Engine Monitoring Unit

Share engine information on the NMEA 2000® bus...


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Which devices can receive engine data from the EMU-1?

The EMU-1 is compatible with all certified NMEA 2000® devices that receive and display the NMEA 2000 PGNs that the EMU-1 outputs. Please cross-reference the EMU-1 NMEA 2000 PGN list (in the User Manual and in the Which NMEA 2000 PGNs are supported FAQ) with the receive PGN list of the NMEA 2000 monitoring device (e.g. MFD or chartplotter).

Any Raymarine SeaTalkNG or Simrad SimNet device that can receive and display the NMEA 2000 PGNs that the EMU-1 outputs will also be compatible, however a suitable network adapter cable will be required.

What are the power requirements of the EMU-1?

The EMU-1 can operate between 9 and 35 VDC and will typically use 25mA at 12 VDC.

If the engine gauges are to remain in-circuit, the EMU-1 must be powered from exactly the same power supply as the gauges otherwise the EMU-1 measurements will not being accurate. The EMU-1 gauge ground and the EMU-1 power ground must be common to prevent ground loops. Check that if the instrument gauge panel includes a reverse protection diode between the power supply and the actual gauge supply connection, the EMU-1 is correctly powered from the gauge supply connection.

What EMU-1 variants are available and what do I get in the box?

There is currently only one variant of the EMU-1. If you are interested in a special OEM variant, please contact Actisense Technical Support.

Part number EMU-1-BAS box contents:

1 x EMU-1 with pluggable screw terminals and NMEA 2000 connector dust cover

1 x Connector cover

4 x Connector cover retaining screws

4 x Mounting screws

1 x Actisense CD in sleeve (with documents and software)

1 x EMU-1 user manual

What are the connections on the EMU-1?

The EMU-1 has a standard M12 male, A-coded (Micro-C) connection to connect to the NMEA 2000 network and 16 screw terminal connections as follows:

- One "Power" input pair for powering the EMU-1

- Six "Gauge" inputs

- Four "Alarm" inputs

- Two "Tacho" input pairs

- Two "Auxiliary" inputs

What types of inputs does the EMU-1 have?

There are a total of 14 analogue inputs on the EMU-1.

There are six inputs labelled "Gauge". Each gauge input can be connected to either a resistive sender or the gauge connected to that sender.

There are four inputs labelled "Alarm". Each alarm input can be connected to either an alarm switch or the warning indicator connected to that alarm switch.
There are two inputs labelled "Tacho". Each tacho input can be connected to one of the following:

- an alternator terminal connection (usually labelled “W”, “R” or “AC”)

- an ignition coil connection

- an inductive Tacho sender

- a hall-effect Tacho sender

There are two inputs labelled "Aux". These inputs are not currently enabled and are reserved for future expansion of the EMU-1’s functionality.

What are the "Gauge" inputs for?

"Gauge" inputs are designed to be connected to existing (resistive type) engine senders, either with or without the engine gauge connected. In the case where no gauge is connected the EMU-1 automatically provides a current feed to the sender.

The EMU Configuration Tool allows the user to select the matching sender/gauge type from a defined list for each "Gauge" input. Ideally, please check regularly (once per month) that you have the latest version of the EMU Configuration Tool in order to have the latest supported gauge list.

If you have a gauge which is not supported, please contact Actisense Technical Support so your “new gauge” addition request a can be processed. The Actisense team will be updating the EMU Configuration Tool to support more gauge types based on customer feedback and requirements.

What are the "Alarm" inputs for?

"Alarm" inputs are designed to be connected to existing (voltage level) alarm type switches, (e.g. an over temperature switch). The EMU Configuration Tool allows the user to define the trigger voltage and trigger direction (positive: from LOW to HIGH or negative: HIGH to LOW) for each "Alarm" input. The user configures this as: Trigger the alarm if the input voltage goes "Above" or "Below" the set trigger level.

Please check that you have the latest version of the EMU Configuration Tool in order to have the latest supported alarm list.

What are the "Tacho" inputs for?

"Tacho" inputs are designed to be connected to existing Tacho signals from either the Alternator (“W”, ”R” or “AC”) terminal, an inductive Tach sender, an ignition coil or - a hall-effect Tacho sender. The EMU Configuration Tool allows the user to define "Ratio" or the number of "Pulses Per Revolution" that the selected Tacho signal will generate for each "Tacho" input. This ratio is usually referred to as the Pulses Per Revolution (PPR) and is normally supplied in the engine manual.

For an Alternator “W”, ”R” or “AC” terminal connection it can be calculated from:


For an inductive Tach sender it is derived from the number of teeth on the flywheel:

For an ignition coil it can normally be calculated from:

The engine manufacturer will usually supply this ratio so it should not need to be calculated.

The EMU-1 has the ability to automatically adjust to the input Tacho signal so the sender type does not need to be configured. However, currently only Alternator (“W”, ”R” or “AC”) and inductive Tach sender signals are sensed correctly by the EMU-1. If you wish to use an ignition coil signal with an EMU-1 please contact Actisense Technical Support. so your request a can be processed.

What gauges are compatible with the EMU-1?

Please refer to the What are the Gauge inputs for? FAQ for the full details.

The current supported gauge list as of EMU Configuration Tool v1.025 is:

Can the EMU-1 be connected in parallel to existing gauges?

The EMU-1 can be connected in parallel to existing gauges or as a replacement for some or all of the gauges. The EMU-1 automatically detects whether a gauge is present or not and configures itself to provide a current feed to the sender where required.

What engines is the EMU-1 compatible with?

Actisense is actively building up a database of what senders/gauges are to be found on which engines. However, that will take some time to compile as there are a large number of sender/gauge permutations even within a single engine model’s lifetime (as manufacturing methods change year on year). One of the primary inputs to this database is from EMU-1 customers and a future configuration option will make it easier for customers to send us the details of a working setup.

The current EMU-1 configuration requires the user to understand the specific manufacturer and type of each sender/gauge connected to the EMU-1 so they can select the matching option in the EMU Configuration Tool.

How many engines can a single EMU-1 support?

The EMU-1 now supports multiple engine instances and two engines can be monitored using a single EMU-1 provided the following conditions are met:

1. There are sufficient inputs i.e. using an EMU-1 for two engines implies that 3 gauge and 2 alarm inputs per engine are sufficient

2. The EMU-1 is powered from the same supply which powers the gauges; and the gauges for both engines share this same power supply or

3. If no gauges are used then the engines need to share a common ground

Otherwise a separate EMU-1 for each engine should be used.

How do I configure the EMU-1?

The EMU Configuration Tool is used to configure an EMU-1. An Actisense NGT-1 is also required as an NMEA 2000 PC Interface to allow configuring of the EMU-1 remotely over the NMEA 2000 network.

The tool itself is simple to use:

- The EMU-1 device to be configured is selected from a list of NMEA 2000 devices.

- The engine instance is specified for each "Gauge", "Alarm" and "Tacho" input.

- The input voltage monitor destination PGN field is specified (if required).

- The parameter / gauge type is specified for each active "Gauge" input.

- The alarm level and direction is specified for each active "Alarm" input.

- The tacho PPR ratio is specified for each active "Tacho" input.

- The configuration settings are sent to the EMU-1 by pressing “Send to EMU” button.

The EMU Configuration Tool User Manual details how to perform all of the configuration operations necessary to customise the EMU-1 to an individual installation. As the EMU Configuration Tool will be updated regularly, please ensure that the latest version is being used.

Can I request what I would like the EMU-1 to support?

The Actisense team are actively requesting customer feedback on future EMU-1 features and functionality. If you would like to make a request, please contact Actisense Technical Support. Your requests will be added to the EMU-1 ‘Wish List’ that is used to prioritise new features and functionality

Does the EMU-1 come with a cable harness?

The EMU-1-BAS is supplied without a cable harness. There are pluggable screw terminals on the unit that allow easy connection to the engine’s senders/gauges

What PGNs are supported?

The current supported PGN list as of EMU Configuration Tool v1.02 can be seen on the Specifications page

Why do I need an Actisense NGT-1 NMEA 2000 PC Interface on the network?

As the EMU Configuration Tool software program runs on a Windows PC it requires an interface to the NMEA 2000 network in order to configure and update the firmware of an EMU-1. This NMEA 2000 PC Interface is created by an Actisense NGT-1, making it a necessary requirement when installing or reconfiguring an EMU-1.

It is not necessary to keep the Actisense NGT-1connected to the NMEA 2000 network permanently; once the EMU-1 is configured it can be removed. However, having an Actisense NGT-1 always available to help diagnose issues with any NMEA 2000 device (from any manufacturer) will prove very helpful, and is a solid reason for keeping it on-board full-time.

What are the EMU-1 mounting options?

The EMU-1 comes complete with four stainless steel bulkhead mounting screws as the standard mounting method. Alternatively, the EMU-1 can be used with an optional DIN rail mounting kit: order part number DIN-KIT-1 which is suitable for use with top hat rail, type EN 50 022 or G section rail, type EN 50 035.

How do I update the firmware in my EMU-1?

Firstly, ensure that an Actisense NGT-1 (with firmware v2.210 or above) is connected to both your PC and the same NMEA 2000 network as the EMU-1 to be updated. Secondly, ensure that any other software program (such as NMEA Reader) has not opened the NGT-1’s COM port.

"ActiPatch" is the simple tool that downloads the latest EMU-1 firmware in to an EMU-1 device. Please note that the EMU-1 firmware version that a particular ActiPatch version can download is detailed on the website on the download link description. Run "ActiPatch" and select the NGT-1’s COM port from the "Comms" menu. The selected NGT-1 COM port will be remembered for all future sessions but it can be changed at any time if required. Select the EMU-1 to be updated from the "Device" drop-down list - it will appear as "Actisense Engine Gateway (SID xxxxx)", "Propulsion" (where xxxxx is the serial number of the EMU-1 device):

"ActiPatch" will open and read the latest EMU-1 firmware file and display its filename in the "ActiPatch" title bar. Click on the "Program" button to start the reprogramming process.

The blue "Power" LED on the EMU-1 should now be flashing faster (5 times per second) to indicate that the EMU-1 is in Bootloader mode. The "Tx" and "Rx" LED’s on the EMU-1 should be flashing very fast indicating the transfer of firmware information.

The message "Erasing has started..." will be displayed, the progress bar will move left to right indicating progress through this stage and the "Erase complete" message indicates the stage is complete. The "Writing has started…" stage will then start automatically, the progress bar will again indicate progress through this stage and the "Write complete" message will indicate stage completion. Finally the "CRC passed" and "Programming has completed successfully" messages will indicate that the device’s firmware has been successfully reprogramed/updated:

The EMU-1 will then reboot and run the new firmware. Close "ActiPatch" and open NMEA Reader to view the new firmware information on the "Network View" tab.

Can I connect an EMU-1 to Dual Station senders?

Yes, the EMU-1 is compatible with both single and dual station senders.

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.

What is the temperature range an EMU-1 gauge input can be used to measure?

This temperature range is dependent on what gauge is defined by EMU Configuration Tool for that input. An EMU-1 "Gauge" input set to measure "Temperature" is capable of measuring temperatures outside of the defined gauge range. For example, selecting a "40 to 120 degrees C" gauge can actually allow the EMU-1 to report temperatures all the way down to below 0 degrees C and above 140 degrees C. This is because the EMU-1 calibration curve for the sender/gauge has been extended beyond the gauge display range. However, the accuracy of the calibration curve outside of the normal gauge display range is usually compromised.

Is there any erratum for the user manual?

There was one error in issue 1.00 of the EMU-1 user manual. On page 12 the text should read:

Standard Grounded Sender with Gauge

“Figure 7 - Gauge Input Connection Examples” G4 Input:

Standard Grounded Sender without Gauge

“Figure 7 - Gauge Input Connection Examples” G3 Input:

What baud rate should my NGT-1 be set to?

The default NGT-1 baud rate of 115200 baud is ideal for use on an NMEA 2000 network with a peak bus load below 50%. NMEA Reader displays the current "NMEA 2000 Bus Load" to help the user understand if the peak bus load is above 50%, and if so allow the user to change the NGT-1 baud rate to 230400 baud rate.

Is the engine hour log stored in non-volatile memory?

Yes, from EMU-1 firmware v0.041 (and onwards) the Engine Operating hour log is stored in non-volatile memory and restored at the start of every session. Note that in EMU-1 firmware v0.022 (and below) the Engine Operating hour log would reset on a power cycle as it was not stored in non-volatile memory.

Can I custom configure the EMU-1?

The current version of the EMU Configuration Tool does not offer this as a feature.

In a future EMU Configuration Tool there will be an option to enter manual calibration readings for various gauges and senders. This requires a technician to take readings from the gauges using a multi-meter and then enter this corresponding data into the configuration program. This will allow for any analogue gauge to be catered for if the installer fills in the voltmeter readings vs. observed parameter on the existing gauge.

However, Actisense is actively analysing gauges and senders from all manufacturers to help create a comprehensive library of easy to select gauge options, with the end goal of making this manual configuration option unnecessary.

What parameters will the future Software or Configuration updates support?

Actisense welcomes any suggestions for new EMU-1 features and gauge compatibilities that will be added to the ‘wish list’. Current items on the EMU-1 ‘wish list’ are:

- Trim: PGN 127489

- Engine Parameters, Static: PGN 127498

What wire gauge should I use to connect my engine sensors?

The recommended wire to use between the gauge/sensor and the EMU-1 connectors will be a minimum of "24 AWG (0.5 mm diameter)".

end faq

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