Teledyne 4250 Installation And Operation Manual page 41

DO/PH READING INTERVAL refers to the measurement of spe-
cific aspects of the flow stream other than amount. 4250 Flow
Meters support measurement of three different characteristics:
temperature, pH (the relative acidity or alkalinity of a
solution), and D.O., dissolved oxygen.
Note
If you are using the Isco D.O. sensor or are sensing D.O. with
the YSI 600 Sonde, select as long a measurement interval as
is practical for your application. The reasoning is that the D.O.
sensor is turned off between measurement intervals and this
turned-off period prolongs the life of the sensor.
YSI 600 READING INTERVAL refers to the YSI 600 Sonde. The
flow meter can measure several different aspects of the stream at
the same time, including pH, D.O., temperature, plus conduc-
tivity.
If you select LEVEL READING INTERVAL, the following will
appear:
LEVEL READING INTERVAL
• CONTINUOUS • • 15 SEC • • 30 SEC • • 1 MIN • • 2 MIN • • 5 MIN •
The LEVEL READING INTERVAL option is a way to conserve
power in battery-powered installations. If your installation is
AC-powered, you can simply select CONTINUOUS. Consid-
erable power is expended in generating the ultrasonic
pulses in the level sensor.
Select the longest acceptable interval between readings if oper-
ating on battery power. If you need a faster response time, select
one of the shorter intervals. If operating on battery power, you
may have to seek a compromise between short reading intervals
and battery life expectancy.
If you select VELOCITY READING INTERVAL, the following
will appear:
VELOCITY READING INTERVAL
• CONTINUOUS • • 2 MIN • • 5 MIN • • 15 MIN• • 30 MIN •
Returning to the MEASUREMENTS menu, if you select
MINIMUM DEPTH, the following will appear:
MINIMUM DEPTH FOR VELOCITY MEASUREMENT
• 2 IN/50 MM• • 3 IN/75 MM• • 4 IN/100MM•
Standard and Extended Range Sensors – Three selections
are available for the minimum depth for velocity measurements:
2, 3, or 4 inches (50, 75, or 100 mm). The Minimum Depth is the
minimum amount of water above the bottom of the sensor that is
required to obtain a velocity reading. This depth varies with the
velocity of the flow stream; at higher velocities, the depth is
greater.
4250 Flow Meter
Section 2 Programming
2-13