NI DMM Error -1074118625: Volt-Hertz Common Mode Limit Has Been Exceeded

Updated Nov 3, 2017

Issue Details

I am using an NI DMM, and occasionally run into the following error:

Error -1074118625: niDMM Read Waveform (waveform data).vi. The Volt-Hz common mode limit has been exceeded.

What does this error mean, and what can I do to remedy it?


The error usually occurs when the DMM encounters a high frequency, common mode power or voltage spike.

To restore functionality, you can reset the DMM. This can either be done manually in Measurement & Automation Explorer (MAX), or programmatically by using the niDMM Reset, Initiate, Read, or Read Multi Point VIs. Alternatively, you may measure the transient using an oscilloscope rather than a DMM. Also you can try to remove the common mode transient by using low-pass filtering or a common-mode choke.

For a common-mode choke, the wires should be wrapped around the choke several times, and both leads from the DMM can be run through the same choke.
In this image, one of the DMM leads is shown as 1, and the choke is shown as 2.

Additional Information

Exceeding the Volt-Hertz limit causes a short-term communication error with the internal FPGA of the DMM. High-frequency signals are a fairly common occurrence if you are switching high voltages, due to debouncing. NI DMM isolation barriers are primarily capacitive, so they are susceptible to high frequency signals. The Volt-Hertz limit is specified in the specifications for each DMM. For example, the NI PXI-4070 Specifications state the maximum Volt-Hertz product is 8 × 10^7 V-Hz.  


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