Thermocouples, the SCB-68, and NI-DAQ Virtual Channels/NI-DAQmx Tasks
Hardware: Counter/Timers (TIO)>>Connectivity>>SCB-68, Multifunction DAQ (MIO)>>Connector Blocks>>SCB-68
Problem: I want to take advantage of the IC Sensor of the SCB-68 to do cold junction compensation (CJC). I also want to use the NI-DAQ virtual channels and NI-DAQmx Tasks. Can I use the CJC with either one?
Solution: Depending on which version of NI-DAQ you are using, this operation will vary. If you are using Traditional NI-DAQ or NI-DAQ versions 6.5.1 to 6.9.3, follow the first set of instructions. If you are using NI-DAQmx, follow the second set of instructions.
Traditional NI-DAQ or NI-DAQ versions 6.5.1 to 6.9.3
- In the Measurement & Automation Explorer (MAX), under My System, navigate to Devices and Interfaces»Traditional NI-DAQ (Legacy) Devices.
- Right-click your device and select Properties. Go to the Accessories tab and choose SCB-68. Check the CJC Jumper Set box. This will make channel 0 the CJC built-in tool.
- Expand Data Neighborhood and right-click Traditional NI-DAQ Virtual Channels. Select Add Channel.
- Configure your thermocouple channels (you do not have to configure the CJC channel). Set the virtual channel for Analog Input, name the channel, choose the proper thermocouple type, and choose your temperature scale. Be sure to choose the correct channel on your device.
- Choose Built-In as the CJC source. You will be able to read temperature from the thermocouple on any channel besides channel 0. It will be dedicated to the CJC sensor on the SCB-68.
NI-DAQmx
- In the Measurement & Automation Explorer (MAX), under My System, navigate to Devices and Interfaces»NI-DAQmx Devices.
- Right-click your device and select Properties. Go to the Accessories tab and choose SCB-68.
- Click Configure and check the Temperature Reference Enabled box. Click OK. Click OK.
- Expand Data Neighborhood and right-click NI-DAQmx Tasks. Choose Create New and select NI-DAQmx Task.
- Configure your channel by selecting Analog Input, then selecting Temperature and Thermocouple.
- Choose the analog input channel that you wish to measure, name your channel, and click Finish.
- In the DAQ Assistant, set your thermocouple type and select Built In as the CJC source. Adjust the Input Range, Task Timing, and Task Triggering if you need to.
- Click Test to verify that the task works properly.
Related Links: KnowledgeBase 2MO86AMQ: How Can I Read the Value of the Cold Junction Compensation of the SCB-68 (SCB-100)? KnowledgeBase 25LJ14YF: How to Create a CJC Virtual Channel for Use with Thermocouple Virtual Channels KnowledgeBase 20D9DHHE: How Do I Configure the Switches for CJC Sensor on the SCB-68?
Attachments:
Report Date: 09/29/1997
Last Updated: 01/30/2009
Document ID: 11SCAVHL
