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How to manage 120*8*16 microcontrollers?

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ogden:

--- Quote from: JohanHoltby on June 02, 2019, 10:12:43 pm ---The bus speed only need to be about 500kbit/s when the data is fetch out from the system.

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How do you know which exactly channel contains data you are looking for? If you need to analyze whole set of data, it is: 16bits * 1MSPS * 8seconds * 120*8*16 = 245.7 Terabytes. Using 500kbps you need 15.6 years to read everything.


--- Quote ---I'm leaning to RS485 right now. Good or bad?

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Bad. It does not solve you anything, only adds additional networking layer to implement and debug. Get your data into Ethernet as soon as you can. Check what CERN scientists with LHC science instruments do.


--- Quote ---I will run in to problem if i try to program them before i place them if when I find a bug. JTAG might be an option if I use the STM chip maybe?...

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Self-programming over data interface.

Siwastaja:

--- Quote from: JohanHoltby on June 02, 2019, 10:12:43 pm ---No 1ms/sec is not critical and it's not a hard constraint but it would be nice to know what did happened in the system and when.

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Again, what do you expect to happen at such small timescale?

Power lines tend not to have such dynamics, there's inductance in wiring, and capacitance in loads, all over the place.

For some kind of EMI analysis, I'd kinda understand that, but then you would like to have even more bandwidth, and look at radiated electromagnetic fields.

JohanHoltby:

--- Quote from: ogden on June 03, 2019, 07:21:30 am ---How do you know which exactly channel contains data you are looking for?

--- End quote ---

Due to the nature of the system. If I see a problem i can follow the trace of clues and check for reasons without a need for a re run. Think of it like a LTspice simulation but on the real deal. I will not download all data only the data of interest.


--- Quote from: Siwastaja on June 03, 2019, 07:27:15 am ---Again, what do you expect to happen at such small timescale?

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Good point. Without a reason it would be stupid!
I hope to find the reason why the system is behaving like it is. So this is mainly a feature for debugging. Think of it as a 1Mhz oscilloscope that knows every thing.....42...;)

tszaboo:
What is the goal of the system? Overload protection? Diagnostics?
In any case, there is usually very little reason to store all these data, unless you work at CERN.
Your output is going to be 1 bit, the system is working or it doesnt work.
Let the microcontollers do their job, and analyse the data. Have an open collector output for faults, and something like 485 or CAN for communication.
Wherever it's possible, reduce the amount of data to something which is less. Do you need 1 million sample per sec from the microcontoller, or is it enough to have 1 sample of RMS value per second?

Or you can replace the microcontroller with a comparator?

JohanHoltby:
It's diagnostics. CERN would be nice but no I don't work there. The problem is that I don't know what I need to extract from the raw data. I want it all..... :)

But as you say. If I know what I want to know this is none optimal way of doing it, I agree.

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