NI USB-6008/6009 Analog Input Reads Approximately -1.4V Offset with RSE Connections

Updated Nov 22, 2022

Reported In

Hardware

  • USB-6008
  • USB-6009

Driver

  • NI-DAQmx

Issue Details

When wiring an external signal to the NI USB-6008/6009 using the Referenced Single-Ended (RSE) terminal configuration (where the signal is connected to the Analog Input pin (AIx) and the GND pin), there is a constant DC offset of approximately -1.4V.

Solution

NI-DAQ™mx channel creation sets a default mode for the input terminal configuration. Thus, when using the RSE terminal configuration, you will need to explicitly specify it when creating a DAQmx task.

Using DAQ Assistant, you can set this by choosing the proper terminal configuration in the window below.



However, if you are using the NI-DAQmx palette, you can set this by configuring the Input Terminal Configuration input of the DAQmx Create Channel VI.

Additional Information

If you leave the terminal configuration unspecified, the operation will use differential mode by default. The NI USB-6008/6009 pins float to an approximate -1.4V offset. Thus, the readings with RSE terminal connections using the default mode will be skewed to that value.

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