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The EMU-1 Engine Monitoring Unit is a powerful gateway to help convert analogue signals from your engine into NMEA 2000 data, making that information more widely shareable and therefore more valuable.
One of EMU-1’s biggest advantages is that it has been designed to be engine brand agnostic. What matters more is which gauge/sender is being connected. Actisense offers an extensive preconfigured gauge library and a Custom Gauge Manager which allows for just about any gauge to be configured manually for digitisation.
The below guide has been designed to help you understand how to configure gauge inputs, alarm inputs and Tacho inputs, to get the most out of your EMU-1.
To configure your EMU-1, you will require an Actisense NMEA 2000 PC interface such as an NGT-1 or NGX-1. You will also need to download our free Actisense Toolkit software. This article explores how the EMU-1 should be configured using the NGX-1.Learn more about EMU-1
There are six Gauge inputs which are designed to be connected to existing engine senders (resistive type) either with or without the gauge connected. In the case where no gauge is connected the EMU-1 automatically provides a feed to the sender. A dual station sender must always have two gauges connected to it: the EMU-1 cannot replace one or both of those gauges. If it is required to remove one or both gauges, the dual station sender will need to be replaced with a single station sender.
Insulated Terminal Sender with Gauge (G1 Input):
Insulated Terminal Sender without Gauge (G2 Input):
Standard Grounded Sender without Gauge (G3 Input):
Standard Grounded Sender with Gauge (G4 Input):
There are four Alarm inputs which are designed to be connected to existing alarm type switches. The EMU-1 can be used with or without the alarm indicator (e.g. lamp or buzzer) connected. If there is no alarm indicator, a suitable resistor can be used in its place.
For 12 V supplies it is recommended to use a 1 kΩ, ¼ W resistor, for 24 V supplies it is recommended to use a 1 kΩ, 1 W resistor. Some alarm switches are incorporated into their relevant sender and are also suitable to connect to the EMU-1.
There are several different combinations of switch type and wiring method that the EMU-1 Alarm inputs are compatible with.
Supported Switch and Installation Types
Critical Circuit Requirements
There are two Tacho inputs which are designed to be connected to existing engine senders either with or without the gauge connected. The Tacho inputs must be calibrated in the configuration tool. The Pulses per Revolution (PPR) must be entered to allow the correct RPM to be calculated by the EMU-1.
There are several different sender options that can be used to generate NMEA 2000 RPM data. Each supported type is listed below along with the information required to configure the input using the configuration tool.
Hall Effect and Electronic Pulse Senders
The EMU-1 configuration tool allows the “ratio” to be configured. This ratio is usually referred to as the PPR (Pulses Per Revolution). The engine manufacturer will usually be able to supply this ratio so it should not need to be calculated.
For an Alternator (“W”. “R” or “AC”) terminal connection it can be calculated from:
PPR = (Crank pulley diameter / Alternator pulley diameter) × (No.of poles in Alternator / 2)
For an inductive sender it is derived from the number of teeth on the flywheel:
PPR = No.of teeth on flywheel
For an ignition coil it can normally be calculated from
PPR = (No.of cylinders × 2) / (No.of strokes × No.of ignition coils)