Mains Borne Signalling (MBS) has been used since the 1980s for sending and receiving digital data between pieces of electronic apparatus.

Equipment connected to the electrical circuit in a building places a tiny additional voltage on the Earth and Neutral wiring. High frequency tones are transmitted along the wires, like two musical notes, but at very much higher frequencies. A receiver on the circuit detects these tones and decodes them into the “ones” and “zeros” that make up digital communication.

The primary advantage of Mains Borne Signalling is that it negates the need to weave standard ethernet or, dedicated cabling throughout a building’s infrastructure, eliminating the disruption, mess and additional cost that entails.

Prefect Controls were early adopters of MBS and use this technology to connect thousands of room nodes on their Irus product – a heating control system developed specifically for student accommodation.

Will Dean is the Systems Engineer at Prefect, “MBS has come a long way since the early days when interference and drop-outs could cause issues with products ‘talking’ to each other. But we’ve developed solutions for every problem we’ve encountered, to a point where communication is now very stable and reliable.”

Prefect have enhanced the performance of their system with the addition of sophisticated error-correction technology.  This ensures data is reliably and accurately transferred from point-to-point.  Error correction involves mathematically manipulating data so that even if some of it is lost or damaged during transmission, the receiver will be able to ‘fill in the blanks’ and still understand the message.

Irus measures and monitors temperature, humidity, light and decibel levels. The data it collects via the room node is transmitted to the central controller which in turn is connected to the internet. Energy and Accommodation Managers view and adjust settings in individual rooms and run reports – all from the web-based portal.

Will Mills is a Project Manager at Prefect and recently installed Irus at UWE in Bristol, he explains, “Universities prefer installations to be carried out in the summer holidays when there are fewer students around and access to rooms is easier. Mains borne signalling speeds up the whole installation process. This summer we had 6 weeks to fit 2000 rooms at UWE in Bristol, that just wouldn’t have been possible if we’d needed to lay cabling throughout each of the 24 blocks we were working in.”

Prefect has developed practices, products and protocols to ensure their system works at any location, whatever the configuration of the buildings on the site or the wiring and network systems they encounter.

Will Dean continues, “There are points in a network where the neutral and earth wires are bonded together, blocking the signal. This generally happens where a supply enters a site, in these circumstances we use dedicated cabling or the existing Ethernet network to link separate blocks of the site, while still using MBS within each block.

In larger buildings, it may be necessary to connect different sections of the building with wired signalling rather than MBS, but we can work with all correctly wired circuits. Sometimes the installation of Irus reveals pre-existing faults with the wiring, particularly earthing problems. A site survey at the beginning of a project helps our engineers to specify the mix of MBS and wired signalling to give reliable communication and detect any faults that need rectifying.”

In the challenging environment of student accommodation Prefect prioritise robustness and reliability over super-fast theoretical performance as found in domestic ‘network extender’ products. More than 20 years’ experience of ‘making’ electrical circuits work with their products has seen Prefect become expert in the minutiae of Mains Borne Signalling.