Operation Manual

Elma BM 251-252-255-257

side 39

Note:

Range-Lock and Function-Lock Feature:

When a measurement reading is

being displayed in AutoCheck

mode, press the RANGE or SELECT button momentarily

1 time can lock the range or function it was in. Press the button momentarily repeatedly to

step through the ranges or functions.

*As Hazardous-Alert: When making resistance measurements in AutoCheck

mode, an

unexpected display of voltage readings alerts you that the object under test is being

energized.

Ghost-voltage Buster:

Ghost-voltages are unwanted stray signals coupled from

adjacent hard signals, which confuse common multimeter voltage measurements. Our

AutoCheck

mode provides low (ramp-up) input impedance (approx. 2.5kΩ at low

voltage) to drain ghost voltages leaving mainly hard signal values on meter readings. It is

an invaluable feature for precise indication of hard signals, such as distinguishing between

hot and open wires (to ground) in electrical installation applications.

WARNING:

AutoCheck

mode input impedance increases abruptly from initial 2.5kΩ to a few hundred

kΩ’s on high voltage hard signals. “LoZ” displays on the LCD to remind the users of being

in such low impedance mode. Peak initial load current, while probing 1000VAC for

example, can be up to 566mA (1000V x 1.414 / 2.5kΩ), decreasing abruptly to approx.

3.8mA (1000V x 1.414 / 375kΩ) within a fraction of a second. Do not use AutoCheck

mode on circuits that could be damaged by such low input impedance. Instead, use rotary

selector or high input impedance voltage modes to minimize loading for such circuits.

DCV, ACV, & Line Frequency functions

Press the Hz push-button for one second or more to activate or to exit Hz.

DCV

JACK

ACV

JACK