Level measurement goes IoT

Veröffentlicht am: 08.04.2020

From Nilometer to an automatic alarm: The history of level-measurement

The measurement of water levels reaches far back in history. Already the ancient Egyptians measured the water level of the Nil by using multiple Nilometers and used the information for the cultivation of their fields.
In Europe level measurement had its beginning at running waters during the Middle Ages, as the preindustrial mills developed and a legal basis for water extraction became crucial.
While earlier in the day data had to be determined, recorded and forwarded by employees on site by hand, over the years more and more “automatic” systems took over. The manual detection of water levels by site remains a standard procedure for a long time and can still be met today on many measurement points.
Due to the increasing industrialization, the expansion of freight transport by water and the settlement of areas in potential flood areas, hydrological data acquisition became more and more important. In addition, groundwater measurement increasingly came to the fore. Not only to determine the groundwater reserves for drinking water production, but also, for example, to monitor the contaminated sites in landfills.

Up to date and reliable: requirements on modern level-measurement systems

While earlier attention was especially on early flood detection and warning, the drought years 2018/2019 showed a different extreme case. The transportation of goods on inland waters came mostly to an end. Also far-reaching ecological impacts, like fish mortality due to the lack of water and drinking water shortages in some communities, occurred. Of course the public and media interest increases during such times. In these times it’s extremely important to make reliable measured values available to the public.

Especially in times of climate change with its extreme weather conditions such as heavy rainfall and hot periods, a wellfunctioning alarm system can be a lifesaver.

It is therefore important to ensure that reliable and checked data are available to the responsible authorities and the public as fast as possible. This is already happening partly via WEB-platforms like “Hochwassernachrichtendienst” or “Mein Pegel”. Around 2500 water levels from all over Germany are currently running on the official water level- and flood app “Mein Pegel”.

The challenge is to update the measured values in a short time and to provide a high quality of the values shown.

This is what modern level systems look like today

Today hydrostatic probes with data logger and remote transmission modules are often in use. Amongst the hydrostatic probes we distinguish between systems with absolute and relative pressure measurement. Absolute pressure sensors always need a separate sensor in order to measure the barometric air pressure, which then gets subtracted arithmetically from the measured value of the level probe. When using relative pressure measurement, this barometric air pressure is fed into the measuring cell via a capillary in the cable. Many manufacturers protect this capillary from condensation by using desiccants. The disadvantage of these desiccants is the very high maintenance effort because they have to be replaced cyclically. ACS-Control-System deliberately goes a different way with its new level-measurement system. Thanks to a special air duct, this desiccant was already very successfully dispensed within the previous system. As a result, the maintenance effort and the costs per measuring point decrease significantly.

The most important thing is and remains accurate and reliable measured values. Many manufacturers are now striving to achieve this by using high-quality, sometimes capacitive, ceramic measuring cells. However, you are still dependent on a single measurement determination. According to the federal level manual, important levels have to be equipped with redundancy measurement. At slightly less important levels and groundwater measuring points, at least a cyclical measurement check is requested – for example via light plummet. What they all have in common, is the idea that the “primary” measured value is checked by another physical measuring system. In reality, this is often achieved by separately mounted radar or ultrasound measurements. Since these sensors are then usually spatially distant e.g. mounted on bridges or cantilevers, there are often differences between the measured values on the pressure and redundancy sensors, evoked e.g. due to traffic jams on the bridge or the influence of wind on the ultrasonic sensor.

ACS-CONTROL-SYSTEM has now taken up the advantages of automatic redundancy measurement and at the same time eliminated its current disadvantages. The result is a new, innovative measuring system that has already been registered for a patent.

In this system, the hydrostatic “primary sensor” and the redundancy measurement in form of a transit time measurement are integrated together in one measuring point. In this case, a pressure sensor is immersed in water as usual in a level pipe with a diameter of 2“ or more and a slim ultrasonic sensor is positioned above the expected maximum water level in the same pipe. During the measurement, the pressure sensor provides the primary value and after an adjustable cycle, e.g. once a day, a reference value is generated via the ultrasonic sensor. The evaluation electronics compare these two values. The user can pre-select a maximum difference between the two measured values, from which an alarm is then triggered. This provides a maximum of security of the measured values. Also it offers the advantage that if one sensor fails, measurements can continue with the reserve value of the second sensor. The immense savings potential due to the omission of frequent control plumbing on site should not be underestimated. However, one shouldn’t only consider the cost- and time savings. For example, control plumbing no longer has to be carried out in any weather on a snow-covered dam with the risk of slipping into the tearing water – which is a major plus in terms of occupational safety.

Another important point for self-sufficient measuring points is the power supply. Battery life should be as long as possible. Furthermore it is often difficult to equip the measuring points with PV modules because either there is too little light or the risk of vandalism is too high. ACS-CONTROL-SYSTEM has therefore designed its two data loggers with a remote transmission module with optimized power management. This allows the lithium batteries to last up to 10 years. In addition, the user also has the option of operating the modules with battery technology in conjunction with a PV module input, or, if possible, with a power supply unit.

Easily mounted and installed: The on-site operation

What is important is a simple and intuitive operation and commissioning of the measuring points on site. Gone are the days when users were ready to purchase special manufacturerspecific programming devices with special cables. ACS-CONTROL-SYSTEM relies on contactless, low-power Bluetooth® interfaces that can be addressed via existing tablets or smartphones. Because traditionally a great deal of attention is paid to the human-machine interface, the operating programs (app) are designed to be used mostly self-explanatory with no need of a complicated manual.

Data transmission – fit for the future

Not long ago, the 2G network in combination with csd data transmission was the predominant technology in the field of data transmission. Now the 2G networks will be switched off in the near future.

Many users have now installed outdated technology and it has to be quickly upgraded to modern standards. But this is where a huge problem arises. Terms like 5G network expansion or IoT (Internet of Things) are often propagated in the media, but the area-wide expansion of the 5G network will certainly take some time to be reality. Especially since the level measuring points are usually not installed in the metropolitan areas, but in remote areas where 5G will be expanded to last. In addition, it is almost impossible to find the right mobile contract for the best network coverage on site in the jungle of many providers and collective agreements. Therefore, ACS-CONTROL-SYSTEM is now breaking new ground. Futureproof mobile radio modules are installed in the devices, which can serve all networks from 2G to 4G and LTE. There is also preparation for 5G networks. The data transmission is based on an embedded SIM that independently uses the strongest mobile network and the strongest provider on site.

There are no additional costs for the user. All data traffic is either already integrated in the device price for several years, or it can be calculated separately cyclically using data or maintenance contracts.

The data transfer takes place according to the latest security standards such as Data encryption and VPN tunnels.

Secure measurement data management: a data cloud especially for level-measurement technology

With ACS portal, ACS-CONTROL-SYSTEM offers a data platform for managing all measuring points and data. Since this is not an off-the-shelf data cloud, it was possible to specifically address the concerns and needs of groundwater and level-measurement technology.

Via an authorized user access, the ACS portal offers access to the data and the measuring point management – from anywhere in the world without additional software installation. Thanks to a clear structure, the status of all measuring points can be seen at a glance. Measuring points with alarms or other “abnormalities” are marked immediately and can therefore be quickly located by the operator.

The positions of the individual measuring points can be shown via the map or satellite image view of Google Maps. This makes better route planning possible for preventive maintenance.

The parameterization or the necessary software updates of the devices on site can be carried out from the platform. This reduces the number of visits to the measuring points to an absolute minimum.

Other functions such as the graphic display of the measured values, data export and archiving of the data, as well as various reporting functions, completes the range of services.

More important than ever: reliable alarms

A very important, in some cases even life-saving, function, is the alarm management. In previous systems, alarming was mostly limited to SMS messages. ACS-CONTROL-SYSTEM goes a different, a more modern way. The classic SMS still exists, but it is supplemented by the option of transmitting alarms directly to the ACS app on the smartphone using a push message. There is also the option of a WhatsApp or email notification. By dividing the alarms into escalation levels, it is possible to run different alarm scenarios.

Everything from a single source: maintenance with predictable costs

The principle that a product is only as good as the service behind it is still up to date. With ACS-CONTROL-SYSTEM, support does not end with a free telephone hotline. We offer everything from a single source – from installation to complete monitoring of the measuring point. The customer can put together a package according to his needs from various maintenance options. The advantage is professional maintenance and repair of the devices in connection with a predictable cost framework while saving the customers personnel resources.

All information on the topic of IoT can be found clearly on our IoT page:

More on the subject of level-measurement

Reports about the flood disaster 2016 in Simbach:

Installation of the flood early warning system in Geretsham:

Press release on the flood of the century in 2013