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NI PXIe-4112 turn-off problem



In a PXI test system, we are using a brand new PSU: NI PXIe-4112 2 Channel Power Supply, 60V, 1A, calibrated 4th juli 2019.


We have problems with the PSU turns off, both output channels diode turns red. This happens after about 12 hours allmost constant operation.


Both channels are biased, to 24V and 3.3V repectively. Load current less than 10mA. The PSU are in turn supplied by the Auxiliary Power Source, PXIe-411X, as intended.


Both channels are shorted to gnd at the failure. Restart of the test system is necessary to get going again.


We suspect that overheat is part of the problem, since our troubleshooting have shown that is takes longer time before failure when we run the PXI fan at highest speed. However, the fan at mode "auto" should do the job, sholdn't it?


Whe also know that we may have glitches at 230V mains from time to time. Are there any known sensitivity to such glitches?


Error message received after failure:

niDCPower Initiate.vi<ERR>Internal serial communication bus failed.  Try resetting the  device.  If the error persists, contact National Instruments.

Error code: -1074118635


Hoping for some input,



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Just to confirm my understanding, you are running a 4112 card with each channel generating 24V and 3.3V respectively. After around 12hours of connected to your external circuits, the Instrument panel LED turns RED and the output of the Power supply is turned Off (same as short to GND).


It would help further to understand the external circuit connections.


From the error, it seems to be an instrument hardware issue, it would be best to contact NI for RMA or repair support.

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