The suggestion here is most definitely not to tamper with the meter (meaning break seals or open the case in any way) most meters are built so that you can pick up the integrated units via the/an indicator. They do this because as soon as you break the seals on the meter you are in breach of your contacts and the makers warranted calibration is null and void. But in many cases (utility smart metering, building management etc) there is a legitimate need to count what you have used without affecting the measurement. Utilities are required to be able to show that they have not tampered with the meter so as to fiddle the customer, meters are calibrated and sealed by the manufacturer for this reason.
There are 3 types that I know of (Some no longer used with the move to smart metering)
Optical, an LED blinks once per unit of consumption or an indicator changes state such that you can use a reflective opto-coupler to pick up signal.
Magnetic, the field changes per unit of consumption such that you can use a hall effect switch or reed switch to pick up the signal.
Dry Contacts, there is a little pair of holes in a plastic plug that you can plug a pair of wires into the circuit is made/broken once per unit of consumption such that you can pick up the signal.
All of the above allow passive monitoring of your meter and by extension consumption without voiding waranties, calibration or contracts.
optical (it also does bi direction serial with the meter if you know how) is very common with the modern range of electricity meters, the ones that blink an led at you. Look carefully next to the LED is a photo cell so with the correct attachment you can talk to the meter…. If you have the correct software and passwords etc. Just monitoring the LED pulse though without attempting anything else though is quite safe.
Magnetic is anything but popular with electricity metering for obvious reasons.
I have seen black/silver reflective disks indicator types and dry contact types in gas meters.
Water I have yet to have a play with. I avoid messing with ours in case some kid on a bike runs over me lying prone in the middle of our pavement. (Rather embarrassing, lol) I can imagine that the dry contact method is least likely to be used here again for obvious reasons.
As water and gas are metered without the use of electricity (purely mechanical) most don’t have any electronic capability at all.
As you can see from the manufacturers docs for your meter the electronic reading package just clips on the top of the outside and picks up the change of the indicator.
When you work out for sure how to pull a signal off your water meter (without tampering) please do come back and tell me…… I would love to know.
