Author Topic: Pulse output from a water meter (mechanical question)  (Read 395 times)

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Offline e100

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Pulse output from a water meter (mechanical question)
« on: February 12, 2018, 04:38:13 pm »
Is anyone familiar with this type of water meter that has a reed switch mounted above a dial with a magnet perched on top?
https://imgur.com/p9tJUrc
With the reed switched removed https://imgur.com/FA4IUWf
(The image gives the optical illusion of a hole through the plastic cover, but it's actually solid on top.)

Are these types of meters easily configured to read a different dial?
Do the red pointers simply pull off, and can I simply rotate the transparent cover so that the reed switch is over a different dial?



« Last Edit: February 12, 2018, 04:43:04 pm by e100 »
 

Offline capt bullshot

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Re: Pulse output from a water meter (mechanical question)
« Reply #1 on: February 12, 2018, 05:20:18 pm »
Don't know about your original quiestion.
What I did with one of these meters: pointing a laser at the fast rotating (black) wheel and detecting the intensity changes to have a real high resolution counter.
Safety devices hinder evolution
 

Offline e100

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Re: Pulse output from a water meter (mechanical question)
« Reply #2 on: February 12, 2018, 05:44:30 pm »
Don't know about your original quiestion.
What I did with one of these meters: pointing a laser at the fast rotating (black) wheel and detecting the intensity changes to have a real high resolution counter.

Interesting, specs for cheap 1mw lasers quote a lifespan of about 5000 hours or thereabouts, which is only 200 days if operated continuously. Do you get a longer life if you run at a fraction of full power or in pulsed mode?
 

Offline capt bullshot

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Re: Pulse output from a water meter (mechanical question)
« Reply #3 on: February 12, 2018, 05:59:35 pm »
Yes, the lasers lifespan was a concern - but turned out to be longer than expected. I've used a modded simple laser pointer (remove the battey and pushbutton). The laser output power regulation circuit was so primitive, I could modulate the output just by applying a 170kHz square wave as the power supply (instead the battery). The modulation was used to frequency selective receive the reflected light (ambient light suppression).
This thing worked for 4 to 5 years, then the water meter was replaced and I switched to inductive pickup - as the meter provided for that. I never saw the (el cheapo) laser degrade ...
Safety devices hinder evolution
 

Offline e100

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Re: Pulse output from a water meter (mechanical question)
« Reply #4 on: February 14, 2018, 03:03:49 am »
Replying to myself, relocating the sensor is possible.
The hardest part was making a tool to unscrew the metal retaining ring that holds the whole thing together.
https://imgur.com/Sx9zNYT
https://imgur.com/xVP4iBl
https://imgur.com/0VIRpvQ
 

Offline fourtytwo42

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Re: Pulse output from a water meter (mechanical question)
« Reply #5 on: February 14, 2018, 07:21:38 am »
Is anyone familiar with this type of water meter that has a reed switch mounted above a dial with a magnet perched on top?
https://imgur.com/p9tJUrc
With the reed switched removed https://imgur.com/FA4IUWf
(The image gives the optical illusion of a hole through the plastic cover, but it's actually solid on top.)

Are these types of meters easily configured to read a different dial?
Do the red pointers simply pull off, and can I simply rotate the transparent cover so that the reed switch is over a different dial?

In the uk I have a similar meter but fitted my own reed switch to it, the lowest order dial has a tiny magnet embedded in it, you can see it in your picture as a silver disk that operates the reed switch. My meter belongs to the water company so I could not possibly disasemble it to swap the pointers and i have to ask why you would want to do that ?
In my case the lowest dial does a revelution every Litre (horrid euro measure) and my software in the house just accumalates those the same as the meter does and displays the same total to a reselution of 1 Litre. Following your sugestion and moving the magnet dial to say 100's would mean my reading reselution would drop to 100 Litres and I cannot figure why I would want to do that  :-//
 

Offline jack-daniels

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Re: Pulse output from a water meter (mechanical question)
« Reply #6 on: February 14, 2018, 08:02:22 am »
Following your sugestion and moving the magnet dial to say 100's would mean my reading reselution would drop to 100 Litres and I cannot figure why I would want to do that  :-//

I think the dial the sensor is on is tenths of a gallon and the dial to the left is hundredths of a gallon.

So if he swapped to this one he'd get greater usage accuracy? 

EDIT

Looking at it again, I guess the sensor only picks up one full revolution at a time so the dial it's on equates to 1 pulse per gallon where as the one to the left will equal one tenth of a gallon per pulse (or 0.378541 Litre).
« Last Edit: February 14, 2018, 08:57:55 am by jack-daniels »
 

Offline fourtytwo42

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Re: Pulse output from a water meter (mechanical question)
« Reply #7 on: February 14, 2018, 08:27:32 am »
Following your sugestion and moving the magnet dial to say 100's would mean my reading reselution would drop to 100 Litres and I cannot figure why I would want to do that  :-//

I think the dial the sensor is on is tenths of a gallon and the dial to the left is hundredths of a gallon.

So if he swooped to this one he'd get greater usage accuracy? 

EDIT

Looking at it again, I guess the sensor only picks up one full revolution at a time so the dial it's on equates to 1 pulse per gallon where as the one to the left will equal one tenth of a gallon per pulse (or 0.378541 Litre).

Ahhhh  :phew: now I understand what I missed in the question thank you :)
 


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