Modules in Ethernet cDAQ Chassis Are Not Recognized in MAX

Updated Apr 24, 2023

Reported In


  • cDAQ-9181
  • cDAQ-9184
  • cDAQ-9185
  • cDAQ-9188
  • cDAQ-9189
  • NI-9401


  • NI-DAQmx

Issue Details

Every time I connect my Ethernet cDAQ chassis to my computer or restart my computer, the chassis appears in NI Measurement and Automation Explorer (MAX) but there are either no modules listed underneath it or there is a red "X" next to the modules inside of it. Why are the modules not automatically recognized and how can I fix this?


This behavior is caused by the Ethernet cDAQ chassis not being automatically reserved by the computer. A more thorough explanation of this behavior is included in the Additional Info section. Two solutions for getting the chassis to be reserved by the computer are listed below.

  • You can select the chassis in NI MAX and click the Self-Test button to perform a self-test, which will reserve the chassis and should cause the modules in the chassis to populate properly.
  • If programming the device in LabVIEW, you can use the DAQmx Reserve Dev VI to programmatically reserve the chassis at the start of each VI to ensure the computer has reserved it properly.

Additional Information

With a USB cDAQ chassis, plugging in the chassis or rebooting the computer will automatically reserve that chassis for use with that computer. However, with an Ethernet cDAQ chassis such as the cDAQ 9181/84/85/88/89, rebooting the computer or reconnecting the chassis does not automatically reserve the chassis for use with that computer. The purpose of not automatically reserving the chassis is for the case that the chassis is currently reserved or in use over the local network by a different computer.

Typically, restarting the computer will just show the chassis in NI MAX with no modules listed. If a module had been configured with a chassis in the past though, NI MAX will recognize that there should be a module in this chassis configuration and therefore shows a red "X" next to the module to signify that it is disconnected.