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Regina MerrittAug 1, 2025
What to do if McCrometer Ultra Mag Measuring Instruments shows 420 ERR?
- DDebra TurnerAug 1, 2025
If your McCrometer Measuring Instruments display shows a '420 ERR' message, it means the 4-20 circuit is not wired correctly. To fix this, check the wiring diagram and make sure 9-30VDC power is supplied to the circuit. Remember that the output is not source powered.