Selection of DAQ for my application

[Grey]

Hi Friends,

I have a new project with me and now I'm in the process of selecting hardware and estimating costs.

Please find the attached picture that describes the signal what i need to capture, measure and analyse.

i'm thinking which DAQ device will be suitable for this kind of signals...

one more question,,,,normally Test engineers will decide them self for selection of Hardware or they go for NI-local office for advise?

Thanks.

[mwebster]

That's a relatively slow signal, so sample rate isn't a problem. Looks like 100Hz would probably work, 1kHz almost definitely would. However, none of NI's DAQ cards are going to measure that kind of voltage directly. There are DMM cards that would, but that's probably more than called for here.

What you need is some kind of signal conditioner between those high voltages and your DAQ card. You might go with some kind of resistive voltage divider feeding into a Dataforth isolation module to prevent damage to the daq in case a wire comes loose and applies all that voltage straight into your DAQ. Pretty much any DAQ card NI sells should be able to read the signal in. Accuracy is going to be a product of the DAQ, the isolation module, and the tempco and drift of the resistors in the divider but depending on what you're doing with the signal after acquisition, may not be much of an issue.

I might not need to say this, but make sure you seal all the high voltage stuff away behind finger-safe barriers in your test system. 400V isn't like regular old wall voltage.

Regards,

Mike

[Grey]

Thanks for the detailed info.I forgot to mention that i am going to use 100:1 probe for signal conditioning

hello mike, thanks for your advise.

[JamesMc86]

The highest values we have for AI is 300V rms so it looks like it may be just short but for reference, for low channel count that is the 9225.

In terms of your other question always feel free to get in touch with your local branch if you need advice.