Why Am I Getting an Unexpected Reading With My NI-9211? Hardware: CompactRIO>>Analog Input Modules>>NI 9211
Problem: I am using a NI-9211 to read a thermocouple or other low-voltage signals. My signal is within the ±80 mV specification of the NI-9211. Why am I not reading the expected input temperature or voltage? Solution: You may be reading a value that is not expected because the Channel-to-COM voltage is not within the specifications of the NI-9211. The maximum common-mode voltage range for Channel-to-COM voltage is ±1.5 V. If you exceed the common-mode voltage range, the NI-9211 will read data that is wrong, although it may not be completely obvious that the reading is bad. See the tutorial on Field Wiring and Noise Considerations for Analog Signals for additional information on proper wiring for data acquisition. Related Links: Product Manuals: NI-9211 Operating Instructions (August 2006) Developer Zone Tutorial: Field Wiring and Noise Considerations for Analog Signals AE KB 3SQCSCRY: Temperature Readings With NI-9211 Are Off By Some Degrees Attachments:
Report Date: 08/17/2007 Last Updated: 11/11/2008 Document ID: 4CGCJ9TS |
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