03/01/16

8

ES51983

3 3/4 CAP AUTO DMM

any of the push function, except for HOLD, is pressed down. In addition, when RS232

output is active, the auto power-off function is also disabled. The APO sign on the LCD

panel indicates whether the auto power-off is enabled or not.

Note: Powering on the meter while pressing HOLD turns on all LCD segment until

HOLD is pressed again.

1.7 Frequency counter

The time base of the frequency counter is derived from an external crystal oscillator by

4000000

T

F

osc

where f

base when a 4MHz oscillator is used. The frequency counter can select the proper range

automatically or manually. Auto-range operation extends over five decades, from 4KHz

to 40MHz The following table summarizes the full scale range of the frequency counter.

Range

Full Scale

FR1

4.000KHz

FR2

40.00KHz

FR3

400.0KHz

FR4

4.000MHz

FR5

40.00MHz

1.8 Sleep

The meter enters sleep mode after auto power off. The SLEEP pin asserts low (-3V) in

the sleep mode, and asserts high (+3V, not 0V) after re-power on.

1.9 Re-power on

After auto power-off, pushing any of the push function or changing the rotary mode can

turn on the meter again. If the meter is re-powered on by changing the rotary mode, the

saved state is cleared. If the meter is re-powered on by push functions, the chip restores

the saved state and enters HOLD mode. The LCD displays the saved value.