Hello

I know this is an old post but I do water meter monitoring using the inbuilt magnet on the meter dial pointer and a Hall sensor.

Now and again, I get a train of pulses which I believe is due to mechanical jitter on the dial pointer.

In the Falcon data sheet, they talk about damping vibrations using the three coils.

Am I right in thinking that they are talking about mechanical damping?

I think that with water meters involving all the gear trains and subsequent potential slack in the system, on start up by running the tap etc., the pointer does not move off cleanly and may pass several times though the Hall sensor pickup area.


Mod: link to old thread.
https://forum.allaboutcircuits.com/...-the-lc-loop-in-the-meter.180653/post-1689413

 

The thread you refer too concerns inductive sensing of meters not fitted with magnets and the damping effect of the metal slug/coil in the meter pointer on an induced oscillation in a nearby coil, nothing whatever to do with mechanical damping.

I too used to have a meter with a magnet pointer that I sensed with a reed switch, I had a de-bounce filter in software and I suspect you need the same as the pointer moves very slowly so remains in the transition zone for a long time (it may even stop there). You don't say if your hall sensor is analogue or digital but it may also lack sufficient hysteresis.

 

The thread you refer too concerns inductive sensing of meters not fitted with magnets and the damping effect of the metal slug/coil in the meter pointer on an induced oscillation in a nearby coil, nothing whatever to do with mechanical damping.

I too used to have a meter with a magnet pointer that I sensed with a reed switch, I had a de-bounce filter in software and I suspect you need the same as the pointer moves very slowly so remains in the transition zone for a long time (it may even stop there). You don't say if your hall sensor is analogue or digital but it may also lack sufficient hysteresis.

Indeed, different technology here.
And indeed, the hysteresis is the biggest thing here, where sometimes the pointer ends at exactly the tipping point in between one reading and the other.

My meter as described is not too bad (so I did not bother fixing it yet) but it does get hit with these extra readings because the hysteresis and readout reliability are not compatible.
If ever I bother testing the counter-chip, I hope that will be a thing from the past.

 

If ever I bother testing the counter-chip, I hope that will be a thing from the past.

Hahaha but that was 2019!! I guess you are a very very busy person
I looked at the pulse inductive method as the wretched water company has now fitted one of these meters to my house too but concluded the SNR just wasn't good enough & to much electronics down the hole.
Instead I am going for reflective IR working on the difference between the red plastic and the white background, again the SNR is not great but IMOP better than pulse inductive. My meter is well out of WIFI range so almost certainly a cable to the house, waiting for when I hire a Kango for other things to cut a slot across a concrete path for it.
Why they had to change from the magnetic pointer I cannot fathom, some rubbish about enhanced anti-tamper protection, just makes everything more complex & expensive. They should not be allowed to install these things w/o customer remote reading facilities, there is apparently a "smart" version being installed experimentally in some favored areas (London?), so unlikely to ever reach me, I asked about it & got a big NO.