IN-Z61 pulse count interference

I have an Elster gas meter and purchased an IN-Z61 pulse counter (I believe it’s a reed switch) to monitor my gas usage. It’s connected using the provided 5m cable to my emonTx across IRQ/GND.

The emonTx does register pulses, but at a higher rate than the meter is actually spinning, and also it seems to pick up some interference from a nearby microwave when it’s running. Do I need to add a resistor to mitigate this and if so, how do I calculate what value I need?

Welcome, Steve, to the OEM forum.

I doubt it’s a resistor you need, more likely a capacitor to short-circuit the high frequency a.c. that’s being picked up by the cables, and maybe to get rid of contact bounce too. I used a 0.1µF wired directly across the reed switch, but connecting it at the emonTx end should be OK.

Thanks! Do you think that would sort out debouncing the pulse counter signal as well? I’m not an electronics person as you can see…

It did for me.

Confirmed that worked perfectly. Thanks for the help!

1 Like