1) Use Ethereal (available at www.ethereal.com) for network trouble-shooting and as an excellent learning tool!
If you want to really know what’s going on under the bonnet, you need a network analyser. Ethereal is one of the most diverse, useful and accessible packages available and is completely free of charge. Download it now and start to understand what’s really happening in your network.
2) Fibre optic installation companies may terminate fibre into a patch box that has dissimilar connectors to the type of Ethernet switch that you want to use. This need not be a problem as the connectors are solely for making a physical connection and in no way affect the optical signal (apart from slight attenuation). Simply purchase a fibre-optic ‘patch lead’ with the appropriate connectors at each end and connect the termination box to the switch. Fibre patch-leads are readily available in varying lengths and with a wide range of different connectors. Common fibre-optic connectors include SC, ST, MTRJ and LC.
3) It is possible to Extend Ethernet connections over a single twisted pair of doorbell grade wire, an old piece of previously installed RG59 co-axial cable or across copper previously used for RS485 communications. It is often possible to use existing cabling in conjunction with a variety of Ethernet converters to save the cost of installing long runs of brand new cable. Find out what cable is available for use on site, then speak to Amplicon!
4) If a site-wide network already exists, the most cost-effective BMS solution is to piggy-back your system onto this network. However, the local IT department will rarely allow unrestricted access to their precious commodity.
During negotiations, consider asking the IT department to implement a VLAN* (Virtual LAN) as a compromise. A virtual LAN allows you to add your equipment to existing network points (as advised by the IT department) without any possibility of your data interfering with existing network traffic and vice-versa.
Alternatively, there may already be dark fibre (fibre-optic cores not yet in use) across site onto which you can add your own Industrial Ethernet switches to build a reliable Ethernet based BMS system.
5) A pair of wireless serial to Ethernet converters can be used to extend runs of RS485 through areas where installation of cable is not possible or is cost-prohibitive. An entire multi-drop bus can be created with as many or as few wireless segments as required.
6) Power over Ethernet is a rapidly emerging technology that can provide up to 13W of power over the same Cat 5 or Cat 6 cable as is used to transmit Ethernet data. The fist door access controllers that directly support PoE are emerging on the market and more BMS equipment can be expected to follow. An innovative way to use PoE with non-PoE devices is by means of a ‘splitter’* that can split the power and data connection providing a normal Ethernet connection and 24Vdc power at up to 500mA. This solution means that a separate power cable need not be run to Ethernet devices.