1 Introduction28 Keysight U1273A/U1273AX User’s GuideIn auto-range, the multimeter selects the lowest range to display the highestavailable precision (resolution) for the input signal. If manual range is alreadyenabled, press for more than 1 second to enter the auto-ranging mode.If auto-ranging is enabled, press to enter the manual range mode.Each additional press of sets the multimeter to the next higher range,unless it is already in the highest range, at which point the range switches to thelowest range.Alerts and warnings during measurementVoltage alertYour multimeter provides a voltage alert for voltage measurements in bothauto-ranging and manual range modes. The multimeter starts beepingperiodically once the measured voltage exceeds the alert value (regardless ofpolarity) set in the setup menu.By default, this feature is turned off. Be sure to set the alert voltage according toyour test requirements. To change the alert voltage level, refer to “Enabling theovervoltage alert” on page 143.Hazardous voltage indicationThe multimeter will also display the hazardous voltage ( ) symbol as an earlyprecaution when the measured voltage is equal to or greater than 30 V in allvoltage measurement modes.NOTE The range is fixed for diode tests, temperature, and Z LOW measurements.AutoRangeAutoRangeAutoRangeWARNING For your own safety, please do not ignore the voltage alert. When themultimeter cautions you with a voltage alert, you are advised to take note ofthe high voltage existence and to use precautions when performingmeasurements.
