Elma BM 251s-257s
side 26
Note:
*
Range-Lock and Function-Lock Feature:
When a measurement reading is being displayed in
AutoCheck
TM
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
TM
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
TM
mode provides low
(ramp-up) input impedance (approx. 2.5
kΩ 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
TM
mode input impedance increases abruptly from initial 2.5
kΩ 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
/ 2.5
kΩ), decreasing abruptly to approx. 3.8mA (1000V x 1.414 / 375kΩ) within a fraction of a second. Do
not use AutoCheck
TM
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.
Note:
*Input sensitivity varies automatically with function range selected before activating the Hz function. 6V
function range has the highest and the 1000V range has the lowest. It is recommended to first measure
the signal voltage (or current) level then activate the Hz function in that voltage (or current) range to
automatically set the most appropriate trigger level. You can also press the
RANGE
button momentarily
to select another trigger level manually. If the Hz reading becomes unstable, select lower sensitivity to
avoid electrical noise. If the reading shows zero, select higher sensitivity.
*Number of Bar-graph pointer is used to indicate input range (sensitivity) selected. 1/2/3/4 pointers
indicate 6/60/600/1000V, 6/10/-/-A, 60/600/-/-mA or 600/6000/-/-uA is selected in corresponding V, A, mA
or uA function respectively. (
“-” means range not available)
*The
Hz
of
mV
function is designed especially for logic level (3V or 5V family) frequency measurement.
!
DCV
JACK
JACK
ACV
!
JACK
JACK
!
JACK
JACK
Hz
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