Control technology
Source: CAN Newsletter March 2010
HSM Hohenloher Spezial-Maschinenbau located in Neu-Kupfer (Germany) develops forestry vehicles. The vehicles include the series skidder, forwarder and harvester cover. Whet her with a winch or crane, whether compact and for all terrains or with a hydrostatic one-motor and two-motor drive: All products make use of 32-bit ecomatmobile controllers by ifm electronic.
Whereas in the past different control modules were used in the individual product series, these tasks are now performed by the controller units. The complete application program with the different configuration options is stored in its large memory. In production the individual hardware modules are combined and the software options are enabled. The controller processes all sensor, actuator and control signals of the system, which are transferred on the CAN network for mobile applications via the decentralized I/O modules of the individual machine parts. Moreover, it coordinates the signals of the radio remote control for the winch and relocation of the vehicle.
Despite the size of the application program and the complexity of the control logic the cycle time is so short that four independent CAN interfaces can be read and processed in parallel.
The CAN interface 1 with its standardized CANopen protocol is responsible for the communication with the joysticks with bus capability and the decentralized I/O modules for the individual aggregates. The CAN interface 2 handles the exchange of data with the central display. This is for example made possible by the crane controller, which can be individually adjusted to up to five drivers for sensitive working and an integrated diagnostic and calibration mode. The communication with the engine is handled by the interface 3. Here the data is transferred by means of the SAE J1939 protocol. This guarantees the use of economical and mainly ecological diesel aggregates of the latest generation in accordance with the applicable emission standard tier 4 and the tier 5 standard which came into force in September 2009. The CAN interface 4 is used for the harvester. Via the interface the control data is exchanged with the harvester head.
