HT HT78, User Manual, Page: 27 / 72

HT78
EN - 7
4.2. DESCRIPTION OF PARTS
4.2.1. Range and ON/OFF selector
Rotate the function selector from “ OFF ” position to any other position to turn on the meter.
Rotate again the selector to “ OFF ” position to switch off the meter
4.2.2. D-H key
Press D-HOLD key to enable Data HOLD feature. The “DH” message is shown and the
measured value is frozen on the display. Press the same key to exit from the function.
4.2.3. FILTER selector
Move the “ FILTER ” selector to enable (ON) or disable (OFF) the “Low-pass 150Hz filter”
during an AC current measurement. In this condition a low-pass filter with cut-off frequency
of 150Hz is active on meter in order to reduce the harmonic components of input signal. It
is reccomanded always to eneable this feature to perform accurate and stable
measurement of leakage current
4.2.4. LOCK selector
While slowly closing CT during the measurement on strong magnetic fields generated by
big currents, there might be a case where CT cannot be closed completely. In this case
use the
LOCK selector to lock/unlock the jaws of clamp durino a measurement
4.2.5. AutoPowerOFF
In order to preserve the internal batteries, the meter automatically switch off after about 10
minutes of idleness. Press the
D-H key or turn on again the meter after 10 second from
switch off to restore of normal functionality.
The AutoPwerOFF feature is automatically disabled by the meter during the connection to
DCV analogical output bt external datalogger