# IN-Z61 pulse count interference

**URL:** <https://community.openenergymonitor.org/t/in-z61-pulse-count-interference/21264>\
**Category:** Hardware\
**Tags:** pulsecount, gas\
**Created:** [8 September 2022 08:38 UTC](https://community.openenergymonitor.org/t/in-z61-pulse-count-interference/21264 "2022-09-08T08:38:50Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![steev](https://community.openenergymonitor.org/letter_avatar_proxy/v4/letter/s/9d8465/32.png) [@steev](https://community.openenergymonitor.org/u/steev)\
**Post date:** [8 September 2022 08:38 UTC](https://community.openenergymonitor.org/t/in-z61-pulse-count-interference/21264/1 "2022-09-08T08:38:50Z")

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I have an Elster gas meter and purchased an [IN-Z61](https://www.smartenergy.honeywell.com/product/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?

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**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\
**Post date:** [8 September 2022 13:26 UTC](https://community.openenergymonitor.org/t/in-z61-pulse-count-interference/21264/2 "2022-09-08T13:26:12Z")

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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.

> [@Readings off](https://community.openenergymonitor.org/t/readings-off/20176/2):
>
> 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. I suggested adding a note about this to the Wiki in January - it’s not happened. I also have an optical pulse sensor, but that’s connected to an emonPi; so not directly relevant. That has on occasions picked up a nearby fluorescent lamp (with a thermal starter) being switched on or off. Others…

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**Author:** ![steev](https://community.openenergymonitor.org/letter_avatar_proxy/v4/letter/s/9d8465/32.png) [@steev](https://community.openenergymonitor.org/u/steev)\
**Post date:** [8 September 2022 13:43 UTC](https://community.openenergymonitor.org/t/in-z61-pulse-count-interference/21264/3 "2022-09-08T13:43:38Z")

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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…

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**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\
**Post date:** [8 September 2022 13:47 UTC](https://community.openenergymonitor.org/t/in-z61-pulse-count-interference/21264/4 "2022-09-08T13:47:58Z")

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It did for me.

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**Author:** ![steev](https://community.openenergymonitor.org/letter_avatar_proxy/v4/letter/s/9d8465/32.png) [@steev](https://community.openenergymonitor.org/u/steev)\
**Post date:** [11 September 2022 09:42 UTC](https://community.openenergymonitor.org/t/in-z61-pulse-count-interference/21264/5 "2022-09-11T09:42:15Z")

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Confirmed that worked perfectly. Thanks for the help!