Hach 910, Инструкция по эксплуатации инструмента

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Page 16
Choosing the Appropriate Meter and Sensor Combination
GettingStarted.fm
Section 1
1.3.2 Dealing with Difficult Sites
Some sites may be difficult to monitor due to poor site conditions. The
direction and the speed of the particles in the flow stream contribute to the
signal received by the velocity sensor. If turbulence near the measurement
point is excessive, it may be difficult for the sensor to determine the average
velocity of the stream. Hach loggers provide several unique features to help
deal with these problem sites. See Compensating for Velocity Direction in your
sensor manual.
1.3.3 Using the Proper Batteries
Use only Energizer EN-529, Alkaline, 6 V dc batteries. These batteries are
required to achieve the rated performance of the flow meter. Other batteries
will produce unacceptable results. See Battery Information on page 31 for
more information.
1.3.4 Mounting the Flow Meter with the Proper Orientation
You must mount the flow meter so that the connectors face down. The
end of the meter that contains the batteries should face up. If the connectors
face up, they may corrode and allow water to seep into the instrument.
1.3.5 Preventing Damage to the Flow Meter in a Harsh Environment
The connectors on your flow meter have protective caps. Cover the
connectors with the protective caps when not in use to prevent corrosion.
1.4 Choosing the Appropriate Meter and Sensor Combination
Use Table 2 to determine which sensors to use.
Table 1 Suggestions for Preventing Turbulence
Site Condition Suggested Remedy
Outfalls Attach the sensor at least ten times the maximum expected level upstream of the outfall.
Vertical drops in the
channel floor
Attach the sensor at least ten times the maximum expected level upstream of the vertical drop.
Attach the sensor at least ten times the maximum expected level downstream of the vertical drop.
Elbows, sharp turns, and
“Y” connections
Locate the sensor at least ten times the maximum expected level upstream of the impediment.
Locate the sensor at least ten times the maximum expected level downstream of the impediment.
Table 2 Flow Meter and Sensor Configuration Options
Flow Meter Model Level and Velocity Sensor Configuration Options
910 Meter plus one Submerged Depth/Velocity Sensor or one Velocity Only Sensor
920
Meter plus two Submerged Depth/Velocity Sensors
or
Meter plus one Submerged Depth/Velocity Sensor and one Ultrasonic 75 kHz Sensor
930 Meter plus up to three Submerged Depth/Velocity Sensors and up to two Ultrasonic 75 kHz Sensors