Trapezoidal Integration of Rogowski Coil Signal

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Brandon
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Joined: Wed Jan 02, 2019 11:48 am

Trapezoidal Integration of Rogowski Coil Signal

Post by Brandon » Mon Jan 07, 2019 3:27 pm

We are monitoring the raw Rogowski coil signal on an DC transformer (used in resistance welding). Typically, a hardware integrator circuit is used to produce the integrated value of the signal. But we would like to use the PicoScope software to perform this integration if possible.

One issue we have encountered is that because we are monitoring a PWM source, and want to integrate only during the "ON" portion, and ignore the "OFF" time. This means a simple integration formula would not be adequate.

Ultimately what we have seen is that we could use trapezoidal integration, but can that be done in real time with the software?

Does anyone have any advice or experience with such measurement and calculation?

Thanks in advance for your help!

Gerry
PICO STAFF
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Joined: Mon Aug 11, 2014 11:14 am

Re: Trapezoidal Integration of Rogowski Coil Signal

Post by Gerry » Wed Jan 09, 2019 11:29 am

Hi Brandon,

Unfortunately you can't perform Math functions on data in real-time, because the software needs a collected buffer of data to work on, and you can't accumulate data between successive buffers.

Could I ask why you need to see the integrated result in real-time?

For the record, to view the integrated data after capturing the data you can use a Math Channel to create a level filter (setting everything below a certain level, e.g. the OFF period of the PWM, to zero) so that when you apply an integral to the signal, only the ON periods add to the result. I have created an example below that will integrate everything above 0.5V:

Example integration for on periods only.psdata
(631.13 KiB) Downloaded 31 times

Regards,

Gerry
Gerry
Technical Specialist

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