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Volt free pulse measurement

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Volt free pulse measurement

Postby Bobbalus » Wed Feb 15, 2012 11:32 am

I'd like to use one of the Pico USB dataloggers for services meters pulse measuring. These pulses are volt-free but none of the dataloggers mentions this feature. What device, if any, would be best to use?

Thanks. :D
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Re: Volt free pulse measurement

Postby Martyn » Thu Feb 16, 2012 9:52 am

Our loggers require a voltage input therefore you would need a sensor to pick up the signal from the meter and convert it to a voltage. We don't have anything that will do this.
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Re: Volt free pulse measurement

Postby TinWhisker » Thu Feb 16, 2012 10:15 am

Volt-free is, in basic terms, an isolated circuit - you supply the volts! Some people call this 'dry contact'.

The meters pulse is simply relay or opto-isolator switching. As scopes measure voltage and there is none, you will read nothing.
Commonly in gas and electric meters, it'll be a N.O. relay.


You could place a coin battery or AA battery in series to a pulse output:

PulseOutputB------(+)Battery(-)----ScopeGND & ScopeProbe---PulseOutputA

Then you will see a voltage reading of the battery on every pulse!

I found a datasheet on a gas meter to get an idea:

http://www.sontay.com/Datasheets/MG/MG-G.pdf
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