Labview and InstaCal Showing Different Values

[Mackenzie Cox]

I have Labview set up to read thermocouple readings from my USB 2416. For some reason, all of the thermocouple channels are giving consistent and accurate measurements in instacal, but when I boot up labview (after closing out instacal), some of my thermocouples are giving extremely inconsistent readings. It is not my block diagram, as I have tried different thermocouples in the same channel I am trying to read and they work fine. I also know it is not my thermocouple because they are working fine when I read them in instacal. Any insight as to what is going on?

[Fausto]

Hello @Mackenzie Cox.

Please close LabVIEW and open InstaCal.  Reply with a screen capture of the USB-2416 channel configurations.  Do you have the data rate set to 60 Hz for each thermocouple channel?  

As stated on page 16 of the USB-2416 user's guide, "thermocouples can pick up noise in your environment, select a data rate based on the primary noise 
frequency. For example, to reduce the effect of 60 Hz noise, select a data rate of 60 (or a sub-multiple of 60, such as 10 or 20)".

https://www.mccdaq.com/pdfs/manuals/USB-2416.pdf

Please test the VI examples attached to the following MCC Knowledgebase articles.

https://kb.mccdaq.com/KnowledgebaseArticle50481.aspx

https://kb.mccdaq.com/KnowledgebaseArticle50396.aspx

Regards,

Fausto

 

[Mackenzie Cox]

 

Here is my board configuration. I have all of my thermocouples set to 60Hz for the data rate. But, all of the thermocouples read fine in Instacal, it is just specific ones that are having issues in labview.

 

I tried out those configurations you attached, same issue.

[Mackenzie Cox]

I also have two pressure sensors connected that require a power supply. From troubleshooting, I realized that when the power supply is disconnected, labview is able to read the thermocouple sensors fine. The issue here is obviously I need the thermocouples and pressure sensors to be able to be read at the same time. Does this provide any insight?

[Fausto]

Hello @Mackenzie Cox.

Your screen capture shows all channels set to differential mode, except for channels 7 and 8.

What are your signal connections for all channels?

Please include even those channels without a signal.

Regards,

Fausto