4210 Flow Meter
Section 3 Installation
3-6
The 4210 does not have any special requirements for mounting.
It may be located on any relatively flat surface either horizon-
tally, supported by the two mounting pads and the stainless steel
mounting bracket, or vertically, supported by the two plastic rails
on the bottom of the case. The flow meter may also be panel
mounted, using the mounting bracket on the top rear of the case
or suspended from a ladder rung or hook using the optional sus-
pension harness. To use the suspension harness, the carrying
handle should first be installed on the flow meter as described
above. Then slip the loops on the ends of the harness cables onto
the handle hooks. The flow meter may now be suspended using
the harness.
3.3.3 Safety Considerations In field installations of 4210 Flow Meters and associated
equipment, the safety of the personnel involved should be the
foremost consideration. No project is so important or deadline so
critical as to justify the risk of human life. Refer to the sections
on working safely in manholes and avoiding hazardous gases;
these sections are found at the back of this manual.
WARNING
The 4210 Flow Meter has not been approved for use in
“hazardous locations” as defined by the National Electrical
Code.
3.4 Error Factors It is possible for the ultrasonic measurement system to be in
error due to the influence of various factors on both the initial
pulse and reflected sound wave. It is important that you under-
stand these factors and take them into consideration when
planning an installation. Proper installation will result in more
accurate measurement.
The factors affecting the ultrasonic system may be grouped
broadly into two classes:
3.4.1 Velocity Errors These errors occur when the flow meter is unable to accurately
calculate the velocity of sound. Without going into the cause, it
may be said that they are proportional errors, in that the error
increases as the distance between the ultrasonic level sensor and
the liquid surface increases.
3.4.2 Echo Detect Errors These errors come from problems the flow meter may have mea-
suring the time between transmitting the ultrasonic pulse and
receiving the echo. Anything that can absorb the sound causes
these errors. This makes the echo amplifier detect the returned
signal either later or earlier than intended by the design of the
ramp-gain amplifier. These errors will generally be of an
absolute nature; they will not be affected to any extent by the
distance between the transducer and the water.
3.4.3 Error Factors and Flow
Meter Compensation
Following are specific factors affecting the accuracy of the 4210
Flow Meter and the measures provided for compensation of the
more significant factors.
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