampled by a 20-bit analog-to-digital converter (ADC), as shown in the following figure.

Figure 6.

 NI USB-TC01 Input Circuitry

3.3 V

10 M

Isolated

GND

TC

Low pass filter

and

protection

Isolated

ADC

TC+

TC−

10 M

Thermocouple Measurement Accuracy

Temperature measurement errors depend in part on the thermocouple type, the temperature
being measured, the accuracy of the thermocouple, and the cold-junction temperature sensing
accuracy.

6

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ni.com

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NI USB-TC01 User Guide

Summary of Contents for USB-TC01

Page 1: ...ruments USB TC01 Manual Get Pricing Availability at ApexWaves com Call Today 1 800 915 6216 Email sales apexwaves com https www apexwaves com modular systems national instruments temperature input dev...

Page 2: ...ribes how to use the device For specifications refer to the NI USB TC01 Device Specifications document available at ni com manuals Figure 1 NI USB TC01 Device Safety Guidelines The following section c...

Page 3: ...ution occurs or dry nonconductive pollution occurs that becomes conductive due to condensation You must insulate signal connections for the maximum voltage for which the device is rated Do not exceed...

Page 4: ...boxes switches socket outlets in the fixed installation and stationary motors with permanent connections to fixed installations Measurement Category IV is for measurements performed at the primary el...

Page 5: ...ot start you can manually run the software by locating the NI USB TC01 under My Computer and double clicking TC01Launcher exe Figure 3 NI USB TC01 Launch Screen Through the NI USB TC01 launch screen y...

Page 6: ...measurements with the NI USB TC01 launch screen you can also build custom software for your NI USB TC01 with LabVIEW and NI DAQmx driver software LabVIEW uses graphical icons and wires that resemble a...

Page 7: ...racy of the thermocouple and the cold junction temperature Error graphs for each thermocouple type connected to the NI USB TC01 are provided in the NI USB TC01 Device Specifications document available...

Page 8: ...mocouple connector type and thermocouple type should match Open Thermocouple Detection OTD The NI USB TC01 is equipped with open thermocouple detection With OTD any open circuit condition at the therm...

Page 9: ...the cold junction compensation CJC sensor used to measure the cold junction Minimizing Thermal Gradients Thermocouple wire can be a significant source of thermal gradients if it conducts heat or cold...

Page 10: ...ister to register your National Instruments product Product registration facilitates technical support and ensures that you receive important information updates from NI A Declaration of Conformity Do...

Page 11: ...and third party legal notices in the readme file for your NI product Refer to the Export Compliance Information at ni com legal export compliance for the National Instruments global trade compliance p...

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