Hello,
I am trying to read a Lastem C100A tipping bucket with a CR1000X using the PulseCount instruction with PConfig = 1. I run some tests in the lab, moving the bucket manually, but no rain is detected by the datalogger.
The voltage at the P1 terminal, where the rain gauge is connected, is correctly 0V when the switch closes, but it is only 0.83V when the switch is open, instead of 5V. I think this is the reason for the no rain detection. Do you have any suggestions on how I could solve this issue?
I also measured the resistance on the wires of the tipping bucket, it is 0 with the switch is closed and about 20 kOhm with the switch open.
Thanks for your help.
The datalogger channel has an internal pullup resistor of 100kOhm. That 20kOhm in the sensor is pulling the voltage down. Most tipping bucket rain gages are designed to be an open circuit between tips.
Without modifying the tipping bucket sensor, a stronger pullup resistor is needed. Adding a 20kOhm resistor between 12V and the datalogger channel should work. That would raise the open voltage to about 6V, which would read as a high state on the channel.
This post is under review.