The New Actisense Engine Monitoring Unit

The marine industry is renowned for its traditions and long established techniques for carrying out tasks, from simply tying an anchor hitch knot to the skill of judging varying wind and sea conditions. On the other hand the industry has also reacted to the encroaching digital age with ease, vast improvements and innovations have been made in all areas but especially within the marine electronics sector.

Although the marine industry is making considerable strides technologically, the recession came as a major blow to everyone from boat owner to manufacturer, both nationally and internationally. The effects of which are still evident today, however the green shoots of recovery are well within sight, commenting on the state of the marine industry, Phil Whitehurst, Managing Director of Active Research Limited said, “Although market conditions remain challenging, there is still a good demand seen by Actisense for essential navigation products. We have seen a small increase in business volume throughout the recession, and have begun to see some signs of recovery. Marine is no different to other discretionary spend markets, and I believe we are starting to see some clear recovery signs that should cause a solid uptick as pent up demand and loosening purse-strings release capital that consumers have been hanging onto as a safety net”.

When developing the EMU-1, the Actisense team had to consider many things; much research was carried out with regards to the wants and needs of vessel owners both in the commercial and leisure markets. Many vessels such as small motor boats, yachts and larger commercial vessels operate their on-board electronics using the National Marine Electronics (NMEA) 0183 standard. This standard, is a combined electrical and data specification for communication between marine electronic devices such as echo sounders, sonars and autopilots. To do this, the 0183 standard uses a simple ASCII serial communications protocol that defines how data is transmitted in a ‘sentence’ from one ‘talker’ to multiple ‘listeners’ at a time.

However, the demand for greater speed and the ability to share information across a greater volume of instruments led to the development of the newer NMEA 2000 standard which has been developed to supersede the NMEA 0183 serial data bus. The 2000 standard is able to connect various instruments along a single backbone, allowing one display unit to show many different types of information. The NMEA has included a higher data rate, a compact binary message format as opposed to the ACSII serial communications protocols plus the ability to support a disciplined multi talker, multi listener data network.



The introduction of the NMEA 2000 standard has made it easy for vessel owners to swap their old NMEA 0183 devices for the new and improved NMEA 2000 versions, however there are of course limitations to the amount you can realistically change, often these limits are down to overriding issues such as time and cost. Monitoring a vessels engine is a perfect example of this, many boat engines and generators output analogue data, especially in the leisure marine industry. As NMEA specialists, Actisense have developed a cost effective Engine Monitoring Unit (EMU-1), which creates an ‘analogue to NMEA 2000 gateway’, easily configurable and flexible enough to run alongside many engine makes and models.

The EMU-1 will convert engine parameters such as temperature, pressure tach and RPM into the corresponding NMEA 2000 engine PGNs. Taking advantage of the engines common ground for all its inputs, the unit can allow each to be a single signal wire. The unit is able to handle 6 gauge/ parameters inputs, 4 alarm inputs, 2 tach inputs and 2 additional auxiliary inputs. If an installation has two engines that share a common ground then a single EMU-1 can be used to convert both engines. Typically however, there will be only one unit per engine.

The EMU-1 has a PC based configuration tool that will allow the settings inside the EMU-1 to be changed to best suit the engine it is attached to. As the inputs are auto-ranging and capable of automatically calculating the resistance of any gauge left in-circuit, removing the need to manually measure and enter values into the devices, helping to streamline installation. Also helping to minimise time taken to install the unit, the customised case has been specially designed to allow easy access to the electrical signal input system while completely sealing the electronics. Andy Campbell, Chief Engineer commented ‘The EMU-1 has been designed with simplicity in mind. This will change the way analogue to NMEA data conversions are done. This product meets the rigorous demands of a marine environment and we are sure that it will become highly sought after in the trade’.

As with any NMEA 2000 device, plug and play is essential and the two part screw terminal system allows easy connection to the engine wiring harness. The unit can be used with one of the supported engine wiring harnesses, or with an installer created harness for other types of engines. Helpfully, the NMEA 2000 connector is mounted directly on to the customised case allowing the user to choose their desired drop cable length to reach the backbone, within 6 meters.

Although Actisense is a marine electronics brand and the Engine Monitoring Unit has been designed with the marine industry in mind, the applications for this product could well be applied to anything that carries a generator or analogue engine. An example of the brands product flexibility has previously been demonstrated in the automotive industry. In 2011, the Actisense buffer (NBF-2) was rolled out to a fleet of buses in New South Wales, Australia, improving and delivering real time passenger information through on-bus displays and street displays. The NBF-2 did this by providing amplified isolated data to six outputs, sending the GPS data to the e-ticketing units and control centre at the bus depot.

The design and development of the Engine Monitoring Unit has been carried out solely by the engineers at Active Research Ltd, with the design undergoing thorough beta tested by a renowned engine manufacturer. The unit will be manufactured and distributed from the Dorset based factory and will be available from January 2013. See here for more information on the Actisense EMU-1.