Turnigy Wattmeter clock does not work with less than 1 amp

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SamTexas   100 MW

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Turnigy Wattmeter clock does not work with less than 1 amp

Post by SamTexas » Dec 23 2012 12:00pm

In case you guys don't already know.

The clock (elapsed time) does not get updated if the current is less than 1A. At least not on my brand new unit.

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Re: Turnigy Wattmeter clock does not work with less than 1 a

Post by Caliban » Dec 23 2012 4:28pm

Is this not a design feature? Where the intent is just to clock the time when current is being drawn? Mine didn't come with ant documentation either!

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Re: Turnigy Wattmeter clock does not work with less than 1 a

Post by Caliban » Dec 23 2012 4:34pm

Well, mine has the same behaviour/problem!

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Re: Turnigy Wattmeter clock does not work with less than 1 a

Post by SamTexas » Dec 23 2012 4:36pm

I doubt it. Less than 1 amp is still current. The bright side is that the A, V, W, Ah, Wh, Wp and Vm are still being recorded correctly, as far as I can tell. For that to work the internal clock must be running. It's just not getting updated for the display.

Glad to know that yours behaves the same way. I wonder if the manufacturer's is aware of this defect.

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TMaster   1 kW

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Re: Turnigy Wattmeter clock does not work with less than 1 a

Post by TMaster » Dec 23 2012 11:18pm

Here's mine, Running less then 1 Ah; and is shows it and calculates it. My meter is over a few years old though. I also reprogramed a lot of it and modded so it can handle 100V. But i didnt mess with the low and top end of the current calculating. The internal clock as you call it is not very quick on updating. I believe the calculations are measured from a range, and the very low readings and the very high readings are not as accurate as middle readings. Its averaging measurements to get other measurements.

Good thread on the internals and programing:
http://endless-sphere.com/forums/viewto ... =3&t=13607

Video of less then 1 amp:
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Re: Turnigy Wattmeter clock does not work with less than 1 a

Post by amberwolf » Dec 24 2012 1:48am

SamTexas wrote:In case you guys don't already know.

The clock (elapsed time) does not get updated if the current is less than 1A. At least not on my brand new unit.
Clock?

Mine are both at least a couple of years old, and the only clock is whatever internal one they use to count up Ah and Wh. They look just like the one at the beginning of the thread TMaster linked above.

Does this mean the newer versions have a new separate field on the display for elapsed time?


Anyhow--AFAICR mine do log Ah and Wh even when at very low currents, so their internal clocks are running, at least. (although they don't seem to be very accurate at low currents) I'd have to go dig up some of my old posts or rig a test for them to be certain, though--my memory is not great these days, especiallly with my bad teeth throbbing like they are now.

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Jeremy Harris   10 GW

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Re: Turnigy Wattmeter clock does not work with less than 1 a

Post by Jeremy Harris » Dec 24 2012 4:09am

SamTexas wrote:I doubt it. Less than 1 amp is still current. The bright side is that the A, V, W, Ah, Wh, Wp and Vm are still being recorded correctly, as far as I can tell. For that to work the internal clock must be running. It's just not getting updated for the display.

Glad to know that yours behaves the same way. I wonder if the manufacturer's is aware of this defect.
It's designed in. I had to do the same with my home brew one, albeit with a lower current threshold. The reason has to do with the maximum resolution available on the analogue to digital converters in the µcontroller used. The majority of small µcontrollers have a 10 bit resolution, with the one in this meter having the ability to add 20x gain at the front end. These meters use a 1mohm shunt and an internal reference that's normally around 2.5V, so 1 bit = 0.000012 V or thereabouts. This is in the region where random noise dominates the signal at low current levels, and noise on the current input would make the meter record Ah when zero current was flowing (these meters are unidirectional, so cannot subtract current to even things out). The fix is to have a current threshold below which the Ah counter stops. In the case of the cheap Turnigy they've selected a value of around 1A, probably on the basis that this is OK for a meter that's intended for high current use by the RC crowd.
Please ask questions on the forum, rather than by PM, as it helps others and you'll get a better range of answers.

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Re: Turnigy Wattmeter clock does not work with less than 1 a

Post by SamTexas » Dec 24 2012 6:54am

amberwolf wrote: Mine are both at least a couple of years old, and the only clock is whatever internal one they use to count up Ah and Wh. They look just like the one at the beginning of the thread TMaster linked above.

Does this mean the newer versions have a new separate field on the display for elapsed time?
Mine has a field for elapsed time which is displayed on the lower left corner along with Ap, Wp, Vm.

Anyway, regardless of inner working limitation it's still a defect. The least they could do is to document it.

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Jeremy Harris   10 GW

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Re: Turnigy Wattmeter clock does not work with less than 1 a

Post by Jeremy Harris » Dec 24 2012 7:13am

SamTexas wrote:Anyway, regardless of inner working limitation it's still a defect. The least they could do is to document it.
Defect implies that the product is faulty. The reality is that it's a product design limitation.

I agree that documentation would be good, but I've yet to see decent and accurate documentation (or often any documentation) with most of this cheap Far Eastern made stuff.
Please ask questions on the forum, rather than by PM, as it helps others and you'll get a better range of answers.

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