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How Can I Use the CJC on the SCC-68 to Read the Ambient Room Temperature

Primary Software: Utility Software>>Measurement & Automation Explorer
Primary Software Version: N/A
Primary Software Fixed Version: N/A
Secondary Software: N/A
Hardware: SCC>>Carriers

Problem:
I would like to use the CJC sensor to read the ambient temperature of the room.  How can I access and scale this signal?

Solution:
The CJC can be accessed from pin 70 and 71 in the SCC-68.  You will need to wire those pins to one of the differential inputs to read the voltages off of the CJC.  The closest channel is AI7 which are pins 57 and 23, so you will need to physically wire pin 70 to 57 and pin 71 to 23.  Once you have that connected, you will have to setup the scale for the sensor.


To scale the CJC value to a temperature value, you will need to apply this equation:


To apply this equation:

1. Save either the CJC Celsius Scale.txt or CJC Fahrenheit Scale.txt file that is attached to this KB to your computer
   
2. Open the Measurement and Automation Explorer
3. Right click Scales
4. Click Create New...
5. Select NI-DAQmx Scale
6. Click Next
7. Select Table
8. Type in "CJC Scale" for the name, or whatever name you choose to give it
9. Click Finish
10. Click Import
11. Browse to the scale table that you saved
12. Select Comma for the Delimiter
13. Click Ok
14. Select Volts for the Pre-Scaled Units
15. Click Save

If you chose the Fahrenheit scale then you should end up with something like this:


You can now apply this scale when you create a task.

Related Links:
SCC-68 User Guide and Specifications

Attachments:

SCC-68_temperature_CJC.vi
CJC Fahrenheit Scale.txt
CJC Celsius Scale.xls
CJC Fahrenheit Scale.xls




Report Date: 08/01/2007
Last Updated: 06/02/2009
Document ID: 4C0ABG9S

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