CAN-LAN Protocol Interface
As products mature and become obsolete how can you keep support for legacy equipment? This project was based around this need. The customer has a large and complex existing RF ATE which needed new switching units to replace the ageing legacy units. The communication of the legacy units was a CAN interface whereas the identified replacements were SCPI controlled over an Ethernet connection. To allow the minimum of disruption to the existing system and possibly more importantly the existing test software a simple protocol converter was created to monitor the CAN bus for incoming commands and re-interpret these into out-going SCPI commands.
The communication protocol was reverse engineered by connecting into the system a CAN bus monitor and the specific CAN commands recorded for the switch commands sent by the control unit. From this information a lookup table was created allowing translation from CAN command to the relevant LAN command.
The main component selected for this project was a National Instruments sbRIO 9606 board. This hardware platform was selected as it gives a self-contained board with a Real-Time processor and both CAN and Ethernet interfaces. This hardware can be easily programmed with National Instruments Lab-VIEW RT meaning that the heart of the new unit is based upon industry standard programming and COTS hardware. This is built into a custom design 1U 19" rack chassis with the associated hardware required to power the internal electronics.
Configuration of the switch unit LAN addresses, CAN ID’s and also the command conversion look up table are provided in simple ASCII files which are held on the sbRIO internal memory. This provides the customer with the flexibility to modify the protocol converter units should the new switches be replaced again.
A serial interface on the sbRIO is utilised to control the graphical LCD screen, which displays the current configuration of LAN addresses and CAN ID’s
|Dimensions:||H44mm x W585mm x D350mm|
|Electrical:||100 - 250VAC 240W|