Applies to:

CMS units running software versions 1.5.0-1.9.0




CMS, Troubleshooting


Solution for error messages related to CMS Oscilloscope.

Error Message


Constant Monitoring System (CMS) application data locks up and displays an error message containing one of the following error descriptions:

  • niScope Initiate

  • niScope

  • niScope Multi Fetch

Upon clearing the error message, the CMS may go to a blue screen with an error code of “BAD_POOL_CALLER”.


The cause of this error message was due to a disruption in the communication between the oscilloscope and the cDAQ along the USB line. This disruption can be caused by excessive voltage input into the oscilloscope propagating through the USB line into the cDAQ, causing a lockup.

This issue can be resolved by installing 1) a voltage isolator (PN Entube DE-HB from Verivolt) on the input side of the oscilloscope and 2) a shielded USB cable with ferrites between the oscilloscope and cDAQ to replace the standard cable.


To date, the voltage isolators and shielded USB cable with ferrites have been installed on numerous Constant Monitoring Systems with a 100% success rate in terms of resolving the oscilloscope error messages.

Do you need more help?

Submit your questions or requests using the Support Ticket Submission form.

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