Hello everybody, Here I want to take some guidance before i can start my work for new product development.I am going to make product in which main CPU card will be communicating with other 16 scanner card.So I am looking for which communication method I have to adopt for communication between CPU and scanner cards.I though like I should use parallel bus interface like PCI or VME but it is very costly.Even Embedded card based on that are very costly so now I came to serial interface. Now I am thinking for any good fieldbus protocol like profibus,lonworks,interbus etc. If i am going for Profibus,then can anybody help me how I have to go?whether I have to implement by using specific protocol chip or by using software protocol with RS485 only? Please suggest me regarding this. Please reply me also my email id: premjic@masibus.com Thanking you, regds, Premji Chaudhari.
Premji, Probably the most important thing to consider in this decision is exactly how much data you need to transfer and at what speed. This will have a pretty dramatic effect on your selection of a physical media and depending on the processor you choose, you'll have to consider the processing power needed to achieve that throughput. As far as simplicity goes, however, a MODBus fieldbus with a vanilla RS-485 physical interface is pretty simple to implement. Regards, Jay
Hello Sir/Mr.Jay Thank for posting reply, As per you,I have to need enough processing power that I will have becoz I am going to select 32 bit with more than 100MHz clock microprocessor along with good system memory.So there is no doubt for processing power.Actually I am going to make product in whcich one main CPU card will be communicate with other 16 scanner I/O cards in same device.Now These scanner cards have one 16 bit microprocessor and some signal conditioning circuit by which they will process on field i/p data and they will be time-stamped.Now I have to implement proper methos between main CPU card and this scanner card so main CPU card will take data from these scanner cards. Initially I thought by using parallel interfacing using PCI,VME etc.But for this I have to pay much for readymade embedded CPU board as a main CPU in my product.Then I came to serial bus interface between these cards. So I want to implement such a protocol which has good ability,throughput,deterministic,error-correction,user fexibility,future expansion,low cost etc. Also to implement fieldbus,there are asic chips are available,but by that way again cost will come in to way.Although I can develop by software writing and using RS485 but I have to pay my time.so there is a hesitation... If any comment/idea,plz forward me. Thanks again. Premji.
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