Victron VE.CAN NMEA2000 Instances: Changing Device and Data Settings

Key Takeaways

• NMEA 2000 instances help identify multiple similar products on a network, preventing data conflicts.
• Victron products default to NMEA 2000 device instance 0, which may need adjustment in complex systems.
• GX devices can change device instances, but Actisense software with an NGT-1 USB is required for data instances.
• Changing data instances on some products, like Skylla-i chargers, can prevent GX devices from reading data correctly.

What are NMEA 2000 Instances and Why Change Them?

NMEA 2000 instances are identifiers used to distinguish between multiple similar devices or data sources on the same network. For example, if you have two battery monitors or two fuel tanks, each needs a unique instance number so that your Multi-Function Display (MFD) or other NMEA 2000 devices can correctly identify and display data from each source.

The NMEA 2000 standard uses two main types of instances: the Device instance and the Data instance. The Data instance can be referred to by different names, such as Fluid instance, Battery instance, or DC instance, depending on the type of data it represents.

Victron products, by default, set their NMEA 2000 device instance to 0. This is also the default for the VE.Can device instance. While this default works for simple systems, you may need to change instances to resolve conflicts or customize how data appears on your MFD. For example, Raymarine i70 and i70s displays support a maximum of 5 tank levels, with fluid instances ranging from 0-4. Axiom MFDs, running Lighthouse version 4.1.75, can connect to a maximum of 16 tanks, supporting fluid instances from 0-15.

How to Change NMEA 2000 Instances

Changing NMEA 2000 instances on your Victron VE.Can network depends on whether you need to adjust a device instance or a data instance, and which tools you have available.

Changing Device Instances

Device instances identify the physical Victron product on the network.

1. Using a GX Device:

• • Navigate to the "Settings" menu on your GX device.
  • Select "Services".
  • Choose "VE.Can".
  • Select "Devices".
  • This menu shows a list of all devices on the N2K / VE.Can network. You can change the device instance for each listed product here.
  • Note that some products, such as Lynx Smart BMS, Solar chargers with a VE.Can port, and Battery chargers with a VE.Can port, have functionality that relates to the device instance.

2. Using Actisense Software with NGT-1 USB:

• • Ensure you have the Actisense NGT-1 USB interface connected to your computer and the NMEA 2000 network.
  • Open Actisense NMEA Reader software.
  • Select the network view tab, located at the bottom left of the interface.
  • Select the specific product whose device instance you wish to modify.
  • Go to the properties tab, at the bottom right, and change the device instance value.

Changing Data Instances (Fluid, Battery, DC)

Data instances identify specific data streams from a device, such as a battery's voltage or a tank's fluid level.

1. Using Actisense Software with NGT-1 USB:

• • This is the recommended method for changing data instances.
  • Ensure you have the Actisense NGT-1 USB interface connected.
  • Open Actisense NMEA Reader software.
  • Select the data view tab, located at the bottom left.
  • Right-click on the PGN (Parameter Group Number) for which you want to change the data instance. This option is only available for PGNs that allow data instance modification.
  • Change the value as needed.

2. Command Line of a GX Device:

• • This method allows changing both device and data instances.
  • It requires advanced Linux skills and is primarily for experienced software developers. Victron advises caution if you are not familiar with Linux command-line operations.

Important Considerations for Data Instances:

• Battery and DC Instances: Within Victron products, the Battery Instance and the DC Instance are the same value. Changing one will automatically change the other.
• BMV Preconfiguration: The Victron BMV (Battery Monitor) sends out two voltages: the main voltage and the auxiliary or starter voltage. It comes preconfigured with two battery instances: 0 and 1, to differentiate these.
• Skylla-i Battery Chargers: While it is possible to change the Battery and DC instances on a Skylla-i battery charger, doing so will prevent a GX device from properly reading the data. The GX device expects the charger's output one to be on Battery & DC instance 0, output two on Battery & DC instance 1, and output three on Battery & DC instance 2.
• Actisense Fluid Level Instance Bug: There is a known bug when changing the fluid level instance using Actisense software. This is likely due to Actisense interpreting it as an 8-bit number, while the NMEA 2000 definition specifies it as a 4-bit number.
• • Workaround: To address this, first use your GX device to set the fluid type to Fuel (0). Then, use Actisense to change the fluid instance to your desired value. Finally, use your GX device to set the fluid type back to its original setting.

Tools Not Recommended by Victron

Victron advises against using Maretron software for changing NMEA 2000 instances. They state that they do not understand how Maretron's N2KAnalyzer software works with its "Unique Instance" terminology, which automatically determines if a device uses device or data instances. For reliable instance management, especially for data instances, Victron recommends using Actisense.

Cause/fix table section

Safety: NMEA 2000 Network Handling

Working with NMEA 2000 networks typically involves low voltage DC power. However, always ensure power is disconnected from the network backbone before making physical connections or disconnections to prevent accidental shorts or damage to equipment. Use appropriate tools and follow manufacturer guidelines for all installations.

When to call a technician instead

While changing NMEA 2000 instances is often a straightforward configuration task, you should call a qualified technician if:

• You are uncomfortable working with marine electronics or network configurations.
• You encounter persistent data conflicts or display issues after attempting instance changes.
• You need to change instances via the GX device command line and do not possess advanced Linux skills.
• You suspect a hardware fault with your NMEA 2000 backbone or connected devices.
• Your system is under warranty, and you are concerned that DIY changes might void it (though instance changes are generally considered configuration).