This new Greyline Transmitter displays, controls and transmits level. Mount the non-contacting ultrasonic sensor at the top of your tank, and the compact, watertight electronics/display enclosure at a convenient location nearby. Operators can calibrate the LIT25 with its 2-button Keypad, without climbing the tank. Use the built-in relay for level control or alarm, the large 4-digit display for local indication, and the isolated 4-20mA output to to transmit level to a PLC.The standard ultrasonic Sensor measures liquid levels up to 32 ft. (10 m), and includes automatic temperature compensation. Choose the optional all-Teflon sensor for chemical compatibility, or one rated to 50 ft (15.6 m) range. All ultrasonic sensors are available with optional intrinsic safety for installation in hazardous rated locations. The LIT25 can also be ordered with gauge-type pressure sensors for special applications.
How It Works....
Greyline ultrasonic sensors are mounted at the top of a tank or in a position above the liquid being measured. The sensor continuously transmits pulses of high frequency sound (typically 42 kHz) which travel away from the sensor, hit the surface of the liquid and return to the sensor.
|The instrument electronics measure the time it takes from transmitted sound to return of the echo. With reference to the speed of sound in air, the exact distance of the liquid surface from the sensor can be calculated with high accuracy (±0.25% of maximum range).
Since the speed of sound is affected by air temperature, Greyline ultrasonic level sensors include a built-in temperature sensor. Level/distance measurements are automatically temperature compensated throughout the operating temperature range of the sensor.
The sensor should be positioned so that it has an clear "view" of the liquid surface and away from ladders, pipes or other obstructions. Greyline recommends 1 ft. from the sidewall for every 10 ft. depth (300 mm for every 3 m depth). False echoes from agitators (sweeping under the sensor), turbulence and waves can be filtered and disregarded by the instrument.
Greyline models range from simple 4-20mA level indicating transmitters, to sophisticated monitoring, controlling and logging models.
Standard features include:
- sensor - PZ32T, PVC and teflon, 32 ft / 10 m range
- sensor cable - 25 ft / 7.6 m coaxial
- enclosure - watertight, dust tight NEMA4X (IP67) polycarbonate
- programming - built-in 2 button keypad
- calibration - selectable Level or Range mode
- display - large 4-digit LCD
- temperature compensation - automatic
- output - isolated 4-20mA (1000 ohm)
- 1 signal Relay - 1 amp
- power input - 100-130VAC 50/60Hz, 5 watts maximum
- electrical surge protection
- sensor, AC power and 4-20mA output
- 1 Manual - Installation and Operation
LEVEL INDICATING TRANSMITTER SPECIFICATIONS
SCOPE: This specification covers a non-contacting, ultrasonic Level Indicating Transmitter as manufactured by Greyline Instruments Inc., Massena, New York / Long Sault, Ontario. The instrument shall provide for indicating, transmitting and control of the material level in a vessel, or proximity of a target to the Instrument Sensor.
A. PERFORMANCE SPECIFICATIONS
- To consist of a non-contacting ultrasonic sensor, connecting cable, and a remote enclosure with indicating, transmitting and controlling electronics.
- Measurement accuracy shall be ±0.25% of Range or 2 mm (0.08"), whichever is greater, and shall be automatically temperature compensated.
- Sensor cable shall be RG62AU coaxial with total length as required for installation, not to exceed 500' (152 m).
- System shall have no moving parts and shall not contact the material being measured.
B. NON-CONTACTING SENSOR
- Sensor shall be constructed of PVC and Teflon.
- The sensor shall have a minimum deadband or blanking of 12" (305mm) and a maximum range of 32 ft. (10 m), and have an operating frequency of 42 kHz with an ultrasonic beam angle of 8ø.
- Sensor shall withstand accidental submersion to 20 psi.
- Sensor operating temperature shall be from -40°F to 150°F (-40°C to 65°C).
- Sensor shall include integral temperature sensor. Temperature sensors requiring separate mounting and wire runs shall not be accepted.
C. SENSOR CONNECTING CABLE
- Provide RG62AU coaxial cable 25' (7.6 m) continuous length, with waterproof, potted bond to the Sensor head.
- Extended sensor cable shall be RG62AU coaxial to a maximum of 500' (152 m). Cable shall be spliced with screw terminal connections in manufacturer's recommended steel NEMA4 Junction Box.
- Level and temperature signals shall be conducted on one single coaxial cable. Separate or multiple-conductor cables shall not be accepted.
- Sensor cable shall be installed in grounded metal conduit.
D. INDICATING TRANSMITTER
- The Indicating Transmitter shall be housed in a wall-mount, watertight NEMA4X (IP66) enclosure with clear, polycarbonate cover. Mounting hardware shall be included. Combined Transmitter/Sensor systems requiring mounting at the top of a tank shall not be accepted.
- Transmitter shall include a large 4-digit LCD display with 3/4" (19 mm) high digits that shall be visible without opening the enclosure cover.
- The transmitter shall provide for field-calibration via built-in 2-key calibration system. Systems requiring calibration by BCD switches or external calibrators shall not be accepted.
- Calibration data shall be permanently stored through power interruptions without requirement of a back-up battery.
- Field calibration shall allow keypad selection of measurement span, Range or Level operating modes, and display units in Percent, Inches or Centimeters.
- Transmitter shall permit field programmable damping to smooth output in turbulent level conditions, and programmable rejection time to disregard false signals from agitators, waves and spurious echoes.
- Transmitter operating temperature shall be from -13°F to 122°F (-25°C to 50°C).
- Transmitter shall have an isolated 4-20mA output into a 1000 ohm maximum load. Output shall allow field programmable offsets of 4mA and 20mA.
- Provide one signal relay contact rated 1 amp. Relay shall be programmable for single set point alarm, pump control, and/or echo loss alarm.
- Transmitter electronics shall be surge protected on AC power input, sensor and 4-20 mA output.
- Transmitter power input shall be 120VAC 50/60Hz with power consumption of 5 watts or less.
E. ADDITIONAL FEATURES FOR INSERTION IN SPECIFICATION AS REQUIRED:
- Transmitter power input shall be 200-250VAC 50/60Hz with maximum power consumption of 5 watts or less.
- Transmitter power input shall be 24VDC with maximum power consumption of 5 watts or less.
- Have an all-teflon sensor Model PZ32TE rated for 32' (10 m) maximum range and operation from -40°F to 170°F (-40°C to 76°C).
- Have a PVC and Teflon sensor Model PZ52T rated for measurement range on liquids up to 50 ft. (15.6 m).
- Have a PVC sensor Model PZ80 rated for measurement range on liquids up to 80 ft. (25 m).
- Include manufacturer's recommended sensor cable Junction Box for extended cable lengths.
- Sensor, connecting cable and junction boxes shall be rated intrinsically safe to Class I,II,III, Div. I,II, Groups C,D,E,F,G.
The instrument shall be a Model LIT25 Ultrasonic Level Transmitter as manufactured by Greyline Instruments Inc., and warranted against defects in materials and workmanship for one year.