Sensor Bus Signals; Good thing or bad

Having sensors on a bus such as CAN or LIN rather than point to point wired, Is that a good thing or a bad thing. Is it easier to diagnose a bussed sensor or does it make it more complicated. It seems like with a bussed sensor there are much fewer connections and a much smaller harness so that connections are more robust. Also OBD can work much better with bussed sensors but there must be some tradeoffs.

Bill

Reply to
Bill Schuh
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I was reading up on this CAN system that is coming out soon, (Controller Area Network). I believe that's what the acronym stood for. From what I could understand, the sensors are still point to point wired to the controller. The only thing that seems to be bussed is the modules controlled by the central controller. I haven't been an auto mechanic in many years, but on the transport jets I work on, it's the same way. Ours are called ARINC 429 busses and all sensors are point to point wired to their respective modules, all modules are connected to the other modules throught the ARINC bus. You troubleshoot a sensor failure just as you would in any analog system. The bad, head scratchers happen when one of the modules has an intermittent short where in the bus port, or the two wire bus has floating grounds, etc. The ARINC system came out in the early '80's and we had some serious headaches with it until Boeing did some software corrections and increased bus wiring quality. I would imagine there will be some serious teething problems with the CAN system and you automotive techs will have to work with the mfrs. to sort it out.

Garrett Fulton

Reply to
gfulton

This is the way current On Board Communications work (CAN, ISO, and SAE J1850). The upgrade to CAN is mostly software related.

Similar problems to what we have now. The infamous Network Communications Errors (UXXX codes). Multiple modules report failure to communicate with module Y and the tech has to figure out if the problem is with the non communicating controller, the harness, etc.

I don't see any additional headaches with the newer CAN systems (in fact can is used on some cars now) with the exception of possibly more communications errors resulting from the faster speed and greater throughput of the bus.

Reply to
saeengineer

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