On Thu, Feb 16, 2012 at 8:29 AM, Erik Friesen <e...@aercon.net> wrote:
> Another ignorant question, why is the industry so inclined to isolated IO? > vs single board designed systems where everything is layed out properly. > This just gets me, when trying to make a control system look neat, and you > have to use a hodge podge of different breakout boards, drivers, etc, with > a resultant rats nest of wires. The interface boards are essentially working as fancy fuses, because industrial environments are messy and confusing, with noise, interference, crosstalk, voltage surges and wiring mishaps due to things like technician error or 'conveyor chewed up the main cable harness'. It's easier to replace an interface board than the entire single board integrated controller. In the old days, the PC serial ports always had a socketed 1488/1489 i/o buffer chips on the motherboard; instead of blowing up the entire motherboard, serial port mishaps could be fixed by replacing the chip. Curiously, those chips were designed by Jim Thompson who's around in the sci.electronics.design newsgroup. Since then, they made protection circuits better and/or people stopped doing egregious things with serial ports---but still there's a standing recommendation to use separate PCI cards for serial and parallel ports interfacing to non-computer equipment, because they can be swapped out, unlike the motherboard built-ins. ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
