Standards to follow

When drafting technical specifications for the sensors used in level and flow measurement at dams, ponds, rivers and canals, in drinking water analysis systems, meteorological stations and multi-parameter groundwater systems, and for managing the data they produce, certain procedures and principles need to be set.

A monitoring station should be able to observe at the same time the reservoir level, water quality, water temperature, the flow through each of the dam's penstocks and the weather around the dam. Several institutions have prepared protocols that set standards for collecting and using such data and have added them to their technical specifications. The most influential recent example is the OSOS (Automatic Meter Reading System) protocol.

OSOS (Automatic Meter Reading System)

OSOS is one of the leading components of this control centre.

The Automatic Meter Reading System makes consumer-side electricity meters capable of remote communication so that their data can be monitored from a single centre.

Benefits of OSOS

• Consumption is read hourly every day, so possible errors can be caught before the end of the month.
• Current and voltage outage data reveal faults in the metering system, such as current and voltage transformer failures, so that they can be fixed quickly.
• Subscriber complaints caused by system errors are resolved faster and more reliably.
• The interface lets subscribers and suppliers follow their energy consumption.
• Load profiles from field meters support consumption analysis and demand forecasting by consumer profile, improving forecast accuracy and reducing imbalance costs.
• Remote reading removes the need for vehicle trips, cutting CO2 emissions.
• Technical and non-technical loss analysis becomes accurate and consistent, minimising losses and illegal use.
• Historical consumption is stored and available when needed.
• It provides the infrastructure needed to raise energy efficiency and lower energy costs.

MODBUS data transfer protocol

The common meeting point of all sensors, a symbol of stable and secure communication.

Modbus is to industrial devices what USB is to computers: a common connection interface.

It is a universal protocol, developed in 1979 by Modicon (today Schneider), that lets sensors, industrial PCs, data loggers and PLCs talk to each other and share data.

Many devices we use every day work smoothly in many countries because they meet certain standards.

Some of them:

• 220 V sockets and plugs that let devices draw mains power correctly

Speaking a common language simply makes more sense.

In today's technology age there are standards that make life easier without us even noticing.

Your phone, for example, connects to your home modem wirelessly as soon as you arrive, whatever the brand of phone or model of modem.

That is because the globally standardised Wi-Fi standard for compatible wireless connections has been adopted by every technology manufacturer.

Flash drives communicate over USB (Universal Serial Bus), and computers of any brand or model can read and write data over it. Plugging a device into a USB socket connects it without any further setup.

Every device designed to work with a computer is built to the USB standard, because every computer supports it.

In the same way, leading industrial device manufacturers build their PLCs with MODBUS, just as our computers and phones carry their own standards.

This turns the PLC and its software into a system that meets global standards, reaches Industry 4.0, works with almost every sensor type and transmits data without loss over a single communication channel.

Choosing digital measurement

Put simply, analogue and digital data transfer differ in capacity. Digital data gives higher-quality, more realistic results.

The best-known recent example is the leap in quality from analogue TV receivers to digital set-top boxes.

Hydrostatic level sensor

When a MODBUS-enabled sensor measures water level, it sends two parameters, pressure and temperature, to the management device without loss.

Analogue sensors transmit the value as an electric current, so cable length, temperature and humidity can distort the reading and cause errors.

Multi-parameter hydrostatic sensor

With MODBUS, continuous level and quality measurement reports three parameters: water level, water temperature and water quality.

This is not possible with analogue measurement.