|
|
|
|
|
|
|
|
 |
|
||||||
|
Water Level FAQ Q: Are there any special application considerations for using the Thalimedes in surface water measurements? A: It is quite common to use the Thalimedes in surface water measurements. In order to use the Thalimedes shaft encoder for surface water, the application will require a water stilling well.
Q: What types of data logging or telemetry does the Thalimedes offer? A: The Thalimedes will communicate directly with a modem. The system has the ability to control commonly used modems such as GSM, Landline, and Cellular technologies. Alternatively, the Thalimedes has an onboard data logger that can hold 30,000 readings.
Q: How is the Thalimedes powered? A: The Thalimedes is available with or without an internal battery. The internal battery (standard C-cell) can last up to 15 months in most applications. The Thalimedes without an internal battery requires an external 12v power source.
Q: What size of well diameter would I need in order to use the Thalimedes? A: The Thalimedes will operate in 4-inch diameter and larger well sizes.
Q: What exactly is the "bubble-in" principle and how does it work? A: A piston pump inside the instrument enclosure generates compressed air, which flows through a dedicated line into the bubble chamber at programmable intervals, where it bubbles out uniformly into the groundwater. Depending on the groundwater level (h) above the bubble chamber orifice, an air pressure equal to the hydrostatic pressure (p) is established inside the measuring tube. p = ρ · g · h Assuming a constant liquid density, there is a linear relationship between the water level to be measured and the air pressure inside the measuring tube. The bubble-line pressure and the barometric pressure are measured concurrently by an absolute pressure-measuring cell inside the instrument enclosure. The water level is calculated as the difference between the two signals. This measuring method prevents a potential zero-point drift of the measuring cell from influencing the accuracy of the instrument. The sage of an absolute pressure-measuring cell makes the instrument completely unaffected by humidity and condensation.
Q: What are the advantages to "bubble-in" technology? A: The primary advantage to this technology is that it is drift free. Adverse affects such as temperature fluctuations are non-existent with the bubblers. In addition to being drift free, the sensors are typically located out of the water, lessening possible damage or flooding of the instrumentation.
Q: How far down does the bubble pot need to be placed? A: The bubble pot, located on the end of the bubble tubing, must remain below the water level at all times.
Q: Is the Orphimedes better suited for ground or surface water level measurement? A: The Orphimedes is designed for ground water applications only and is not suitable for superficial water.
Q: What size well will the Orphimedes fit in? A: The Orphimedes can be placed in 2 inch or greater well diameters.
Q: How does the instrument store data and how many reading can be held? A: The instrument stores data using ring memory (first in first out) and can hold 52,000 readings.
Q: What exactly is the "bubble-in" principle and how does it work? A: A piston pump inside the instrument enclosure generates compressed air, which flows through a dedicated line into the bubble chamber at programmable intervals, where it bubbles out uniformly into the groundwater. Depending on the groundwater level (h) above the bubble chamber orifice, an air pressure equal to the hydrostatic pressure (p) is established inside the measuring tube. p = ρ · g · h Assuming a constant liquid density, there is a linear relationship between the water level to be measured and the air pressure inside the measuring tube. The bubble-line pressure and the barometric pressure are measured concurrently by an absolute pressure-measuring cell inside the instrument enclosure. The water level is calculated as the difference between the two signals. This measuring method prevents a potential zero-point drift of the measuring cell from influencing the accuracy of the instrument. The usage of an absolute pressure-measuring cell makes the instrument completely unaffected by humidity and condensation.
Q: What are the advantages to "bubble-in" technology? A: The primary advantage to this technology is that it is drift free. Adverse affects from temperature fluctuations and barometric changes are non-existent with the bubblers. In addition to being drift free, the sensors are typically located out of the water, lessening possible damage or flooding of the instrumentation.
Q: Is the Nimbus better suited for ground or surface water level measurement? A: The Nimbus can be used for both applications. Typically the system is used in surface water while the Orphimedes is used for ground water. However, coupled with a micro station, the Nimbus can easily be adapted for groundwater applications, especially when telemetry is needed.
Q: What types of communication or telemetry does the Nimbus offer? A: The Nimbus will communicate directly with a modem. The system has the ability to control modems using technologies such as GSM, Landline, and Cellular. Alternatively, the Nimbus has an onboard data logger that can hold 400,000 readings.
Q: Is the Nimbus SDI-12 Compliant? A: Yes. The Nimbus can be configured as a fully SDI-12 compliant sensor and may be used with any common data logger including the OTT LogoSens.
Q: What is the diameter of the OTT pressure sensor? A: The OTT pressure sensor is approximately 3/4 inches in diameter, and will easily fit down a one inch well.
Q: What sorts of outputs are available? A: The OTT pressure sensor will communicate via the SDI-12 standard digital line (water level and temperature) as well as a 4-20 m/A analog line (water level).
Q: What is the FAD box and do I need one? A: The OTT PS 1 pressure probe is connected to the FAD 4 P humidity absorber by a flexible, longitudinally stable cable that contains a pressure compensating capillary tube for the atmospheric pressure. This serves as a connecting point for signals going on further, for connection to external data loggers.
Q: How is the instrument configured? A: The instrument is configured via SDI-12 commands.
Q: Does the OPS measure level or pressure? A: The OPS measures the pressure as well as the temperature. The gravity constant at your measurement site can them be entered manually, which allows the OPS to calculate the water level, which is then reported as the output value.
Q: What level ranges are offered? A: The OTT pressure sensor can be purchased in 5 ranges: 0 to 5m, 0 to10m, 0 to 20m, 0 to 40m, and 0 to 100m.
Q: What is the OTT RLS? A: The RLS is a non-contact level measurement sensor that uses impulse radar technology. The RLS was designed specifically for surface water level measurements.
Q: What is the difference between the pulse and the FMCW (Frequency Modulated continuous Wave) measurement? A: • FMCW - constant signal – requires more power.
Q: What maintenance is required? A: The RLS's bottom plate should be inspected regularly and if needed cleaned to remove build-up of dirt. Use a damp non-abrasive cloth or sponge to clean the sensor and if needed a mild soap.
Q: Is it possible to set the 4…20mA output range, and how? A: Yes, via SDI-12 extended commands.
Q: What is the maximum cable length? A: • 3,300 ft. via RS-485
Q: What is the shortest measuring interval? A: 20 seconds.
Q: What is the beam width/angle? A: 12°/±6°.
Q: What is the range for the power supply? A: 9.6 V DC to 28 V DC.
Q: 4…20mA Output: How often is the measured value updated? A: Every 20 seconds.
Q: 4…20mA Output: Is the measurement triggered by closing the loop? A: No.
Q: What is the protection class of the housing? A: IP67, but the OTT RLS is protected against short over flooding through a diving bell principle which protects the electronic (48h / 1m).
|
||||||
 |
 |
|||
 |
 |
 |
 |
|
|
||||
