NMEA 2000 CANomaly

Essential NMEA 2000 Electrical Diagnostics Monitoring for Your Vessel.

Detects Silent and Violent NMEA 2000 CAN bus failures.

NMEA 2000 CANomaly is a device that can be permanently installed within a NMEA 2000 network and detect problems.  This device continually monitors the NMEA 2000 network signals Net-H (CAN_H), Net-L (CAN_L) and Net-S (supply voltage), and alerts if any issues are found.

Applications include:

• Fault detection – such as CAN Wiring faults, CAN PCB faults, CAN Connector faults

• Wiring aging – trends of CAN voltages can be measured and if looked at over a longer period of time since installation. Trends may indicate degradation.

Features:

NMEA 2000 Alerts:

  • CAN_H, CAN_L and differential voltage measurement on a per device basis
  • Net-S – 12v supply voltage monitoring
  • CAN error frame diagnostics
  • Recording over longer term to analyse longer term trends (using SD-card)

Data supported and transmitted over NMEA 2000:

• All mandatory NMEA 2000 PGNs

• Proprietary Voltage Diagnostic – Offending Device Src Add, Fault Type

Data supported and transmitted over NMEA 2000:

  • All mandatory NMEA 2000 PGNs
  • Proprietary Voltage Diagnostic – Offending Device Src Add, Fault Type

 

Raises NMEA 2000 Alerts ⚠️

  • Net_S – 12-volt supply voltage too low or too high
  • Net_L (CAN_L) short circuited to ground
  • NMEA 2000 CAN bus over-termination
  • CAN bus total failure
  • Wiring harness faults (error frame existence)
  • Aging and anomaly detection

 

LEDs

  • CAN receive
  • Error detected

 

Oscilloscope Mode

The device can get an example CAN oscilloscope trace for any NMEA 2000 device on the network (CAN_H, CAN_L and differential).  An example is shown in the screenshot available from the application below.

CAN Scope Trace

Availability:

 

•           Windows application for displaying CAN ID or source address-based data

Full NMEA 2000 device in ECU casing and NMEA 2000 connector ready for white labelling.
PCB ready for integration into customer device via serial connection

Full NMEA 2000 device in ECU casing and NMEA 2000 connector ready for white labelling.

PCB ready for integration into customer device via serial connection

A PC application is also available e.g.:

CAN Oscilloscope Mode

CAN Scope Trace

CAN Voltage Diagnostics

CAN Voltage Diagnostics

e.g. warning that one of the devices having a differential voltage < 2 volts.

Failure Examples

As an example of a silent failure, a CAN_L shorted to ground issues is compared below.  A healthy CAN frame is shown on the left and the fault CAN frame is shown on the right.  NMEA 2000 CAN communications will continue successfully even in the event of this failure due to the fact that there is still a differential signal.  This is one of the strengths of CAN technology.  However, this failure is an indication of an issue that will eventually lead to a total failure.

This is the kind of issue that can be caused by a lightning strike, NMEA 2000 cable wear and tear or NMEA 2000 device PCB failure.

Healthy CAN Frame

CAN_L shorted to ground