Could you help me with this:
I have a sensor (to measure flow of water) with pulse output, the supply voltage of the sensor is 24 Vdc, i want to connect this sensor to a Pulse input of the CR800, the output of the sensor is "PNP open collector", so the voltage of the pulses will be 24 Vdc, can i use a voltage divider to reduce this signal to 5 Vdc (or similar) and connect to the Logger?
This could work? i read that the Pulse inputs have a Pull up resistor for high frequency and im not shure if this configuration can damage the logger or cant work, there is other way to connect this sensor (with 24 Vdc) to the pulse input?
Thank you in advance
The manual states a maximum input voltage of 20 volts on the pulse ports.
Easy to make a voltage divider to drop it to below that, you don't need to take it all the way down to 5 volts.
Are you using a high frequency measurement? If so, the voltage has to fluctuate between 0.9 and 2.2 volts for the change of state to be noticed.
The pull-up resistor mentioned has a resistance of 100k so as long as the resistor in your divider network that is connected to ground, can pull that down below 0.9 V you will be OK. (In round numbers something 10kohms or less will be OK.)
Understood!!
Thanks for the support!!!
Regards