PLEXUS is Gent's ground-breaking new fire detection and alarm system that uses each wireless device as a transceiver. Lee Tuplin, product manager, Gent by Honeywell, explains how it works.
Gent by Honeywell is renowned throughout the fire industry for its innovative powered loop and the devices it drives. Indeed, the powered loop is the wired fire system market leader. With the introduction of PLEXUS, Gent is using this experience and innovation to extend the power of the loop into the wireless world.
PLEXUS is Gent’s ground-breaking hybrid wireless fire detection system, which gives an unparalleled level of integrity and user confidence. It is possible to use wireless devices where building constraints prohibit cables or disruption to the building, or if the activity within it needs to be kept to a minimum. In areas of buildings where cables can be run, wired devices can still be used.
Radio star
PLEXUS is unique as each wireless device in the network acts as a transceiver, creating a transmission path with a number of nearby devices to form a network of radio links. While in other hybrid wireless systems every device needs to link back to a single gateway, all of the devices in a PLEXUS system just need to talk to their neighbours. So the longest radio link is only ever from one device to the next one.
The system dynamically establishes radio links with a device and at least two other devices to ensure that the system continues to function, even if connection with a device is lost. This is a huge advantage if the use of an area changes, for example if a filing cabinet or new wall is built, which disrupt connectivity. The PLEXUS system will simply ensure that all devices can still communicate with others in the area to negate the obstacle. This has the key benefit of enabling the fire system installation to be driven by the building’s fire risk, not by its topology.
Each system can support up to 10 loop radio transceivers, which act as a gateway between the wired system and the wireless world. Each of these transceivers can manage a total of 31 wireless devices – so the versatile system is suited to large installations as well as small.
It uses 10 radio channels within the 868MHz frequency band, constantly hopping between them to minimise possible interference. It also monitors the links between devices to find the best path in the network. This ensures that changes to the building layout or use do not impact on the integrity of the Gent fire detection system.
Protecting the past and looking after the future
PLEXUS is ideal for use in heritage buildings – wireless can be used in areas that need to be treated with sympathy, yet later additions such as ducts, voids and roof spaces can be cabled.
Furthermore, wireless systems can offer fire protection where installing cables would be hazardous, such as ducts and voids contaminated by asbestos. This also has great applications in new build and temporary structures, where new systems can be setup quickly and moved to offer fire protection as the project takes shape.
PLEXUS wireless devices
Gent has drawn on its successful S-Quad multi-criteria sensors and devices to create a range of PLEXUS wireless devices that offer the performance and safety expected from Gent. All devices benefit from low voltage to support a wireless environment.
Devices in the range are powered by four lithium AA batteries configured as two power supplies to meet the requirements of BS 5839 part 1.
PLEXUS wireless sensor range
Just as with the wired S-Quad devices, the range of PLEXUS sensors can incorporate one or all of the following sensing elements:
- Dual optical
- Rate of rise heat
The unique dual angle technology employed in the sensor provides quick, intelligent fire decisions, enabling it to recognise and filter out potential false alarms due to steam or dust.
The PLEXUS wireless senor’s base mounts on to a ceiling using the S-Quad base to provide the wireless connectivity to the sensing devices. Additionally the base is tamper proof, yet can be easily removed from the ceiling for maintenance.
PLEXUS wireless audio visual devices
Based on Gent’s popular patented S-Cubed devices, the PLEXUS wireless audio and visual devices’ innovative system provides speech messages, sounder and strobe to meet the requirements of the Equality Act 2010 (formerly known as the Disability Discrimination Act)
PLEXUS wireless manual call points
The manual call point is resettable, tamper-proof and has an LED indicator to show operation.
Gent Vigilon control panel
The benefits of choosing a Gent Vigilon enjoyed today by thousands of building owners across the world can now be appreciated in the wireless environment.
By extending the power of the Vigilon loop, wireless devices use the same addressing and labelling structure as the wired loop devices, with the cause and effect, whether simple or complex, being common across the wired and wireless loops.
The PLEXUS system offers benefits to the system maintainer too – it offers battery life prediction – taking the guesswork out of battery replacement and enabling the maintainer to plan visits accordingly.
