This post is a brief introduction to using the JCOM1939 Monitor Software. The purpose is to help you get started with the software as quickly and efficiently as possible. Please note that the application provides more features and information than mentioned here, and additional functions will be added in the future. For a comprehensive guide, please refer to the JCOM1939 Monitor User Manual.
JCOM1939 Monitor – Main Screen
When you run the Windows software for the first time, you need first to select the COM port that relates to the J1939 Gateway. In the Windows Device Manager, look for and select “Ports (COM & LPT).” If the driver was installed successfully, you will see “Silicon Labs CP210x USB to UART Bridge” followed by the COM port associated with it. This is the port you must select in the Windows software. Should the software not show that particular COM port, please try again after rebooting the computer.
It’s crucial that the simulator hardware is connected to a J1939 network. Without this connection, the simulator cannot send or monitor any data, emphasizing the importance of this step.
The jCOM1939 Monitor software for Windows contains three main areas:
- At the top, you have the COM port section, where you can select the port number associated with your USB port. By clicking on Start COM, you initiate the connection to the J1939 gateway. When the connection is made, you will see the Heartbeat bar changing in a one-second interval. If the heartbeat does not change, please check that you have selected the correct COM port number and have a connection with the gateway. If this doesn’t help, try rebooting your computer.
- The next section is divided into several tabs, such as ECU Setup, Filter, Transmit, Network, and Gateway. The following chapters explain these tabs.
- The bottom section shows the SAE J1939 data as it is received or transmitted through the gateway.
In general, you can save the complete current setup to a file or load an existing one using the File menu items.
JCOM1939 Monitor – Data Display
As you can gather from the top image, the program lists all received PGNs according to the PGN filter settings. The displayed information includes:
- PGN Counter
- PGN
- Source Address – SA
- Destination Address – DA
- Priority
- Message Length
- Data
- Description (assigned in PGN filter settings as described below)
Special Case: Transport Protocol (TP)
Please be aware that the displayed priority will be 255 when a data frame of more than 8 bytes is received (TP – Transport Protocol). The Transport Protocol uses a Priority = 7 but does not transmit the priority of the original message.
JCOM1939 Monitor – ECU Setup
If you intend to monitor SAE J1939 data traffic, you don’t need to do anything here. But if you want to transmit PGNs, you need to set up the ECU parameters.
In this section, you configure an SAE J1939 ECU through parameters such as Preferred Node Address, Negotiable Address Range, and the NAME setup. If you are unsure how to set the parameters, go with the default ones. They are set up to have the ECU operate on the safe side without interfering with your J1939 network. Remember to click on the Claim Address command button before proceeding.
JCOM1939 Monitor – Filter Messages
The Filter section lets you filter any PGNs (Parameter Group Numbers) from your network. Enter the PGN of your choice and a description (optional), then hit the Save command button. The PGN provided is part of your J1939 data traffic, which will show on the data screen below. If you are unsure which PGN to filter, click on the Pass All option. This will give you an overview of all PGNs in the network, and you can choose which one to filter.
To modify a specific PGN, click on it in the table. All parameters will appear in the editing section. Modify the parameters to your liking, then hit Save again.
JCOM1939 Monitor – Transmit Messages
Please be aware that you can only transmit messages when you have chosen ECU Simulation Mode in the ECU Setup tab. Otherwise, the software will indicate that no node ID is available. You can design messages by entering the PGN, Destination Address (255 = Global Address = Broadcasting), Priority, Data, Transmit Interval (optional), and Description (optional).
Transferring the PGN into the Transmit table is a simple process. Just click the Save command button. If you have entered a transmission frequency, the PGN will appear in the Receive window below. For a single (manual) transmission, leave the Interval at zero, select the PGN in the table, and click on the Transmit command button.
To modify a specific PGN, click on it in the table. All parameters will appear in the editing section. Modify the parameters to your liking, then hit Save again.
Transmitting PGNs Using a Frequency
To transmit a PGN using a frequency, first select the appropriate option in the “Transmission Rate” list box. Then, enter the desired frequency in milliseconds and click on the “Save” button. The program will automatically send the PGN at the set frequency.
SAE J1939 Starter Kit and Network Simulator
Our JCOM.J1939 Starter Kit and Network Simulator is designed to allow the experienced engineer and the beginner to experiment with SAE J1939 data communication without the need to connect to a real-world J1939 network, i.e., a diesel engine. To establish a network, you need at least two nodes. That fact applies especially to CAN/J1939, where the CAN controller will shut down after transmitting data without receiving a response. Therefore, 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.
The jCOM.J1939.USB gateway board is a high-performance, low-latency vehicle network adapter for SAE J1939 applications. The board supports the full SAE J1939 protocol according to J1939/81 Network Management (Address Claiming) and J1939/21 Transport Protocol (TP). More Information…