is it possible to multiplexe 8 analog sensors output into one PXI4472 channel?? can PXI4472 recognize those signals??

[a 11]

I have around 64 analog sensors to connect to PXI4472. Instead of buying 8 PXI4472, is it possible to multiplexe 8 analog sensors output into one PXI4472 channel?? can PXI4472 recognize those signals??

[LoganS]

Such a set up is not recommended. Some of the drawbacks are:

1. Depending on how you plan to multiplex the signals together (SCXI/PXI switch, 3rd party mux), you could very easily be introducing noise to your system.
2. Multiplexing the signals together into one line limits your sampling rate to the switching speed of you multiplexer device.
3. You will probably need to spend more time developing handshaking schemes in order for switching and acquisition to occur in such a way that you don't miss signals that you want to acquire.

These are only some of the drawbacks to this setup. All in all, the only functionality of the 4472 board that you would be left with is it's ability to sample all eight channels at the same time. So, you could multi
plex all the signals together, but doing so is not recommended.

However, I have a couple of questions. Do you want to sample all 64 sensors at the same time? Assuming that you are not, how are you planning on multiplexing the signals together? What kind of a chassis are you working with? Please let me know.

Logan S.

[a 11]

Hi Logan,

Thanks for answering my question. Actually, I am have around 64 Pt100 temperature sensors. Temperature signal is not a rapidly changing signal. So, instead of buying 8 PXI4472 modules, I am planning to multiplex 8 sensors into one PXI4472 channel. Therefore I will only need one PXI4472 module. Also, multiplexers that I am planning to use are not NI product. They are multiplexer that designed for use with RTD temperature sensor.

The chassis that I am planning to use is PXI1045. But I still have not confirmed yet.

As you mentioned, the PXI4472 doesn't seem to be a good choice for collecting multiplexed signal. So could you please advise me a better solution for my system? Which PXI card I should use? Thank you very much.

Best regards,
Ale
x

[LoganS]

Hi Alex,

The NI-453x series High Precision DAQ are designed for temperature readings, but if you are really interested in your different options, I would recommend that you call NI and speak with a sales representative. They should be able direct you to several different options to fit into your measurement system.

Good luck!

Logan Sheen

[a 11]

Hi LoganS,

So does NI-453x series supply reading multiplexed signal?

Thanks

[LoganS]

Hi Alex,

If you are asking if you can multiplex signals into the card from your 3rd party multiplexer, the answer is yes. You just need to make sure that you are sampling information at the right time relative to your switching in the multiplexer. Good luck!

LoganS