I'm looking for advice. I'm designing a battery monitoring system and would like to base it on the PC-104 form factor. I need to measure ~200 battery voltage taps from a string of lead-acid batteries, ~ 3VDC each. Additionally the system needs to measure some nearby temperatures (~10).
- A)Should I consider a PC-104 CPU board that integrates the A/D function on-board? Why or why not? B)Or, use a separate Analog input board?
- I would like to switch 16 signals at a time into the data acq. front end. I plan to use solid state relay switching board (custom designed) controlled by the CPU. Anybody do something similar using different switching devices (optical isolaters, voltage comparitors, ??) Would it be a good idea to digitize the data onboard these cards, vice #1 above?
- I need a system that will last a long time. What can I do to avoid getting stuck with an obsolete PC104 CPU board down the road, if no longer supported?
- I would like to scale this system to a general purpose data acquisition system (~100 channels) that would acquire 100KHz signals. With a PC104 based system measuring lots of data fairly fast, what's the best way to stream this data to disk quickly? Is it practical with the PC104 form factor? I could divide and conquer. Could someone point me to an example of how to specify such a system, so I could identify the bottlenecks?
Thanks in advance for any help. I don't expect anyone to design this for me, but hopefully give advice to keep me from heading down the wrong path and wasting time. If I can't design something quickly, I probably won't get the job.
P.S. I'd like to use QNX as the embedded OS, but I'm certainly open to other suggestions.