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SAE J1939 Functional Safety Communications Protocol & Trailer Safety Assurance
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Commercial road and off-highway vehicles, as well as off-road construction machines, frequently utilize J1939-based application layers. In response to the growing need for functional safety, SAE has created specific protocols for CAN CC (classic) and CAN FD: J1939-76 and J1939-77, respectively.
An article on the CiA (CAN-in-Automation) website discusses the SAE standards for functionally safe communications on CAN CC (SAE document number 1-76) and CAN FD (SAE document number 1-77). SAE document number 1-76 describes the Safety Header Message (SHM) and Safety Data Message (SDM) pairing approach used to communicate safety-related data from a producing safety application to a consuming safety application. It also details the features of the original version, published in 2020, and lists the deficiencies of this version.
Finally, it describes the features of the updated version currently in development that address these shortcomings. In SAE J1939-77, the document explains how the space allocated for functional safety assurance information in the Multi-PG and FD Transport protocols is used to transmit safety-related data from a producing safety application to a consuming safety application. It also outlines three profiles currently being developed to meet various system needs while fulfilling functional safety requirements.
The IEC standard number 1 defines various communication errors that can occur. These errors include corruption, unintended repetition, incorrect sequence, loss, unaccepted delay, insertion, masquerade, and addressing. Additionally, the standard outlines safety measures that can be employed to detect these errors and achieve the desired level of functional safety. These measures include sequence numbers, time expectations, connection authentication, data integrity assurance, and redundancy with cross-checking.
The J1939-76 standard specifies two versions of functional safety support. This support applies to Parameter Groups (PGs) with parameter data payloads ranging from 1 to 8 bytes. Both versions use a Safety Data Group (SDG), which includes a Safety Header Message (SHM1 or SHM2) and a Safety Data Message (SDM), to transmit safety-related data from a producer to a consumer. The SDM, associated with an SHM, contains the safety-related parameter data used for a safety function.
The SAE J1939-77 standard provides three distinct profiles to support functional safety. Each profile is designed to meet different system requirements. These profiles use the Multi-PG and FD Transport protocols specified in J1939-22 for CAN FD. They can allocate a separate space in their messaging for cybersecurity and/or functional safety assurance information for a PG’s parameter data. This flexibility allows the standards to be customized to meet a wide range of system needs, from simple to complex, while meeting functional safety requirements. Read the article (PDF)...
SAE J1939 Starter Kit and Network Simulator
Our JCOM.J1939 Starter Kit and Network Simulator are designed to allow experienced engineers and beginners to experiment with SAE J1939 data communication without needing to connect to a real-world J1939 network, i.e., a diesel engine.
To establish a network, you need at least two nodes. This 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 consist of two J1939 nodes: our jCOM.J1939.USB, an SAE J1939 ECU Simulator Board with USB Port. More Information...
PCI Express Board Integrates 4 High-Speed CAN/CAN FD Ports
Kvaser has introduced their compact M.2 PCIe, a highly integrated embedded CAN Bus board that adds four high-speed CAN/CAN FD channels to any host computer with PCI Express connectivity and an available B or M keyed M.2 slot. The embedded board provides four distributed CAN CC (Classic CAN) or CAN FD transceivers, adding CAN CC and CAN [...]
ESP32: CAN Bus Programming with MCP2515 and MCP2517FD
For good reasons, the ESP32 processor is a prevalent choice for embedded hardware development. Besides considerable memory resources, it provides various hardware features for many applications, most prominently the Internet of Things (IoT). All that comes with more than reasonable price tags, specifically when you use one of the multiple ESP32 development modules. And since [...]
Kvaser's Leaf Supports Classical CAN, CAN FD in Silent Mode
Every professional CAN Bus development, may it be Classical CAN, CAN FD, or higher layer protocols such as SAE J1939, requires a data monitoring device for proof of functionality. Kvaser has introduced such a device, the Leaf v3 interface supporting Classical CAN and CAN FD in optional Silent Mode. The Leaf series depicts one of the straightforward [...]
Automotive Development Module has CAN FD, LIN, Ethernet Port
Renesas has launched a software development board featuring the R-Car S4 System-on-Chip (SoC). The scope of delivery includes the Whitebox SDK open-source software. The R-Car S4 facilitates the launch of Car Server/CoGW with high performance, high-speed networking, high security, and high functional safety levels required as E/E architectures grow into domains and zones. The R-Car S4 solution [...]
Industrial Strength Dual CAN FD Interface in Mini PCIe Form
The VL-MPEu-C1 module by Versalogic, compliant with the Mini PCIe format, is a tiny and rugged dual-channel CAN Bus add-on interface. It supports CAN-FD for high-speed data transfer but is still fully compatible with CAN 2.0 A and CAN 2.0 B (Classical CAN). It supports additional CAN functions, including message acceptance filtering, listen-only mode, and wake-up [...]
Programmable CAN Bus to USB, Bluetooth, BLE, WiFi Gateway
For the longest time, I had resisted the idea of creating my version of a CAN-to-USB gateway, primarily due to the vast competition. A professional CAN/J1939 development requires a professional CAN-to-PC solution to monitor data traffic. I am pleased with the PEAK PCAN-USB device, as shown in the above image. However, not everybody is willing [...]
PCIe Board with 4-Port Isolated CAN FD for Applications
Sunix (Taiwan) manufactures CAN (FD) interface cards for commercial, agricultural, military, government, recreational, and other industries. Their recently introduced CAN4F00SI PCIe card offers four isolated CAN FD ports. The interface cards can self-diagnose and repair data errors to meet the demand for accurate UAV (Unmanned Aerial Vehicle) control in mission-critical applications. The mission computers, autopilot computers, actuators, [...]
Mini PCI-E Module with Classical CAN, CAN FD, and GNSS
Antzer Tech, a subsidiary of Innodisk, introduced their GADN-FD7L0 PC interface card, which integrates CAN (CAN bus 2.0 a/b, OBDII, SAE J1939), CAN FD, and GNSS features into one mini PCI-E combo module. The board comes in a standard Mini PCI Express form factor. It supports USB 2.0 and two independent CAN FD ports with data-phase bit [...]
ECU and GPS Modules with CAN, CAN FD, SAE J1939 Connections
PEAK-System presented several innovative I/O products with Classical CAN and CAN FD connections in this year's Embedded World trade show. The versatile control unit PCAN-MicroMod FD ECU integrates customer-specific accessories for automotive applications. For this purpose, the device offers a CAN FD connection and a combination of analog and digital I/Os. The I/O processing and message [...]