2. Measurement
2.1 Built-in Battery
The instrument can operate either from the built-in Ni-H rechargeable battery, which will last
over 8 hours of continuous operation when fully charged, or from an external AC/power
supply from the battery charger. When the red LED is on, the battery is charging.
The battery-charging circuit employs both constant-current and constant-voltage charging
methods. It has a characteristic of fast charging at the beginning and very slow charging when
the battery approaches to full charge.
Since the charging current becomes tapered when the battery charging is nearly completed
(i.e. the charging current becomes smaller and smaller), there should be no over-charging
problem. This also means the charging progress can last very long. To get close to 100%
power, charge the device overnight. The charger can be connected to the handset all the time
when an around-the-clock measurement is required.
When fully charged, the terminal voltage reaches around 4.25V. The terminal voltage is
displayed on window M07. When the battery is nearly consumed, the battery voltage drops to
below 3V. The approximate remaining working time is indicated in this window as well.
Notice that the battery remaining working time is estimated based on the current battery
voltage. It may have some errors, especially when the terminal voltage is in the range from
3.70 to 3.90 volts.
For battery maintenance and replacement, please refer to Appendix §8.1.
2.2 Power On
Press ON key to turn on the power and press OFF to turn off the power.
Once the flowmeter is turned 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 be displayed.
Generally, there should be no display of error messages, and the flowmeter will go to the most
commonly used Menu Window #01 (M01) to display the Velocity, Flow Rate, Positive
Totalizer, Signal Strength and Signal Quality, based on the pipe parameters configured last
time by the user or by the initial program.
The flow measurement program always operates in the background of the user interface. This
means that the flow measurement will keep running regardless of any user menu window
browsing or viewing. Only when the user enters new pipe parameters will the flowmeter
change measurement to reflect the new parameter changes.
When new pipe parameters are entered or when the power is turned on, the flowmeter will
into a self-adjusting mode to adjust the gain of the receiving circuits so that the signal strength
will be within a proper range. By this step, the flowmeter finds the best receiving signals. The
user will see the progress by the number 1, 2, or 3, located on the lower right corner of the
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