SCOPE: This specification
covers a portable Level-Velocity Logger as manufactured
by Greyline Instruments, Massena, New York / Long Sault,
Ontario. The instrument shall provide for measurement
and data logging of level, velocity and temperature readings
from flow in open channels and partially filled or surcharged
- Level-Velocity Logger
to consist of a submersible ultrasonic sensor, connecting
cable, and a remote enclosure with electronics and display.
System shall have no moving parts.
- Level measurement accuracy
shall be +/-0.25% of Level. Velocity measurement accuracy
shall be +/-2% of reading.
B. SENSING ELEMENT
- Ultrasonic sensor shall
be designed for continuous submersion in liquids.
- Using the ultrasonic
Doppler principle, the sensor shall measure fluid velocities
from 0.1 to 10 ft/sec (0.03 to 3.05 m/sec).
- Using ultrasonic echo-ranging
principle, the submerged sensor shall measure liquid
level from 1" to 15 ft. (25.4 mm to 4.57 m) above
the bottom of the pipe or channel. Minimum detectable
level shall not be greater than 1" (25.4 mm). Level
sensing circuitry shall include a temperature sensor
for automatic temperature compensation.
- Sensor shall be constructed
of PVC, polyurethane and epoxy.
- Sensor operating temperature
shall be from 5ºF to 150ºF (-15ºC to
C. SENSOR CONNECTING
- Provide minimum length
25 ft (7.6 m) tri-coaxial cable with potted bond to
the Sensor head. Sensor cable shall be waterproof and
electrically shielded. Exposed material shall be polyurethane
- Sensor shall include
a watertight plug for connection to the instrument electronics.
D. LOGGER ELECTRONICS
- No calibration shall
be required. The Level-Velocity Logger shall measure
liquid level from the bottom of the pipe or channel,
and flow velocity.
- Logger electronics operating
temperature shall be from -5º to 140ºF (-20º
- Shall have an isolated
RS232 output operating at 28,800 Baud to transfer log
files to a Windows™ computer or laptop.
- Provide an LCD bar graph
display to indicate level, velocity and temperature
readings, plus remaining battery and logger storage
- Shall be housed in a
watertight IP67 enclosure with hinged, latching cover
and watertight sensor cable entry.
- Logger capacity shall
be 130,000 data points. Each data point includes level,
velocity and temperature reading.
- Logger sample rate shall
be user-selectable from 10 or 30 seconds, 1, 2, 5, 10,
30 or 60 minutes.
- Shall be powered by
4 D-cell Alkaline batteries. Battery life shall be matched
to Logger storage capacity: 15 days at 10 second sample
rate up to 4 years at 30 minute sample rate.
- Shall include Windows™
software to retrieve, display, save and export log files
from the Level-Velocity Logger. Shall support Windows
versions including 98, 2000, Me, XP, Vista and 7.
- Shall convert level-velocity
readings to flow for channel shapes including round
pipes, rectangular, trapezoid and egg-shaped channels.
Shall convert level readings to flow for flumes and
- Shall provide 'real-time'
communication with the level-velocity logger to display
readings with a refresh rate of 10 seconds or less.
- Shall permit the operator
to set logging rate of the level-velocity instrument
from 10 or 30 seconds, 1, 2, 5, 10, 30 or 60 minutes.
- Shall display battery
life remaining and logger capacity remaining.
- Shall display, save,
output to a printer and export level-velocity log files
in graph and tabular format. Export log files shall
be delimited for import to spreadsheet or database programs.
- Shall permit conversion
of linear and volume units.
- Shall support RS232
connection through COM ports and USB to RS232 converters.
OPTIONAL FEATURES FOR INSERTION AS REQUIRED
- Shall include 50 ft
/ 15 m length sensor cable extension with watertight
connector plugs to permit sensor installation total
distance of 75 ft / 23 m from the electronics enclosure.
Cable extension shall be shielded, submersible with
a durable polyurethane coating.
Logger shall be Stingray model by Greyline Instruments
and warranted against defects in materials and workmanship
for one year.
shall be 'Greyline Logger' by Greyline Instruments.