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SAE J1939 Starter Kit And Network Simulator - Quick Start

Posted by Wilfried Voss on

jCOM.J1939 Starter Kit And Network Simulator

Our  jCOM.J1939 Starter Kit And Network Simulator is designed to allow the experienced engineer as well as the beginner experimenting with SAE J1939 data communication without the need of connecting to a real-world J1939 network, i.e., a diesel engine. To establish a network, you need at least two nodes, and that fact applies especially to the CAN Bus and SAE J1939 where the CAN controller will shut down after transmitting data without receiving a response. For that reason, our jCOM.J1939 Starter Kit And Network Simulator consists of two J1939 nodes, namely our jCOM.J1939.USB, an SAE J1939 ECU Simulator Board With USB Port.

A Quick Start Reference

The following is intended to provide a quick reference for the newcomer with the goal of a smooth start. 

First of all, it is important to notice that this starter kit is all you need to simulate an SAE J1939 vehicle network. No additional hardware is needed, but you can still connect the kit to any external network for monitoring and communication purposes. 

Also, please assure that both boards are connected to a Windows-PC per the provided USB cable. The USB port also acts as the power supply and the network will not be complete unless both nodes are working. As soon as power is applied, you should see LED2 (LED for USB Activity) blinking at a one-second frequency. This is the so-called heartbeat, indicating that the board is "alive."

In the Windows Device Manager, check the assigned COM ports:

The jCOM,J1939.USB device shows up as "Silicon Labs CP210x USB to UART Bridge," as shown in the above image. In this case, the boards show up as COM3 and COM13. These settings will most probably differ on your computer, but COM3 is the default port and one of the boards will claim it when available.

As a next step, start the  jCOMJ1939 Monitor softwarefor more information on download and installation, see:
https://copperhilltech.wiki/jcom1939-monitor-software/jcom1939-firmware-versions-and-update/

In this example, we assigned COM3 as the COM port for data transmission. Click on Start COM to initiate communication with the board.

We have also created a test file (SAEJ1939StarterKit-Test.jcom) that assigns a few sample PGNs for transmission. Please download the file and load it through the jCOMJ1939 Monitor software.

jCOMJ1939 Monitor Screen Shot - COM3

After loading the file, click ECU Simulation Mode, then click on Claim Address, and you should see a data flow immediately.

Now open a second instance of the jCOMJ1939 Monitor software and assign the second COM port (in our example, COM13). Again, click on Start COM to initiate communication with the board.

In the Filter section (see below) select Pass All, and you should see the same data stream.

jCOMJ1939 Monitor Screen Shot - COM13

Using this example, one node transmits SAE J1939 data, while the other receives it. However, you can even create examples where both nodes receive and transmit, and you can create message requests and their responses.

For more information see:


A Comprehensible Guide to J1939

a-comprehensible-guide-to-j1939-by-wilfried-voss.jpg

SAE J1939 has become the accepted industry standard and the vehicle network technology of choice for off-highway machines in applications such as construction, material handling, and forestry machines. J1939 is a higher-layer protocol based on Controller Area Network (CAN).

It provides serial data communications between microprocessor systems (also called Electronic Control Units - ECU) in any kind of heavy duty vehicles. The messages exchanged between these units can be data such as vehicle road speed, torque control message from the transmission to the engine, oil temperature, and many more.

The information in this book is based on two documents of the SAE J1939 Standards Collection: J1939/21 - Data Link Layer J1939/81 - Network Management A Comprehensible Guide to J1939 is the first work on J1939 besides the SAE J1939 standards collection.

It provides profound information on the J1939 message format and network management combined with a high level of readability.

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