Matco Tools MD251 Guia Del Usuario página 9

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*Note: When measuring a 3-phase system, special attention should be taken to the phase-to-
phase voltage which is significantly higher than the phase-to-earth voltage. To avoid exceeding the
voltage rating of the protection fuse(s) accidentally, always consider the phase-to-phase voltage as
the working voltage for the protection fuse(s).
Electric Field EF-Detection
At Volt or Current function, press the EF button for one second or more and release to toggle to
EF-Detection feature. The meter displays "E.F." when it is ready. Signal strength is indicated as a
series of bar-graph segments on the display plus variable beep tones.
• Non-Contact EF-Detection: An antenna is located along the top-right end of the meter, which
detects electric field surrounds current-carrying conductors. It is ideal for tracing live wiring
connections, locating wiring breakage and to distinguish between live or earth connections.
• Probe-Contact EF-Detection: For more precise indication of live wires, such as distinguishing
between live and ground connections, use the Red (+) test probe for direct contact measurements.
Hold
The hold feature freezes the display for later view. Press the HOLD button momentarily to toggle
the hold feature.
Relative Zero ( ) mode
Relative zero allows the user to offset the meter consecutive measurements with the displaying
reading as the reference value. Practically all displaying readings can be set as relative reference
value including MAX/MIN feature readings. Press the REL button momentarily to toggle relative
zero mode.
Manual or Auto-ranging
Press the RANGE button momentarily to select manual-ranging, and the meter will remain in the
range it was in, the LCD turns off. Press the button momentarily again to step through the
ranges. Press and hold the button for 1 second or more to resume auto-ranging.
Note: Manual ranging feature is not available in Hz and functions.