Analog Input (AI) data incorrect on NI cDAQ-9179

Updated Dec 14, 2017

Reported In

Hardware

  • cDAQ-9179

Driver

  • NI-DAQmx 15.1
  • NI-DAQmx 15.1.1
  • NI-DAQmx 15.5
  • NI-DAQmx 15.5.1

Issue Details

Why am I seeing incorrect data from my AI task when using a cDAQ-9179?

Solution

There is a bug in NI-DAQmx 15.1, 15.1.1 and 15.5 which causes this issue. Therefore you will need to update your DAQmx driver to 15.5.1 or later to fix this issue. You can download the latest versions of all NI drivers at ni.com/drivers.

Additional Information

NI has discovered a driver software issue where a DAQmx analog input task that configures modules installed in a cDAQ-9179 can return incorrect data.

For periodic waveforms, it should be easy to determine whether or not your data is affected. For noise measurements or unpredictable signals, it may not be obvious. To determine if data you've acquired with your cDAQ-9179 is affected, consider the conditions below.

For the purposes of this consideration, the cDAQ-9179 can be divided into two chassis segments (slots 1-7 and slots 8-14), and those segments can each be split into four slot groups (1-2, 3-4, 5-6, 7 and 8-9, 10-11, 12-13, 14). The data returned by your task is incorrect only if all of the following are true.
  • The task is run on an installation of NI-DAQmx version 15.1, 15.1.1, or 15.5.
  • The task configures only modules included in this list: NI 9201, NI 9203, NI 9205, NI 9206, NI 9215, NI 9220, NI 9221, NI 9222, NI 9223, NI 9381.
  • The total number of channels configured within a slot group is an odd number.
    • Multiple such slot groups exist within the same chassis segment.
If your task fits these criteria, then you can assume that all data returned by the task is incorrect. If your task is run on a different driver version, includes a module not listed, or has fewer than two slot groups per segment with odd channel counts, then the data returned is not affected.

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