How Can I Create A Custom Excitation Voltage For My Signal Conditioning System? Hardware: SCC>>Carriers>>SC-2345
Problem: I have a transducer / sensor that needs a custom excitation (example +12 V) voltage. How can I create a custom excitation voltage using my SCXI-1180 or the SCC-FT01 module for my Signal Conditioning System? Solution: The best way to create a stable, non-noisy custom excitation voltage for any sensor or transducer is to use an op-amp to get the appropriate voltage level in conjunction with a low-pass filter to protect against any noise. For example, lets say you want a +12 V excitation voltage. You would want to take the good, clean, stable +5V signal from your E-series DAQ board and pass that through a lowpass filter (cutoff of 50 Hz would be good). After the lowpass filter, you want to use an op-amp powered by +/- 15V rails (really anything as long as the difference is greater than your desired excitation voltage). If you are using the SCC-FT01 module, you have access to these lines. Now, run the +5V supply to the non-inverting input. Choose appropriate resistors so you get a gain of 2.4 (2.4 * 5 = 12). The output of the op-amp should be a very stable, clean 12V signal which will make a great excitation source for transducers and sensors. The best design would probably be to create an active lowpass, butterworth filter with the required gain, thus combining the two stages of this circuit. Related Links: Product Manuals: SCC-FT01 User Manual Product Manuals: SCXI-1180 User Manual Product Manuals: PCI E-Series User Manual Product Manuals: SCC-2345 User Manual Attachments:
Report Date: 09/16/2003 Last Updated: 07/21/2004 Document ID: 31FH2UW0 |
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