Victron Changing NMEA2000 Instances on VE.CAN Devices

Key Takeaways

• NMEA 2000 instance conflicts are a common cause of incorrect data display from Victron VE.Can devices.
• The Victron GX device and Actisense NMEA Reader software with an NGT-1 interface are the primary tools for adjusting instances.
• Changing Battery and DC instances on a Skylla-i battery charger can interfere with GX device data readings.
• Always ensure unique instance assignments across your NMEA 2000 network to prevent data conflicts.

Why is my Victron VE.Can device not displaying NMEA 2000 data correctly?

Incorrect NMEA 2000 device or data instances are a common cause of data display issues with Victron VE.Can devices. You should first check the instance settings on your Victron VE.Can devices and any connected display units to ensure they are uniquely assigned.

Diagnosis

Follow these steps to diagnose NMEA 2000 instance conflicts on your Victron VE.Can network.

1. Check GX Device for Connected Devices:

• • Navigate to the GX device menu path: Settings -> Services -> VE.Can -> Devices.
  • Observe the list of connected VE.Can devices and their assigned NMEA 2000 device instances. Look for any devices showing duplicate instances.
  • What it means: If multiple devices have the same device instance, this can lead to data conflicts and incorrect readings on your NMEA 2000 display. The default NMEA 2000 device instance is 0.

2. Monitor Specific Device Behavior (Skylla-i Charger):

• • If you have a Skylla-i battery charger, observe if your GX device is unable to properly read data from it.
  • What it means: This symptom is commonly reported by installers and can be caused by changing the Battery and DC instances on the Skylla-i battery charger. The GX device expects specific instance assignments for proper data interpretation.

3. Check Fluid Level Display on Raymarine MFDs:

• • If you are experiencing issues with fluid level displays on Raymarine i70 or i70s units, verify the fluid instance and type settings.
  • What it means: Raymarine i70 and i70s displays support a maximum of 5 tank levels, with fluid instances ranging from 0-4, and the fluid type must be set to Fuel. Axiom MFDs (Lighthouse version 4.1.75) support a maximum of 16 tanks, with fluid instances from 0-15. Incorrect settings here will prevent tank data from displaying.

4. Verify Actisense NMEA Reader Behavior (Fluid Level Bug):

• • If you are using Actisense NMEA Reader to change fluid level instances and encounter unexpected behavior, be aware of a known bug.
  • What it means: Actisense software may interpret the fluid level instance as an 8-bit number, while the NMEA 2000 definition specifies it as a 4-bit number. This can lead to incorrect instance assignments.

Cause/fix table

Changing NMEA 2000 Instances

NMEA 2000 networks rely on unique identifiers, called instances, for each device and for specific data types. Conflicts in these instances can prevent data from being displayed correctly on your monitoring equipment. This section outlines how to adjust these settings for Victron VE.Can devices.

Understanding NMEA 2000 Instances

NMEA 2000 uses different types of instances:

• Device Instance: Identifies a specific physical device on the network. For Victron VE.Can devices, the NMEA 2000 device instance defaults to 0.
• Data Instance (or Fluid Instance, Battery Instance, DC Instance): Identifies a specific data source from a device, such as a particular battery bank or fluid tank. For Victron products, the Battery Instance and DC instance are typically the same. GX devices expect specific instance assignments for multi-output chargers: Charger's output one should be Battery & DC instance 0, output two should be Battery & DC instance 1, and output three should be Battery & DC instance 2.

Methods for Changing Instances

1. Using a Victron GX Device

The GX device provides a straightforward way to manage device instances for connected VE.Can products.

1. Access the GX device menu.
2. Navigate to Settings -> Services -> VE.Can -> Devices.
3. From this menu, you can select individual devices and adjust their NMEA 2000 device instance. Ensure each device has a unique instance number to avoid conflicts.

2. Using Actisense NMEA Reader Software with NGT-1

For more granular control, especially over data instances or when a GX device is not present, Actisense NMEA Reader software combined with an Actisense NGT-1 interface can be used. The Actisense NGT-1 is required for changing device and data instances using Actisense software.

To change a device instance:

1. Open Actisense NMEA Reader.
2. Select the network view.
3. Select the product you wish to configure.
4. Go to the properties tab and change the device instance.

To change a data instance:

1. Open Actisense NMEA Reader.
2. Select the data view.
3. Right-click on the PGN number corresponding to the data instance you want to change.
4. Modify the value.

Workaround for Actisense Fluid Level Instance Bug: A known bug exists where Actisense software may misinterpret the fluid level instance as an 8-bit number instead of the correct 4-bit number defined in NMEA 2000. To work around this:

1. Using your GX device, set the fluid type to Fuel (0).
2. Then, using Actisense NMEA Reader, change the fluid instance to your desired value.
3. Finally, using the GX device, set the fluid type back to your desired type.

3. Using GX Command Line (Advanced)

The GX command line can also be used to change Device- as well as data-instances. However, this method requires advanced Linux skills and is not recommended for users without experience in command-line interfaces.

Specific Instance Considerations

• Raymarine i70/i70s: These displays have a maximum number of tank levels of 5. For fluid data to display correctly, the fluid instance must be set between 0-4, and the fluid type must be Fuel.
• Axiom MFDs (Lighthouse version 4.1.75): These displays can connect a maximum of 16 tanks, with fluid instances ranging from 0-15.

Safety: Electrical and Network Precautions

Working with electrical systems and network cabling requires adherence to safety protocols.

• Always disconnect power from the NMEA 2000 network and any connected devices before making physical connections or disconnections.
• Use insulated tools when working with electrical terminals to prevent accidental short circuits. A short circuit across a battery bank can release hundreds of amps, causing severe damage or injury.
• Ensure all network cables are securely connected and properly terminated to maintain network integrity and prevent data loss or intermittent issues.

When to call a technician instead

While many NMEA 2000 instance issues can be resolved through DIY troubleshooting, there are situations where professional assistance is recommended:

• If you have followed all diagnostic and fix steps and the problem persists.
• If you are uncomfortable performing the steps involving software configuration or accessing device menus.
• If you lack the advanced Linux skills required for GX command line changes.
• If you suspect a hardware fault with an NMEA 2000 device or cabling.
• For complex network configurations or integration with multiple brands of marine electronics. Attempting repairs beyond your skill level could void product warranties or cause further damage to your system.