I’m kinda of lost right now. Looking for some advice. I’ve purchased a emonTX v4 and a emonBase to monitor hot water consumption. The water meter has a reed switch pulse counter, where each pulse represents 10 gallons. I have a 40 gallons water heater.
I had a magnetic reed switch connected to an emonTH for my gas meter, that counted approximately 2.5 per pulse. The addition of a 0.1 µF capacitor across the reed switch completely eliminated the problem.
In your case, for “reed switch” read “water meter terminals”.
The software should have a “contact debounce” algorithm, but even if it’s activated (which it should be by default), it’s not totally foolproof.
Reed switches are well known for bouncing, both when making and breaking, the real problem is the software is so fast that it is able to count every tiny glitch as the contacts move over each other.
What do you mean “adding a 0.1uF capacitor to the reed switch”. Would I have to remove the switch and solder the capacitor or I could do this off the cables coming out the switch?
You do it wherever it’s convenient, either at the reed switch, somewhere along the cable if there’s an accessible joint, you can even do it on the pulse input on the front of the emonTx4 (the left and middle pins - you’ll need the plug but then it’s easy with screw terminals.)
(If you had the 2000’ of cable, there might be enough capacitance there and you wouldn’t need any more )
I have an accessible joint where the cable from the switch is attached to the Ethernet cable. Is orientation of the capacitor important? Or having it connected to the 2 cables is enough?
If it’s a polarised capacitor, then you must observe the correct polarity (pin 5 on the RJ45 is the earthy side, pin 6 will 0 V or +3.3 V). But at 0.1 µF, your capacitor is not likely to be polarised.
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