Verifying Sensor Voltages

Here is an overview of the ADC voltages expected on a new AQ board. Every board has been tested, so this is mostly posted for reference in case of suspected calibration problems.

To check the ADC voltages, mount the board with some standoffs, place it level and make a 30 second log. Then use the log viewer to check each individual value. Allow for around a 10% tolerance on each value, and that the values will vary with temperature and/or other factors, as noted.

The reference values below were taken with the AQ board in a level position, at room temperature (~20C).

Sensor	V_Log	Expected Value	Image
RATEX	0	Rate gyro output, static reading around 1.35 volts
RATEY	1
RATEZ	2
MAGX	3	This looks like a band of voltage somewhere in the 1-2V range. It should not be zero, a straigh line, or 3.3 volts.
MAGY	4
MAGZ	5
TEMP1	6	Centigrade temperature of IDG500. Around 1.25 volts at room temp
VIN	7	Voltage read from R3, R4 voltage divider. Rev1 board (4.7k): LOG_VOLTAGE7 / .221 = Vin; Rev2 board (8.45k): LOG_VOLTAGE7 / .136 = Vin;
ACCX	8	Acc output — around 1.65 volts.
ACCY	9
ACCZ	10	Acc Z output — around 1.83 volts.
PRES1	11	This is the normal pressure sensor installed and should be about 2.65 volts at sea level. It will go lower in voltage with higher altitude.
PRES2	12	Pressure sensor with tube (not installed on beta boards) reads about 2.65 volts at sea level and goes lower with higher altitude. If installed, it should be within a .2 volts of other sensor.
TEMP2	13	Centigrade temperature of ISZ500.  Around 1.25 volts at room temp. Image shows board heating up from freezing temperatures.
TEMP3	14	This is Kelvin temperature represented by a thermister on the board. Coming out of the freezer it can be near 3 volts. As the thermister heats up, its resistance goes down and the voltage will go below .5 volts.  Image shows board heating up from freezing temperatures.