Thomson Electrac HD Linear Actuator Motion Control per CAN Bus (ePub)

This application note focusses on the Thomson Electrac HD series of linear actuators. They support two higher-layer protocols based on Controller Area Network (CAN): CANopen, and SAE J1939. You can control the actuators merely with hardware switches (Start, Stop, Forward Motion, Backward Motion), but, in addition, both CAN protocols allow to regulate the linear speed.

If your application requires mere motion control (Start, Stop, Forward Motion, Backward Motion, Speed Control), you are better off with SAE J1939 because you don't need to install the protocol stack. The Electrac actuator supports some SAE J1939 protocol features (e.g., the address claim procedure), but you can ignore the protocol requirements and control the linear motion with mere CAN Bus data frames (using a 29-Bit message identifier). Thus, "CAN Bus communication" describes the operation mode more accurately.

The CAN/J1939 approach will shorten the development cycle tremendously, which is why the focus is on SAE J1939 and not CANopen.

In view of various undocumented eccentricities, you should not start programming the Electrac per CAN/J1939 without reading this document. The Electrac user manual was primarily created for installation, while this application note provides a valuable source for programmers.