Cisterns present plenty of challenges in level monitoring and control. But in the ocean of options on the market, how do you find the right device to monitor and control the water level of your cistern (or any other liquid)?
Table of contents
- What are common problems in cisterns?
- Which should you use, mechanical or electronic cistern level indicators?
- Which do you need, continuous level indication or point level detection in a cistern?
- Should you use a wireless level indicator in a cistern?
- Low-cost wireless level indicators
- Low-cost wired level point switches
- High-end level devices for advanced cistern applications
- The definitive guide to level monitoring and control in cisterns
Common problems in cistern level measurement
Okay, let’s make sure we’re on the same page. We define a cistern as a receptacle to store liquids, most often rainwater or well water. Cisterns have the capacity to store a few or thousands of liters of liquid. And yes, managing cisterns can offer challenges, but technology can improve your experience. So let’s begin.
First, how do you measure water level inside your cistern?
You must know this measurement to avoid overspills and know when to pump water out or in to keep a safe level. The market offers many types of level indicators, but should you buy a cheaper one or pay a little bit more? We get this question a lot, so this article will provide guidance to help you pick the right device based on the technical details.
Second, will the cistern have an automated system to pump water in and out, or will someone do that manually?
This question may not sound relevant, but some level indicators won’t work with automatic level control. Usually, wireless level indicators will only allow monitoring. Keep this in mind as you shop.
Which should you use, mechanical or electronic cistern level indicators?
You can find many examples of both mechanical and electronic level indicators, but what’s the difference between them?
Mechanical solutions such as float level switches generally cost less initially, but they can create problems later. Mechanical parts naturally wear down, and the sensor, always in contact with the liquid, can develop buildup. You also don’t have the option of monitoring this type of switch remotely.
Electronic level indicators have become more popular because of the benefits of their technology. These sensors don’t need contact with the cistern liquid, so you avoid the buildup problem. And remote level indicators can allow you to check your cistern level from your smartphone or laptop, even if you’ve left the plant.
On top of that, you can also control the pump, using an electronic level switch or a constant level indicator.
Which do you need, continuous level indication or point level detection in a cistern?
The answer to this question will depend on your setup. Let’s go over a couple of possibilities.
Say you have a cistern where you need to know its exact volume but don’t have an automatic pump system. In this scenario, continuous level indicators will work great for your application. Best of all, a wireless solution can send all the information to your phone or a remote display. Later in this article, we’ll review three examples of low-budget wireless level indicators and their pros and cons.
Although a continuous level indicator can send data and control the pump, this setup can be a little complicated.
Say you want a simple solution to control your cistern level. Here, level switches will help you the most. Many level switches can monitor both minimum and maximum levels, but you’ll still run into models where you need an individual switch for each. So check carefully before you buy.
Some switches have relay outputs as well, where you can turn the pump on and off. Later in this article, we’ll talk about a couple of level switches you can find on the market and how they might work for you.
Should you use a wireless level indicator in a cistern?
If you want to save money on installation, wireless solutions are mostly plug and play, but cable devices also offer simple installation. Low-cost wireless level indicators work well for single-point measurement and give you the data on your phone or on a remote display.
Installing wireless level indicators is easy, but they usually need batteries. Some devices offer up to 10 years of battery life, but that’s more an ideal lab configuration than a real-life application. Still, you can often extend your battery life by adjusting your configuration.
Cable devices need some sort of electrical power supply, and this setup may cost more, depending on the complexity of your installation. However, if you need to integrate it into a control system, you probably want to take this route.
Low-cost wireless level indicators
You know now that low-budget wireless level indicators work well for cistern level measurement. They have many good points, like simple installation and configuration and an adjustable measuring range.
For this article, we selected three strong options for level indication in cisterns:
This compact and flexible level indicator from E-Sensorix uses the ultrasonic working principle. The standard version has a sensor with an integrated antenna and wireless display to receive the level data remotely. If you need to install a remote antenna to get a better signal, you have this option as well.
The device can measure levels from half a meter to three meters in up to 19,999 liters and has a range of 150 meters between the sensor and the monitor. The sensor’s battery can last up to three years while measuring every 15 seconds, and the monitor needs power in the 150-to-240-volt range.
The EcoMeter P has three designs and different materials available, with a threaded connection for its standard installation. You can read a product review for more information.
Want to know more about Ecometer P, check out the Visaya Product Review
The Ecofrog is another ultrasonic level indicator, but it uses standard WiFi to communicate. It can measure from half a meter to three meters, and its battery can last up to 10 years – again, depending on its configuration
Speaking of configuration, you need to give the vendor all your pertinent details before you buy it, because the Ecofrog ships pre-configured. You’ll need a threaded connection to install it, too.
It can measure only liquids, but you can get all your data from a web app on your phone or laptop.
Want to know more about Ecofrog, check out the Visaya Product Review
Low-cost wired level point switches
Level switches provide a budget-friendly way to control level measurement. A single level switch can detect low and high levels, with a relay output to turn the pump on or off. You can also have an LED or siren to signal low and high levels.
The following switches give you two-point detection in each device.
Liquipoint T FTW31
The Liquipoint T FTW31 has the ability to detect up to five different points. It works in conductive liquids and has a measuring range from 0.1 to four meters. It also allows you to automate your level control.
You can control the level using its output to turn your pump on and off. It costs more than similar options but offers solid reliability for a long time.
Liquipoint T FTW32
The Liquipoint T FTW32 resembles the FTW31 but can measure from 0.25 to 15 meters. It can also control your process using a relay or any other output available and will detect the level of conductive liquids in up to five points.
As for installation, you shouldn’t have any problems setting it up in your cistern with thread connections.
High-end level devices for advanced cistern applications
If you want a highly accurate device with advanced diagnostics and easy integration and visualization, then you’ve come to the right place. These two devices provide good cost benefits, simple configuration, and high accuracy.
Prosonic T FMU30
The FMU30 is a straightforward ultrasonic level transmitter that varies in measuring range depending on its sensor. The 1½ -inch sensor can read liquids up to five meters and bulk materials up to two meters. If you need more than that, then the two-inch model measures up to eight meters in liquids and three and a half in bulk materials.
You can set up this analog loop-powered device using a local display or an external tool. The FMU30 also easily integrates into a control system, and if you need an external display you can use a universal like the RIA15.
The Micropilot FMR10 is a low-budget level transmitter with advanced technology for level measurement and communication. It uses the time-of-flight concept for its working principle and has a measuring range of eight meters.
This loop-powered device has a fairly simple installation. You can configure it using a tablet or smartphone through the SmartBlue App for iOS and Android.
It doesn’t have a display, but you can install that RIA15 we mentioned earlier or a similar universal display to indicate the level remotely. The operator can use the SmartBlue App to check the measurement as well.
The definitive guide to level monitoring and control in cisterns
To help you out, I prepared some slides with the main points of this article, plus some visual information to show you how to install and communicate with these devices and their pros and cons.
If you’d like to learn more about these devices and how to apply the best level indicator in your cistern, you can download the definitive guide to level monitoring and control in cisterns right here.
To know more about water levels in cisterns, you can get in touch with our engineers!