ADS Environmental Services Model 3600 530002 A2 - Manual (Page 127)

Features and Specifications A-9
Doppler Velocity Subsystem
The following topic contains information about the Doppler velocity subsystem,
including the Doppler velocity sensor and digital specifications for the Doppler
velocity board.
Doppler Velocity Sensor
The following table contains information and specifications for the Doppler velocity
sensor.
Measurement
Technique
The ultrasonic Doppler frequency shifts measure changes in the frequency that
ultrasonic waves are transmitted upstream through the flow and received back after
reflection from particle matter. The received signals are processed through a digital
spectrum analyzer, and the resultant data is used to calculate average velocities.
Calculation is based on the principle of the Doppler effect.
Effective Range The effective range is -1.52 to +4.57 m/s(-5 to +15 ft/s).
Resolution The resolution is 0.012 m/s (0.038 ft/s).
Accuracy For readings of
0 to 1.5 m/s (0 to 5 ft/s), the accuracy equals 1.0% full scale (20 ft/s);
1.5 to 3.0 m/s (5 to 10 ft/s), the accuracy equals 1.5% full scale (20 ft/s); and
3.0 to 4.57 m/s (10 to 15 ft/s), the accuracy equals 3.5% full scale (20 ft/s).
Beam The sensor transmits an omnidirectional beam.
Housing
The housing dimensions are 38 mm (1.5 in.)
×
28.5 mm (1.125 in.)
×
12.7 mm (0.5 in.)
and made of molded PVC plastic.
Installation The sensor is installed in a sewer pipe on an expandable stainless steel ring below the
level of minimum flow and typically upstream of any hydraulic disturbances associated
with the invert.
Doppler Velocity Board Digital Specifications
The following table contains digital specifications for the Doppler velocity board.
Processor The Doppler velocity board uses an 80C31 CMOS microprocessor and a digital signal
processor.
Memory The EPROM has 64K bytes.
The RAM has 32K bytes.
Communications The Doppler velocity board uses a UART to communicate over a logic-level bus with the
processor board.
Functions The Doppler velocity board transmits velocity readings in feet per second to the
processor board.