6
Instruction Manual
2. Starting Measurement
2.1 Built-in Battery
The ultrasonic flow meter can operate either from the built-in Ni-H rechargeable battery,
which will last over 12 hours of continuous operation when fully recharged, or from an
external AC/power supply from the battery charger.
The battery charging circuits employ a scheme of constant-current and constant-voltage. It
has a characteristic of fast charging at the beginning and very slow charging when the
battery approaches to full recharge. Generally, when the green LED starts coming on, the
battery would be nearly 95% recharged and when the red LED is off, the battery would be
98% recharged.
Since the charging current becomes tapered when the battery recharge is nearly completed,
i.e. the charging current becomes smaller and smaller, therefore, there should be no
over-recharging problem. That means the charging progress can last very long. The
charger can be connected to the handset all the time when an around-the-clock
measurement is required.
When fully recharged, the terminal voltage reaches around 4.25V. The terminal voltage is
displayed on window M07. W hen the battery is nearly consumed, the battery voltage drops
to below 3V. The user can obtain an approximate battery working time from the battery
voltage.
A software battery working time estimator
is integrated in this instrument based on the
terminal voltage. Please note that the estimator may have relatively bigger errors in the
estimated working time, especially when the voltage is in the range of around 3.70 to -3.90
volt.
2.2 Power On
Press the ON key to switch on the instrument and press the OFF to turn off the power.
Once the flow meter is switched on, it will run a self diagnostic program, checking first the
hardware and then the software integrity. If there is any abnormality, corresponding error
messages will display.
Generally, there should be no display of error messages, and the flow meter will go to the
most commonly used Menu W indow Number 01 (short for M01) to display the Velocity,
Flow Rate, Positive Totalizer, Signal Strength and Signal Quality, based on the pipe
