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PicoScope 4424 Phase Angle Measurements

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PicoScope 4424 Phase Angle Measurements

Postby mawo » Mon Aug 29, 2011 10:51 am

I´m using the PicoScope 4424 and I wonder if there is a hidden possibility to measure the phase angle between two signals. I´ve tried to build my own phase angle software with the development kit but unfortunatly I do not have such great experience in programming.

I have used the search function of the forum but all it says is that the feature maybe implemented at a later time (post from december). I really need this function asap...
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Re: PicoScope 4424 Phase Angle Measurements

Postby aarne » Tue Aug 30, 2011 1:26 pm

Beta software Maths Channels? ---> acos(integral(A*B)/(sqrt(integral(A*A))*sqrt(integral(B*B))))/Pi*180
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Re: PicoScope 4424 Phase Angle Measurements

Postby Martyn » Wed Aug 31, 2011 11:55 am

Thank you for the equation, I have given it a go and it works reasonably well although there are some issues at the start of the trace due to the unknown start conditions. We have found that by applying a DC average measurement on the Phase Maths Channel, selecting the range to "between rulers" and then adjusting them it is possible to achieve a reasonable result.

If you have any other interesting scenarios then please let us know, we may be able to reward good contributions.
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Re: PicoScope 4424 Phase Angle Measurements

Postby mawo » Thu Sep 01, 2011 3:22 pm

Thanks for your reply I´ll try this right now.
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Re: PicoScope 4424 Phase Angle Measurements

Postby mawo » Thu Sep 01, 2011 3:52 pm

And it works! I hope you´ll implement it as a fixed measurement for the next release.
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Re: PicoScope 4424 Phase Angle Measurements

Postby aarne » Fri Sep 02, 2011 5:43 am

Active power P=Urms*Irms*cosφ
Power factor cosφ=integral(A*B)/(sqrt(integral(A*A))*sqrt(integral(B*B)))
φ=acos(integral(A*B)/(sqrt(integral(A*A))*sqrt(integral(B*B)))) [rad]
φ=acos(integral(A*B)/(sqrt(integral(A*A))*sqrt(integral(B*B))))/Pi*180 [deg]

I have in mind this phase angle.
Measurement time should be “reasonably long”.
 
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Re: PicoScope 4424 Phase Angle Measurements

Postby johndyer » Tue Dec 09, 2014 8:18 am

Thanks for the phase angle equation; this gets me dangerously close to what I need. Can anyone think of a way to measure the phase angle between a squarewave and a sinewave? (I tried that equation and it doesn't seem to like the square wave). Here's my situation: I have a motor that generates sinusoidal voltage. The motor uses hall sensors for position feedback and I'm trying to mechanically time the hall sensor to the motor voltage. I need something to measure the phase angle real time so that I can physically adjust the position of the hall sensor while watching the oscilloscope. On my tektronix scope there is a math function that calculates the phase angle just fine; I'm just really hoping to use the Pico instead.
Thanks!
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Re: PicoScope 4424 Phase Angle Measurements

Postby Martyn » Mon Dec 15, 2014 1:24 pm

I have tried in the demo software and the relationship looks to be OK. I was working from the zero crossing points of the sine wave and then looking at the phase relationship of the edges of the square wave.

BTW dragging in the two bottom right hand cursors on the display, green circles, gives phase rulers and then using the normal time cursors you get phase reported in the cursors measurements box as well.
Attachments
example.psdata
Phase maths channel and rulers
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