Unidata Dataloggers & Product Range

Unidata specialises in the design, manufacture, supply and support of products and solutions for environmental monitoring and industrial measurement. Products and systems range from acquisition devices, to standalone and IP (Ethernet, cellular and satellite) connected loggers, through to web based logging and analysis tools. The extensive range of products are most typically available ex-stock to ensure a fast turnaround on orders.

Unidata products can be configured to provide solutions for most environmental monitoring and industrial measurement requirements. Outlined in systems section are a number of systems that are common in the industry. However, Unidata and its partners pride themselves on finding solutions to their customers’ requirements and so they are always pleased to discuss specific requirements and how Unidata products can meet them.

For convenience, we have provided Application notes for our products, and we have listed our all Products by Group

This is How We Do It

Water Flow Monitoring System

Unidata’s Starflow Ultrasonic Doppler System 6526J is ideal for smaller open channel and pipe measurements as it is a complete hydrographic data collection system. It operates in a wide range of water qualities from fresh streams to primary sewerage channels. It measures both forward and reverse flows, and is particularly useful at sites where a stable stage/ velocity relationship does not exist.

Starflow measures water velocity, depth, flow and temperature, enabling you to do a complete stream study with a single instrument. For very small flow monitoring the Unidata tipping bucket flow gauge can be used 6506G/H.

Open channels, partly filled pipes, and natural streams have very complex velocity characteristics. Turbulence, waves, stream slope, bed and wall unevenness, rocks and debris, all combine to create an unpredictable velocity profile.

To account for these effects Starflow analyses up to one thousand separate velocity measurements and statistically determines the mean velocity. This approach provides a good “average velocity” even under difficult conditions.

The Starlog V4 companion software allows a user to define the stream, channel or pipe profile, so that the velocity and depth readings can be converted to a true flow reading.
Starflow contains a micrologger with 512kB of memory; enough for 250,000 measurements. It will acquire instantaneous, maximum, minimum and averaged readings. Starflow is equipped with the SDI-12 communications facility, intelligent battery supervision, and an interface to a telemetry system, such as Neon. By connecting a rain gauge 6506C you can make a complete storm water monitoring system.

Water Level Monitoring System

There are several different methods used to measure water level.
The measurement methods include:
1 – a still well or still pipe with a shaft encoder / float and wheel / beaded float line system
2 – a pressure sensor which is immersed into the stream or river
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

There are also emerging technologies such as radar and ultrasonic which can be used to measure water depth.

While there are many methods / technologies available, the most common and the most stable method is the shaft encoder float and wheel system. This method required a large well or a smaller pipe to be installed on the stream or river bank or on a bridge structure to provide a stable / not disturbed by flow or wind measurement environment for a small float, a float line and a counter weight so the movement in stream / river level can be measured by rotation of the shaft of a wheel. Typically the shaft rotation is measured very accurately by light or laser encoder, and the data is shown on the display and is recorded in the data logger within the instrument.

The Unidata 6541C Precision Water Level Instrument is a very accurate shaft encoder instrument, which has an LED display for the water level, as well as an internal data logger so water level readings can be recorded every 1, 5 or 10 minutes as required. When a Neon Remote Terminal or Module is added, the water level information can be transmitted over the internet to a central Neon server to allow authorities view the data on the web in near real time.

Surface Water and Groundwater Monitoring System

Surface water monitoring equipment measures surface water quality and quantity and transmits the information via cell phone or satellite to a central Neon Server where it can be analysed to make meaningful water management decisions.
Such systems may include instruments to measure water flow 6526J, water depth 6542D, water quality for example electroconductivity 6536E-6536P-2-X and pH 6528C in small open channels and storm water drains and channels.

Surface water movement may also be monitored into and out of small dams and ponds in agricultural areas. For large pipes and small open channels, an ultrasonic velocity and depth meter can be used to measure occasional flows (during rain periods for example) and also test the water quality of such occasional flows.

Groundwater depth is measured with a small diameter sensor deep in an observation bore hole. Water depth can be measured with a pressure sensor lowered down the bore hole and immersed in the water 6542D. This is call hydrostatic depth method. Alternatively a standard float-and-pulley sensor system with a small float and a pulley at the top of the bore hole can also be used to measure depth 6541C.

The hydrostatic depth method is widely used as it is convenient to install, however all pressure sensors have some drift which needs to be considered. The float and pulley method is less convenient, especially is narrow diameter bore holes of 100mm, but it is very accurate and is not subject to drift.

A Neon IP Data Logger/RTU/NRT needs to be added at the top of the bore and data recorded and collected manually, or the data can be telemetered to a central location on a regular, perhaps 4 hourly basis.

Application Notes

Application Note Water Flow Monitoring
Simply recording water depth does not provide a reliable measure of water flow, for example, depth may vary while flow remains constant. In such cases it is essential to measure depth and velocity and then determine the flow measurement.

Application Note Irrigation Channel Measurement and Control
Open-channel irrigation water intakes can be monitored for water level / flow and they can be optionally controlled by opening and closing a gate to deliver programmed flow.




Application Note Water Level Monitoring
While there are many methods / technologies available, the most common and the most stable method is the shaft encoder float and wheel system

Application Note Evaporation Monitoring
The rate of evaporation is defined as the amount of water evaporated from a unit surface area per unit of time. This parameter is an important indicator of the need for water of agricultural areas and also for hydrologists to monitor the water balance of an area.




Application Note Flood Monitoring
Early warning of flood conditions is vital to avoid any personal safety incidents and to mitigate damage to crops and infrastructure generally.


Application Note Water Quality Monitoring
Water quality measurements are performed for water in streams, rivers, lakes and in the groundwater system, using bore holes.