Looking at the specs of the DT3010:
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> indicates that the inputs are spec-ed as 100Mohm, 10pF off/100pF on.
> That doesn't explicitly state what will happen in use, that actually the
> 100pF on is not at the same voltage as the 10pF off, which means charge
> injection will occur.
>
> I would be very disinclined (based on my philosophy) to make a board for
> market like this, without input buffers. I know it would add cost, but
> 16-32 extra op amps on a $2000 board would be a fair price to pay for
> the benefit of being able to advertize the product as such and to write
> a white paper about how your signals won't be read correctly when you
> connect a competitor's board to real-world sources without spending a
> several $1000s in time/materials to have an electronics tech. or
> engineer make you an analog buffer amp for each channel.
Certainly a fair design criticism. Whether it makes sense for them deoends on whether the extra would price them out of their target market which may not match your use of course. I know I've been frustrated a time or two by the thought "If only they had add/changed this one simple thing I could just use X rather than having to .... "
I've a bit of a soft spot for Data Translation. I did a project with one of their boards as a grad student and unlike some other boards I saw at the time they had enough information to program them w/o needing pre- packaged software.
I just realized that's 20 years ago. Time flies.
I have at least one board which is built more like I would expect, a
> 16-channel simultaneous sampling DAQ from Innovative Integrations (a DSP
> solutions vendor). That one has almost exactly the same input
> conditioning on each channel as I am going to be sticking on my DT3010s.
Hey at least you had the foresight to add room for signal conditioning. That gives you bonus points as far as I'm concerned.
Robert