Tough nuts to crack: The Kübler SAE J1939 solution for commercial vehicles

Although from the outside they look like big bruisers, they are really high-tech products on wheels: construction and agricultural machines or trucks and buses. Thanks to electronic control units their regulations and safety applications have become ever more complex. The high quality demands found in the sector result not least from the harsh environments encountered – whilst at the same time the piece quantities involved are very small and the variety enormous.

In short: Kübler has answered the demands of the industry for communication systems suitable for their applications by implementing the standard protocol of the Society of Automotive Engineers SAE J1939 for commercial vehicles and ships, railway vehicles, construction and agricultural machinery. This has been achieved primarily on the basis of CAN and by networking system components on a standardized basis, whilst at the same time offering manageable costs, flexible communication options and compatible components.

SAE J1939 was integrated in the proven Kübler magnetic absolute CAN encoder types M3658/78 and M3678 and ensures a smooth-running exchange of information between individual sub-systems – whether it is a matter of current rotational speeds in construction machinery or of idling speed under load for lifting platforms.

The Kübler Sendix encoders with the SAE J1939 interface and 14-bit resolution support virtually all common requirements of the special protocol and make an essential contribution to the overall system diagnostics or to the quick localization of failures. In accordance with the protected Kübler Safety-Lock plus technology, the encoders boast especially sturdy bearing assemblies with interlocked bearings. Furthermore the Sensor-Protect technology with its fully encapsulated electronics and separate mechanical bearing assembly ensures the very high protection rating IP69K. SAE J1939 combines all the incoming signal data into specific parameter groups (PG), which means that Kübler Sendix encoders can be adapted to virtually all customized applications that have an integrated J1939 protocol.

Encoder implementation SAE J1939

• PGNs that are adaptable to the customer's application
• Resolution of address conflicts (address claiming (ACL))
• Continuous checking whether control addresses have been assigned twice within a network
• Change of control device addresses during run-time
• Unique identification of a control device with the help of a name that is unique worldwide
• This name serves to identify the functionality of a control device in the network
• Predefined PGs for position, speed and alarm
• 250 kbit/s, 29-bit identifier
• Watchdog controlled device

A two-colour LED, located on the rear of the encoder, signals the operating and fault status of the J1939 protocol, as well as the status of the internal sensor diagnostics.

Main features:

• Flange diameter: 36 mm
• Depth: 43,6 mm to 54 mm
• Blind hollow shaft diameter: 6 mm to 10 mm
• Shaft diameter: 6 mm to 8 mm
• Protection rating to EN 60529: IP67, IP69k
• Operating temperature range: −40 °C to +85 °C
• Resolution: 14-bit
• Max. speed: 6 000 rpm
• Electrical data: Supply voltage: 8 V_DC to 30 V_DC

Programmable parameters:

• Resolution per revolution
• Total resolution
• Preset value
• Cycle time BAM
• Cycle time CMDT
• Bus termination