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What does a 991 error code on a Circuit Monitor 2000 (CM2000 / CM2) display mean?

Published date: 28 December 2018

CM2000 Series meter's front display shows an alarm code "991" and user may not know what that means and how to fix it.

Product Line
CM2000, CM2050, CM2150, CM2250, CM2350, CM2450

Alarm code, Error Message, Power meter retrofit and replacement
If the front display of a Circuit Monitor 2000 displays a 991 message, this indicates an internal memory failure.

It is possible that re-loading the latest firmware for the meter could correct the issue. If a firmware refresh does not correct the error, the unit will need to be replaced.

The latest firmware for a CM2000 Series meter can be found in FA221408.

See FA237920 for information on how to upgrade the CM2000 firmware and for a link to the firmware download utility, DLF-3000. 

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