Configuring & Reading a Thermocouple | LabJack
 
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Configuring & Reading a Thermocouple

T-series devices have various configurable features as part of the Analog Input Extended Feature (AIN-EF) system. The following example demonstrates how to configure and read a thermocouple input in the Kipling Register Matrix.
 

1. First connect the thermocouple between AIN0 and GND. In Kipling, navigate to the Register Matrix page and type ain0 in the search bar.

 

2. Add the following registers to the active register list:

  • AIN0_EF_INDEX
  • AIN0_EF_CONFIG_A
  • AIN0_EF_READ_A

These are the AIN-EF registers for configuring thermocouple measurement.

Kipling has special high-level support for AIN-EF configuration on the Analog Inputs tab for the T7, but for the purpose of this tutorial we are using the Register Matrix instead.

 

3. Configure the thermocouple input by writing the following values to each of the pinned registers.

Write 21 to INDEX to set AIN0 to use the AIN-EF for Thermocouple type J:
AIN0_EF_INDEX = 21

We write a 1 to CONFIG_A so that the output is in deg C:
AIN_EF_CONFIG_A = 1

 

4. The AIN0_EF_READ_A register should be outputting the scaled temperature value in degC.
 

 

5.  To save the configuration so the AIN-EF thermocouple feature will be configured at device boot-up, go to the Power-Up Defaults tab and click "Configure Power-up Defaults". Make sure that "Current Device Settings" option is selected.

This step is recommended for LJLogM, LJStreamM, and other simple polling programs because they don't configure AIN-EF. If you're writing your own software, however, you can configure AIN-EF programmatically.

 

 

Reading a Thermocouple Input in LJLogM

Once the AIN extended feature is configured (above), you can read AIN0_EF_READ_A using any row in LJLogM.

Close the connection in Kipling before opening LJLogM. A LabJack can only be opened via USB by one software process.

 

Reading a Thermocouple Input in LJStreamM

AIN Extended Features are not supported in Stream mode. LJStreamM cannot read thermocouple inputs while streaming.

 

Reading a Thermocouple in DAQFactory

To configure a thermocouple input you can use steps 1-5 above or write AIN0_EF_INDEX = 21 (for Type-J) and AIN0_EF_CONFIG_A = 1 (for deg C) in DAQFactory. See "Device Configuration" on the DAQFactory for LJM page.
To read the temperature look in the AIN0_EF_READ_A register. See "Linking LabJack Inputs/Outputs to DAQFactory Channels" on the DAQFactory for LJM page.

 

Reading a Thermocouple in Your Program

Use steps 1-5 above to configure, or write the desired configuration registers at the start of your program with a couple calls to eWriteName or a single call to eWriteNames.

To get a temperature reading read the register AIN0_EF_READ_A with a call to eReadName.

Or, in the applicable archive, look for an example called "Write Read Loop with Config" that can be used to both configure and read the timer.