Distributed signal acquisition of multiple analog sensors?

[Lysandros]

Dear NI-forum members,

for a general aviation aircraft test bench, we are planning to gather multiple analog sensor signals from different parts of the aircraft and acquire them for real-time simulation in a PXI-plattform.

Because of electromagnetic interference and relatively long cables (4-5m), I believe that this poses a challege. Is there a possibility for distributed signal acquisition of analog signals and direct conversion to digital form, before transferring them the longer way to central PXI-system?

Best regards

Lysandros

[crossrulz]

I would look at an Ethernet cDAQ.  You can have as many chassis as you need at their locations and then run CAT5 cables to a network switch.  Your controller then just reads all of the data using the normal DAQmx API.

If going this route, I would get a really good computer instead of a PXI.

[Lysandros]

So this means, that for evey analog sensor I need one separate Ethernet cDAQ module?

[crossrulz]

You can get cDAQ chassis with multiple slots.  For Ethernet control, it looks like you can get 1, 4, or 8 slots in a single chassis.  You then choose the module based on your sensor.  For simple voltage measurements, there is the 9205 which has 32 analog inputs.  So you could have 256 sensors in a single chassis.  Of course, you need to choose the modules based on what your sensors put out.

[Lysandros]

That sounds like a good idea.

But I would prefer to condition& digitalize the analog signals directly after the sensors, in order to avoid interferences in the long distance to the central acquisition hardware.

So basically we would need mulitple distributed A/D-converters that acquire the sensor readings and send them in a digital format with star-topology to the cDAQ for example.

Thank you & have a nice weekend !

[crossrulz]

Having the cDAQs very close to the sensors was the point.  They are doing the digitizing and then sending the data over Ethernet to the central computer.