In principle, the higher the LEN, the higher the voltage drop, and typically higher LEN devices are placed closer to the power insertion point on the network, to minimize cable length, which in turn reduces voltage drop.
Devices such as MFDs are commonly run from their own power supply, due to their high power nature. This is important, as any device which is over 20 LEN (1A), should not be powered from the NMEA 2000 network, and requires its own independent power supply. You need this value to perform voltage drop calculations, as this is done using Ohms Law.ġ LEN is 50mA, thus 20 LEN is 1A. LEN is a way of representing how much current a device draws from the network, and every certified NMEA 2000 device has a LEN, which should be published by the manufacturer in the device documentation. Understanding Load Equivalency Numbers (LEN) The diagram doesn’t need to be too scale, or precise and a hand-drawn diagram will be sufficient, however, the diagram is necessary to do any voltage drop calculations when considering power implementation.Īt a minimum, the diagram must include cable lengths, power insertion location(s), LEN (Load Equivalency Numbers) of each device, and the single shield wire location that is connected to the Vessel’s RF Ground. So, how do you power your NMEA network? The first and arguably most important thing is a network diagram, which details all cables, connectors, and devices that will be on the network. Whilst this article can’t cover everything it will cover some of the fundamentals.
Box Dimensions: 3"H x 6"W x 10"L WT: 0.Powering your NMEA 2000 network shouldn’t be a chore or a difficult task, but there are various things to consider during the planning stage, which will save you a lot of time when it comes to doing the installation.
Actisense welcomes enquiries from software manufacturers who would like to incorporate NMEA 2000 and the NGT-1 into their software. With the upcoming 'Third Party Gateway' status, leading chart plotter software will be able to be certified to work with the NGT-1. The supporting Actisense Software Development Kit (SDK) helps to reduce the required development time. The firewall feature enforces the NMEA 2000 bus rules, so software manufacturers can create compliant software at a fraction of the direct certification costs. The diagnostic NMEA Reader software allows viewing of NMEA 2000 messages with configuration options, enabling the set-up of all Actisense products on the NMEA 2000 bus. The Actisense NGT-1 is the only intelligent NMEA 2000 gateway available to precisely transfer messages to and from the NMEA 2000 bus. NGT-1-USB is the standard option - USB interface for bi-directional connection to a PC. NMEA 2000® to PC Interface Interface your PC to the NMEA 2000 bus with a functional firewall gateway.