Is there a single SCXI module suitable for mixed sensor inputs?

[CAS]

I'm am attempting to put together an SCXI system to acquire signals from a number of different sensor types. I have a large number of thermocouples for which I have decided to use the SCXI-1102 modules. I also have a single pressure transducer (spec unknown so I'll assume strain gauge type), a single accelerometer (again, spec unknown) and possibly some straight forward voltages (count and spec unknown so assume -10V to +10V max range).

Is there a single SCXI module through which I can acquire the pressure transducer, accelerometer and voltage signals? Or maybe just use 2 modules instead of 3 if I have a SCXI-1530 for my accelerometer and a different module for the voltages and pressure transducer? I was looking at the SCXI-1121 which sounds promising for the voltages and pressure but then was unsure as to which terminal block to use to allow the combination of signals (I could possibly live with a -5V to +5V range if necessary).

(Extra info: I am using TC-2095 blocks with my SCXI-1102 modules so can't really use spare inputs on those for voltage inputs).

Thanks for any help.

CAS

[RER · Accepted solution]

Dear Cas,

Thanks for your enquiry. You have obviously done a great deal of research into this matter already. I am afraid that it is unlikely that you will be able to use a single SCXI module to carry out all the functions you have listed. As accelerometers require such specialised conditioning, it will require a dedicated module - as you already mentioned, something like the 1530 (4 channel accelerometer input module) would be ideal.

However, you have a number of different options for the pressure, voltage and temperature measurements.

For example, you could purchase a 1520 mudule for your pressure measurements, and then use a general purpose 1102B for the voltage and temperature (you would require the 1303 isothermal terminal block to condition the thermocouple readings... and bypass the CJC technology for the voltage readings).

Or, perhaps you could use the 1102 thermocouple module for your temperature readings, and then use a 1102B to take the voltage and pressure readings. Obviously this would involve making your own bridge configuration for the pressure sensor, but that should be fairly easy.

Before you make any final decisions, I would recommend that you call your local branch of NI and speak with a sales representative. Perhaps, a member of the field sales staff could actually come to see you to discuss the matter face to face.

lastly, it sounds like you have a relatively high channel count for some of your readings, which is why you have decided to use the SCXI platform. I was just wondering if you had considered compact DAQ (cDAQ), which combines DAQ hardware with signal conditioning. Higher spec, ease of use, lower channel count. Swings and roundabouts I guess.

I hope this has been of some use to you.

Best wishes,

[CAS]

Dear Rich,

Thanks for the advice. I will look at those SCXI options in detail when I get the full spec of my sensors and see what combination works best. I started out thinking that, as many of the modules can handle signals from a range of sensor types, that the intention was for a single module to be used for a mixture of sensors. Now I see that that is not really the case.

I have indeed got a high channel count for my thermocouples (252) and a low channel count for all the others (which now also includes 8 strain gauges). I had not thought of using SCXI for the TCs and cDAQ for the others (I think that's what you're suggesting). I will look in to that.

Thanks again.

CAS