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| 3/22/2019 2:47 PM | |
Joined: 10/16/2007 Last visit: 6/7/2023 Posts: 600 Rating:
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Hello, do you use the specific cable for the thermocouple? And do you connect the cable directly to analogue input? Regards |
| 3/22/2019 2:53 PM | |
Joined: 3/5/2014 Last visit: 8/5/2022 Posts: 5521 Rating:
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hi, did you check the accuracies and errors of the modules and thermocouples? What are the operational limits and the basic errors of analog inputs and outputs? hope this helps, regards, |
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FCK WAR! |
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| 3/22/2019 3:10 PM | |
Joined: 10/30/2012 Last visit: 2/25/2023 Posts: 56 Rating:
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I am using specific type of cable for both type of thermocouple. |
| 4/11/2019 2:12 AM | |
Joined: 3/28/2010 Last visit: 6/5/2023 Posts: 955 Rating:
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1. The real question is why the error is only 2.5°C low when Fixed Reference Temperature is selected for the K Type thermocouple. Table 4-7 in the module's manual defines "Fixed reference temperature": "The reference temperature of the thermocouple is set to 0 °C. As a result, no temperature compensation is performed." The applied test temperature signal should read low by whatever the temperature of the terminal block is. For instance, if the temperature of the terminal block is 15°C, then the applied input should read 15°C low when Fixed Reference temperature is selected, because the cold junction compensation (reference temperature) value is not being added to that channel's measured input value. For the error to be only 2.5°C low at Fixed Reference Temperature means that the temperature of the terminal block is only 2.5°C high. That's a cold site. Do you work with gloves on? Maybe I missed the part in the manual where a Fixed Reference Temperature value can be configured to some value other than 0°C, which would explain the error. 2. Type B thermocouple extension wire introduces error. Here's a statement from a thermocouple vendor. Note that the error is always low. [snip] If you actually use measurements at that test temperature, add the error back in as an offset. |
Last edited by: Jen_Moderator at: 4/11/2019 1:23:58 PMRemoved link and added file as an attachment. |
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