Q: Is it possible to monitor an external voltage or the Data Logger Sensor Power?
A: You can add an “automatic sensor power monitor”, that appears in the Data Log file.
It will monitor if Sensor Power is available during the measurement cycle.
C: The input voltage on an analog port is limited to 10V. Use a voltage divider and supply the output to an analog input port.
– A free analog port on a ML-x17 data logger (choose input voltage) or ML-OI-AD-10V option board.
– Two resistors (10k).
– If only check for Sensor Power available, a digital input port can be used.
Formula: V out = V in * (R2 /(R1 + R2))
Analog (and digital) input ports are limited to 10 Volt.
U = top line connected to 12V sensor power, bottom line connected to Gnd.
U2 = divider output.
(Use a warm-up time on the analog input port).
Top wire = battery power positive (U)
Bottom wire = Data Logger GND and battery negative.
Middle wire: divided voltage (U2) connect this wire to the available analog port. With two equal resistors, readings on this port will show 1/2 input (battery) voltage. Use the min-max calibration to get the correct value or use a Derivered Channel to multiply the reading by 2 to get the actual battery voltage.
Please read the sections 4.11 and 4.35.2 from the manual:
Be aware the voltage divider is consuming power: 12V /20k = 0,6 mA –> 0,72 mWatt, add this to the power calculations, if you use the Data Logger power..