Long Term Current Clamp Measurement

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ashtray1987
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Long Term Current Clamp Measurement

Post by ashtray1987 »

Hi Guys,

Wondered if any of you have had to perform long term measurements with a current clamp and run into battery life issues?

How have you worked around the battery life of the current clamps? Do you provide an external power supply?
Can the current clamps accept a 12V supply?

I see only around a day of recording with a standard 9V battery.

Reason being I want to use the PicoLog software with a 4425 and Current Clamp for long term quiescent current measurements over several days (possibly weeks)...

I'm aware that Pico has, shall we say a way to avoid this issue coming, but I just want to discuss existing technology for now.

Thank you
Ashley

liviu2004
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Re: Long Term Current Clamp Measurement

Post by liviu2004 »

Days? I’m glad that the current clamps won’t drift for 30m, can you imagine in days?

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PicoKev
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Re: Long Term Current Clamp Measurement

Post by PicoKev »

Two options.......

Either start saving and wait or just use an external power supply instead of the 9V battery. You will however still have the inherent drift issue in an inductive clamp of any make or model which has been explained on here several times before. :D

ben.martins
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Re: Long Term Current Clamp Measurement

Post by ben.martins »

Hi Ashtray,

The better solution for this type of measurement in my opinion is the resistor method (parasitic drain measurements) and monitoring the voltage drop. PicoLog6 includes math functions that will allow you to graph the measurement as a current as well but please be aware that PicoLog will sample interval of 1ms as the fastest speed. However, this will allow you to measure over a period of days/weeks/months should you wish.

All current clamps will drift over time, maybe if you were able to provide an external power supply to the clamp and then not press the Zero button but use the Zero offset in the software. More on this can be found here - https://www.picoauto.com/library/training/parasitic-drain

Hope this helps and please let us know how you get on.

Kind regards

Ben

ashtray1987
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Re: Long Term Current Clamp Measurement

Post by ashtray1987 »

Hello Ben,

Thanks for the feedback, I had tried a method of using the battery sensor as a current shunt but unfortunately the resistance is just too small for their to be significant amount of voltage drop when doing quiescent measurements (at least within the picoscopes min voltage ranges). It does however work great for higher draw stuff like relative compression though.

Do you by any chance know if the current clamps can handle 12v? Otherwise a bench power supply is gonna be a pretty expensive route.

Cheers
Ash

liviu2004
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Re: Long Term Current Clamp Measurement

Post by liviu2004 »

An electrical equipment which can take 33% more input voltage without damage must be a state of the art product.
Wasn’t 12.5 at the battery? Thus almost 40% more voltage input? I already see the smoke coming out ...

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PicoKev
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Re: Long Term Current Clamp Measurement

Post by PicoKev »

"Otherwise a bench power supply is gonna be a pretty expensive route."
Not at less than £25 + VAT it isn't. :roll: Link to CPC website

stevieturbo
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Re: Long Term Current Clamp Measurement

Post by stevieturbo »

Or a cheap voltage regulator from say 12v down to 9v ?

Plenty of very cheap power supplies available for 9v etc

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