I am building an instrument that relies on a precision sensor module. The sensor is factory-calibrated, and outputs 0-10Vdc. I believe the factory calibration to be better than anything I can attain, and thus do not want to create my own calibration curve for the sensor.
I want to read this output with a 16-bit ADC; however, most ADCs only accept 0-3Vdc input. I will likely need an offset/gain op amp circuit between the ADC and the sensor, but I want this to be referenced to a known voltage reference. For example, I also want to run a known precision voltage reference through the offset/gain circuit to known that a given reading from the ADC corresponds exactly to a given reading on the sensor independent of temperature and everything else that could affect the reading. I want to be sure that I can determine the exact voltage coming off the sensor.
Can someone provide a schematic for such a circuit? Or at least point me to such a resource.
A number of commenters have asked about the specifics of my application (sorry! it took me a bit to dig up the datasheet). I am interfacing with an INFICON Priani Capacitance Diaphragm Gauge (a vacuum sensor). The device has a signal output with an absolute maximum range of 0-10Vdc; however actual measurements stay within the 2.2-8.68Vdc range. The accuracy of the voltage output is not stated because the device operates on a logarithmic scale. Voltage is directly proportional to the logarithm of pressure. The data sheet states the pressure measurement (not voltage) is ±15% accurate at 50 mbar, ±5% at 1000 mbar, and ±2% accurate at atmospheric pressure. The conversion factor is P = 10^(U-5.5) where P is pressure in mbar, and U is voltage.
The logarithmic output of the sensor is why I am concerned about accuracy (not so much precision). Errors in voltage measurement are amplified exponentially by the logarithmic nature of the device.