The meaning of "OPEN" displayed when a multimeter tests a diode
The range and resolution for diode testing are fixed. Outputs 1 mA during testing (with 1 mA current source output).
The multimeter beeps when the signal is at the 0.3 to 0.8 V threshold (unless the siren is disabled). If the signal is greater than a certain voltage, "OPEN" is displayed on the front panel. Different multimeters have different voltage thresholds, such as Keysight's multimeter 3446XA is 5V, 34401A and 34411A are 1.2V.
