For water meter readings there are 2 main ways of doing so. You can either communicate from the water meter directly to the network such as LoRa or NB-IoT. Or you can use a device called a concentrator which collects the water meter data and then it does send the data further. Both ways of reading do have their advantages and disadvantages. Below we will go through some of them.
This is usually done with the LoRa water meter modules or in some cases with the water meter NB-IoT modules.
- No third party hardware needed
- Each water meter communicates on its own and if there is a fault, you don’t get the data only from one water meter
- Each water meter has to have a good signal to the LoRaWAN or NB-IoT network. If there is no signal, the data won’t be transmitted and you need to use the concentrator
- If there is an issue with the network which causes the water meters to stop transmitting due to the lost security context, you need to manipulate with each water meter
- Energy efficiency is worse compared to the WMBUS modules
- Usually, the LoRa or NB-IoT version is more expensive per hardware as well as per the connected device.
The water meters in this case have a WMBUS module, which is a long-time proved and very simple technology. The data from the water meter are being sent every 2 minutes and collected by the concentrator. The concentrator then communicates via LoRa, NB-IoT, or other networks (can be even local internet networks).
- Cheaper solution per water meter itself and cheaper for the operation - you pay only for 1 connected device
- Possibility to collect data from any WMBUS device – including heat cost allocators
- Possibility to collect data from already installed water meters and heat cost allocators
- The concentrator allows you to use the antenna with a bigger gain which helps in installations where there is bad network coverage
- You can choose between a battery-operated concentrator or an externally powered concentrator
- The concentrator is usually placed in a shared area of the house and if any manipulation is needed you don’t need to go into the apartment itself
- Both NB-IoT and LoRa versions are available
- If there is any fault with the concentrator, you don’t have data readings from 60 to 128 devices
- Extra hardware costs within each installation consisting of the price of the concentrator
Whilst each technology has its use-case where it should be used, the direct communication is suitable for smaller installations outside of the city, usually in a residential area consisting of family houses, where due to the low concentration of the water meter is not economical to use concentrator. Also, this usually requires changing the water meter itself. In apartment buildings, the use of a concentrator is preferred and allows you to retro-fit already installed water meters together with the heat allocator units – as long as they communicate via WMBUS.