Water Level Monitoring

Application Background

Water level can be measured using any one of the methods below: The measurement methods include:

• Method 1 – a still well or still pipe with a shaft encoder with a float and beaded float line system.
• Method 2 – a pressure sensor which is immersed into the stream or river.
• Method 3 – the more complex pressure bubbler system which allows for a small open tube to be immersed into the stream or river with a gas pump or gas cylinder to inject small bubbles into the open tube and measure water depth by measuring the back pressure required to force bubbles out of the tube in the water.
• Method 4 – Measuring depth using Ultrasonics Doppler Instrument 6527.
• Method 5 – Measuring depth using Radar.

Application Detail

There are many measuring methods available, but still the most common method is a shaft encoder float and wheel system. This method requires a large well or a smaller pipe to be installed on the stream, river bank or on a bridge structure, to provide a stable, not disturbed by flow or wind, measurement environment.
A small float, a float line and a counter weight system will respond to depth/level changes in stream or river. That response causes rotation of the shaft of a wheel. Shaft rotation is measured very accurately by optical encoder and the data is simultaneously displayed and recorded in the data logger within the instrument.

The Unidata Model 6541 Precision Water Level instrument can achieve operating accuracy and resolution of 0.2mm. This accuracy is maintained for the service life of the instrument without calibration or maintenance, apart from battery changes. The 6541 instrument has the range to monitor surface and under- ground waters, and the precision to monitor rainfall and evaporation. The very low mechanical friction and inertia of the instrument means that it can produce data with high precision and accuracy. Unidata Precision Water Level Instruments have been installed at over 5000 sites. The power consumption of this instrument is tiny, only a few micro amps is needed to operate it, so it can be run on a single battery pack for more than a year.

The 6541 instrument is normally “connected” to the water surface by a float system. On installation, the instrument is set to display the water level. An optical encoder is mounted on the input shaft so, as the water level changes, the input shaft and encoder rotate. The rotation of the encoder is continuously monitored so the instrument tracks water level changes. These changes update the LCD display. Choice of encoding wheel diameter, length of float line and type of float will depend on the site conditions and measurement objectives.

A Water Level Instrument can be equipped with an internal micrologger that can store measured data or connected to a Neon Remote Logger to provide a temporary store of the data until it is transmitted to central Neon sever on a regular basis. When connected with a Neon Remote Logger you can monitor data recorded by the instrument and check the health of the site, all from a web browser on the internet.

This can be done over cellular or satellite communication links. Using telemetry decreases the need for time consuming site visits. When you use one of the telemetry options you may need to provide external power such as a solar panel, external battery and regulator.

Typical Configuration

Options for Application Specific Instruments / InputsUnidata Part NumberDescription
Water Level Instrument6541C-11WLI with 500mm Pulley & Alk Batt Metric (Imperial version available)
Float6541F-115WLI Float - Cylinder 115mm (other options available)
Float Line6541D-MWLI Beaded Floatline Metric (Imperial version available)

Options for Neon Telemetry - NRL / NRT / RTU / Field UnitsUnidata Part NumberDescription
Neon Remote Logger 16 Channels3016AOptions Available: 3G/4G Cellular, Ethernet, Globalstar, Inmarsat, Iridium SBD and LoRa
Neon Remote Logger 8 Channels3008AOptions Available: 3G/4G Cellular, Ethernet, Globalstar, Inmarsat, Iridium SBD and LoRa
Neon Remote Logger 4 Channels3004AOptions Available: 3G/4G Cellular
Neon Remote Logger 4 Channels M Series3004A-MOptions Available: 3G/4G Cellular, Ethernet, Microsatellite, Iridium SBD and LoRa
Cellular RTU 3G/4G2013F-AB03 / 2013F-AB04Neon Metering Module 3G/4G with Antenna and Li Battery
Cellular RTU 3G/4G - Industrial2016F-AB03 / 2016F-AB04Neon Remote Terminal 3G/4G with Antenna and Li Battery
Low Earth Orbit Satellite Globalstar2015F-AB0NRT Satellite Globalstar Modem with Antenna and three Li Batteries
Ethernet2017F-0B0-1 or 3NRT Ethernet with single or triple Ethernet Ports with three Li Batteries
Equatorial Orbit Satellite - Inmarsat2018F-AB0-1 or 3NRT Ethernet with single or triple Ethernet Ports with three Li Batteries
LCD Display2500ENRT LCD Display
NRT Field Termination Strip2103F2015F,2016F,2017F, and 2018F NRT FTS
NRT Firmware Option2303A-8M8M Extended Memory Option
NRT Firmware Option2303A-8M-CAM8M Extended Memory & Serial Camera Option
NRT Firmware Option2303A-CAMSerial Camera Option

Options for Neon Application Software - Customer ServerUnidata Part NumberDescription
Neon Application Software2302ANeon Server Software Licence Incl 5 NAL
Neon Application Software2302A-10Additional 10 NRT Access Licences
Neon Application Software2302A-20Additional 20 NRT Access Licences
Neon Application Software2302A-50Additional 50 NRT Access Licences

Options for Neon Application Software - Unidata ServerUnidata Part NumberDescription
Neon Application Software2301ANeon Data Initial Subscription Setup Fee
Neon Hosting Service2301A-01Neon Data Service Fee for 1-50 NRTs
Neon Hosting Service2301A-02Neon Data Service Fee for 51-100 NRTs
Neon Hosting Service2301A-10Neon Data Service Fee Metering

Options for Conventional Dataloggers / Field UnitsUnidata Part NumberDescription
Neon Remote Logger 16 Analog Channels / Touch Screen Display3016A-00016 Ch NRL (Superseded Prologger 7001D)
Neon Remote Logger 8 Analog Channels / Touch Screen Display3008A-0008 Ch NRL (Superseded Stalogger 6004D)
Neon Remote Logger 4 Analog Channels / Touch Screen Display3004A-0004 Ch NRL (Superseded Micrologger 8010C)
Starlog V4 Management Software6308A-AUEStarlog V4 Full Licence Key