CAN communication for DC insulation monitoring devices

CAN communication is widely used in DC insulation monitoring devices now. This article will introduce the CAN communication for DC insulation monitoring devices.

What is CAN Communication for DC insulation monitoring device?

CAN communication for DC insulation monitoring devices refer to the use of the Controller Area Network (CAN) protocol for the data exchange between the DC insulation monitor and other equipment in the system.

Benefits of using CAN communication for DC insulation monitoring devices

High reliability and Real-time Data

The CAN communication uses error detection and correction mechanisms to ensure reliable data transmission. CAN prioritizes messages based on importance, allowing for real-time transmission of critical data like insulation resistance measurements.

Multi-node communication

A CAN bus allows multiple devices to connect and communicate at the same time, and each node can send and receive data independently. This allows the DC insulation monitoring device to exchange data with multiple system components such as battery management systems, charge controllers, display units, etc.

Simplified wiring

The CAN communication adopts a twisted pair structure, which can significantly reduce the complexity and cost of wiring. This is very beneficial for insulation monitor integration and maintenance, especially in complex electrical systems.

How is CAN Communication typically used with DC insulation monitors?

Data protocol

The DC insulation monitoring systems commonly used CAN data protocols include CANopen and SAE J1939.

CANopen is a general CAN application layer protocol suitable for communication between various devices. The CANopen protocol defines concepts such as device configuration files, object dictionaries, and service data objects, and specifies message formats and data identifiers.

SAE J1939 is a CAN application layer protocol dedicated to commercial vehicles and agricultural machinery. The SAE J1939 protocol defines concepts such as device type, PGN (Parameter Group Number), CAN ID, etc., and stipulates message formats and data identifiers.

Message structure

CAN messages are the basic unit of CAN communication and are used to transfer data between devices. In DC insulation monitoring systems, CAN messages usually contain the following information:

Device ID: Identifies the device sending the message.

Insulation resistance value: DC side insulation resistance value measured by the insulation monitor.

Voltage measurement value: DC side voltage value measured by the insulation monitor.

Status flag: Indicates the status of the insulation monitor, such as normal, alarm, fault, etc.

Communication example

An insulation monitor might periodically transmit a CAN message containing the measured DC side insulation resistance. A central controller or monitoring system can receive this message and take appropriate actions based on the value (e.g., trigger an alarm if resistance falls below a threshold).

CAN Communication VS Modbus Communication in DC Insulation Monitoring devices?

For DC insulation monitoring, CAN communication shines in real-time critical data transfer with prioritization and multi-device support. Modbus, while simpler to implement and potentially cost-effective, is better for limited devices and may experience delays due to its polling nature. CAN requires additional protocol layers like CANopen for functionality, but offers robust error detection. Both can be cost-effective, with the choice depending on specific needs for real-time performance and scalability.

Feature	CAN	Modbus
Protocol Type	Multi-master, message-based	Master-slave, request-response based
Data prioritization	Supports message prioritization for critical data	No prioritization, all messages treated equally
Real-time performance	Well-suited for real-time data transmission	Can introduce delays due to polling nature
Multi-device support	Supports connecting many devices to a single bus	Limited number of devices per bus segment (typically 32)
Error detection	Built-in error detection and correction mechanisms	Relies on error checking within the application layer
Cost	Generally cost-effective due to mature technology	Can be cost-effective, but additional configuration might be needed
Complexity	Requires additional protocol implementation (CANopen, SAE J1939)	Relatively simpler to implement

Which Communication is used in Blue Jay insulation monitoring devices?

Blue Jay offers DC insulation monitoring devices with CAN Communication or RS485 communication. Our GYID series DC insulation monitoring device uses CAN communication, which is widely used for electrical vehicles. Our ZJS series, ZJJ series, and GYDCG series use RS485 communication, which is used for DC Systems, It systems, EV charger stations, etc.