|
| The original assumption was that network errors on an Ethernet based network would most likely be caused by EM interference rather than saturation. I concede, if we are talking about errors caused solely by network saturation Ethernet wins out. You're going to make me go study everything I ever learned about CANbus aren't you? ;-). There is a protocol about how quickly a device rebroadcast if it's message is bumped by a higher priority message. The physical layer of ISOBUS attempts to address the likely hood of mechanical network failures by standardizing connections points. I'm just glad I no longer have to run a dozen wiring harnesses into the cab and find a place to mount 14 monitors, have you seen some of the pictures posted on here? I think there are many endusers who are excited about the things ISOBUS could deliver to them, reduction of cab clutter, compatability between implements of different brands. However, there has been a poor job of delievering the message of what ISOBUS is and what it can do.
I am sure there there is an instance whereby a device could short out and bring down the entire network. However, the several times I have had a device short out it simply disconnected from the BUS and everything else continued operating normally.
I still feel like the implement network needs to be common rail. I'm not sure what type of phycical network structure you are argueing for in that regard. We can't go back to every device being hardwired to a central hub or switch, even at a single implement level, which means each remote needs to have it's own switch incorporated into the device. Probably very doable., I don't have a grasp of what the cost to implement that would be.
There is a problem with the railroad example. I suspect that the actual control network onboard the engine is some sort of CAN most likely something similar to J1939 or 11783. The wireless control runs on a separate network and is bridged. The reliability of that system would start to break down if everything was communicating wirelessly.
I agree, if bandwidth requirements increase that will most likely be what happens in Ag, other network types will be layered on top of ISOBUS. However, ISOBUS is here to stay for machine and implement control.
Let's not kid ourselves, Deere hasn't been pushing this train, they have been standing in front of it most of the way. Flexicoil had a fully developed system in 1998. Deere was still arguing for 4.5V CAN until 2002.
Did you get a PID control loop integrated into your autosteer system?
Edited by Matt NCOK 5/13/2009 01:30
| |
|
ISOBUS – thoughts from a geek
