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.
Hi Everybody, Thanks for support, Actually now I understood that I have to go for protocol which can support file transfer. Here I am giving my overview.I have 16 scanner card,each has 8 analog input and 32 digital input.Scanner card will take data from field and store it temporarily with time stamp.Here we have to go with worst case consideration to get maximum data for scanner temporary storage.Each scanner card is taking 10 ms to scan it's inputs.After every 10ms scanning repeats.Also this is parellely with all scanner cards.so in 10 ms,maximum data collection at local memory of scanner card is like - 16 byte for 8 analog inputs. - 32 bit for 32 digital inputs,so 4 byte. - 3 byte for time stamp of 8 analog inputs so total time stamp for analog input is 24 byte. - similarly for digital inputs,32 X 3 = 96 bytes. So here in each scanner card has total bytes storage is 140 bytes.just after every 10 ms.This is for worst condition,Actually it may not be.Although we have to design by considering worst case,so it will not make never problem in future. Now here after every 10 ms,it is not possible to make communication between master CPU and these scanner card to take data from each scanner one by one.So here scanner card will store some data for temparory.Suppose we take 1 second.i.e.After every 1 second CPU wants to take data from same card,then just see storage in scanner card. In 10 ms,it was 140 byts.So in 1000 ms = 1 sec it will be 140,000 bytes. Now see this is for all scanner cards.(in worst case.practically is impossible). Now CPU will start to take data from each scanner card one by one with even high speed like 1 Mbps.but this comminication is based on serial UART port or CAN bus.But here one limitation is much overhead exists.Because by this communication,After every one byte or 3 byte transmission,interrupt will be generated.So how many time it will generate,if we see for all card. So this is the big headache. So I am looking for file transfer protocol or aomething else.So it can transmit many data at only one interrupt generation. Please suggest me. Thanks.
Maybe you can consider Ethernet and TCP or UDP? With a 100Mbit/s link you can easily achieve the desired throughput, and in that environment you already have the File Transfer Protocol you need. Look at Keil's XC167 Eva Board (Microcontroller & Ethernet Hardware) + ARTX166, it already implements almost everything you need.
OK sir, Also I thought for this Ethernet and now looking for this only. Thanks,