swinchen
Newbie level 1
Hi All. I am developing an oceanographic data instrument that need very accurate (+/- 0.01 degrees C) temperature detection capabilities. In fact +/- 0.001 degrees C would be preferable. I started a design that involved a precision current source, high-quality instrumentation amp. Seeing I am only interested in a narrow temperature range (-5 - 25 degrees C) I followed the instrumentation amp with a difference amplifier to remove the baseline voltage, and scale it up to the full scale of the A/D. I was going to do a 4 point measurement on the RTD to avoid any wire resistance effects. Then I found this: https://www.analog.com/library/analogDialogue/archives/34-05/sensor/index.html (Namely figure 9)
AC-excitation of the RTD seems to have a number of benefits. Does anyone have experience with this? Is this considered on of the "best" ways of measuring an RTD?
What I would do here is reduce the reference resistor so the AD would be full scale over my desired temperature range, and use the built in 6-bit DAC offset to remove the baseline from the RTD.
Any comments or tips would be greatly appreciated.
Thanks,
Sam
AC-excitation of the RTD seems to have a number of benefits. Does anyone have experience with this? Is this considered on of the "best" ways of measuring an RTD?
What I would do here is reduce the reference resistor so the AD would be full scale over my desired temperature range, and use the built in 6-bit DAC offset to remove the baseline from the RTD.
Any comments or tips would be greatly appreciated.
Thanks,
Sam