06-04-2012 03:24 PM
Hi, I've got a question here:
Is there a National Instruments Data Acquisition Product that is compatible with several sensors that measures Relative Humidity, Irradiance, Vibration, pH and Specific gravity? If yes what are the requirements for each sensor type to be compatible with the said DAQ product?
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06-05-2012 04:13 PM
you can use any NI DAQ product to do those measurements as long as the sensors have a voltage range
form 0 to 10V.
The selection of the device you use depends on variables like portability, sampling speed, buffer size, etc.
You can compare different DAQ families here.
06-11-2012 02:42 AM
1. At first you need to define your requirements. (Range, resolution, accuraty, update rate, traceable?, ..., price)
2. Than you need to find sensors (or systems) that fullfill your needs. (Depending on 1. that could be sometimes challenging )
3. If you have a choice between different sensors/systems:
DAQ with voltage input is most common, some sensors need 'special' voltage inputs: low voltage, noise filtering for Thermocouple, very high impedance for pH-sensors if connected without bufferamplifier.
Industrial sensors often come with current loop output (20mA) or a 10V voltage output. Usually they are robust, well specified, come in nearly all kind of flavours .. but are pricy (You get what you pay for)
Vibration transducer want charge amplifier or (more common) a current exitation (IEPE) .
Bridge type or resistive sensors want a voltage exitation.
Specific gravity sounds like a complete system so maybe a direct connection to the PC via serial / USB or Ethernet is possible/needed, but could be a high resolution DC-accelerometer or a <10$ MEMS with a I2C connection that would need a digital IO connection...
Irradiance could be anything between a LDR/Photdiode and a laserbeam analyser ...
Next: Do you need it high reliable 24/7 , portable , flexible .... ??
A PXI system could be needed or maybe a USB multi IO DAQ is fine (about two to three orders price difference )
Anyway I'm shure you can do it with NI Hardware and LabVIEW