How Do I Detect an Open Thermocouple Using the NI-9211? Hardware: CompactRIO>>Analog Input Modules>>NI 9211
Problem: I have read in the user manual for the NI-9211 that the module can detect open thermocouples. How do I program my application to work with this functionality? Solution: When the NI-9211 detects an open thermocouple, it pulls the channel to full-scale positive voltage. You must manually detect this in your application by monitoring each channel for extremely high temperature inputs. For example, the following screen shot is from reading two thermocouples:  You will notice that both channels are initially reading room temperature. When the thermocouple in channel 1 is removed, the channel is pulled to positive full-scale voltage and the channel reads over 1400 degrees Celsius. You can create a subVI that routinely scans through all thermocouple channels and returns a warning when the channel is above a predetermined limit. You can determine what this limit is based on your application. Related Links: NI-9211 Operating Manual Attachments:
Report Date: 11/02/2007 Last Updated: 11/02/2007 Document ID: 4F18TATS |
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