Hello,
Can someone suggest how to connect the Digimesa FM935-1500
https://www.tme.eu/en/Document/e44ffff8809c5a2143a01abd4a419033/935-1500X.PDF
to CR1000.
And do I need the resistor and capacitator showed in the data sheet?
If you use a P channel in switch closure mode, it will probably work directly on the CR1000. There is a chance that the datalogger won't pull the voltage high enough.
If the first option isn't working, use a 100 kOhm resistor from 12V to a P or C channel. It should read just fine them. Switch closure mode uses a capacitor for debounce. High frequency mode does not debounce.
Thanks, it worked actually directly in P, had the wrong type of signal selected previously.
However it is flactuating in sample value, for example 4 and 5 pulses/s. If doing averages of 4 s, still every other average flactuates. The average value between samples or 2 averages seems to be correct, but I would like to know how to correctly choose sampling time or output time to have stable value.
If you do averages on a longer time interval, you will see more resolution.
For example if the sensor outputs 4.5 pulses per second and you use a 1 second scan, one scan will have 4 pulses and the next 5 pulses. Scan to scan, the flow number will bounce back and forth. The resolution on a 1 second scan is 1 pulse per second.
If you did a 10 second scan(or saved an average to a 10 second table), you would get 45 pulses. The average is 45 pulses/10 seconds. The average will correctly show 4.5 pulses per second. You wouldn't see the reading bounce on the longer time interval.
The resolution on a 10 second interval is 1 pulse/10 seconds, which is 0.1 pulses per second. The resolution on your average goes up with longer intervals.