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Re: Data transfer for real time analysis

We are planning a data acquisition system with 4-12 sub units. Each sub unit

> produce data of 25MBit/sec. The distance between the boxes and computer is > about 2 meters. > I'm willing to transfer and analyze the data in real-time. I'm willing to > close a control loop in 1-5msec (I. wish 100usec ......). > What is the recommended serial protocol? > The sub units will be in-house made the host computer for data analysis and > storage will be a PC (probably with raid HD). > What communication HW should I use in my sub units? > What communication HW should I use in the PC?

I take it you're not moving much data per port. By my calculation, you can move about 25 bytes per port with 12 active ports if all the ports are on one

25Mbit/sec channel. These numbers do not include any overhead that my associated with the channel protocol.

Are we going to get a hint as to the application?

Reply to
Everett M. Greene
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Hi,

For the control loop, have you considered using an FPGA rather than serial links + PCs? A PID controller in an FPGA is quite straightforward to implement. I implemented a PID with data rates at 6MBps with frame rates of 10us, and then had the software just program in the control constants. In terms of serial links, I designed a simple point to point serial comms that sent out the data over an RS422 links (but maybe the best thing to use these days is LVDS), for reception in the FPGA that included the PID controller,

I guess it depends on what type of processing you want to do?

HTH

Paul.

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Reply to
Paul Taylor

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