Why DAQmx DevSerialNum Displays Differently in LabVIEW Compared to NI MAX

Updated Aug 17, 2026

Reported In

Hardware

  • CompactDAQ Controller

Software

  • LabVIEW
  • Measurement & Automation Explorer (MAX)

Issue Details

I am reading cDAQ module serial numbers in LabVIEW using the NI-DAQmx property node DevSerialNum. The values returned in LabVIEW do not match the serial numbers displayed in NI MAX.
When I attempt to convert the serial numbers to hexadecimal format, the same converted value appears for all modules, and some serial numbers are missing leading zeros compared to the values shown in NI MAX.

Solution

The NI-DAQmx property DevSerialNum returns a 32-bit unsigned integer. LabVIEW displays this value in decimal format by default, while NI MAX displays the same value as an 8-character hexadecimal number. The values shown in both applications represent the same underlying number using different base representations.
If the same hexadecimal value is repeated for multiple modules, the hexadecimal conversion is typically performed outside the module iteration loop, or the dataflow wiring does not preserve a unique conversion for each module.
To display serial numbers in the same format as NI MAX:
 
  1. Open the VI block diagram that iterates through the cDAQ modules.
  2. Place the NI-DAQmx DevSerialNum property node inside the loop.
  3. Convert each serial number to hexadecimal format inside the loop using one of the following methods:
  4. Use the Number To Hexadecimal String function.
  5. Wire the DevSerialNum output to the function input.
  6. Wire a numeric constant of 8 to the width input.
  7. Use the Format Into String function with the format string:
    %08X
  8. Connect the hexadecimal string output to an auto-indexed tunnel on the loop boundary.
    Output the resulting array of 8-character hexadecimal serial number strings.
This formatting preserves leading zeros and produces serial number strings that match the format displayed in NI MAX.