I am using PicoScope 6 with 4262.

As shown in the picture, the real-time AC RMS measurement result is 1.331mV, while the AC RMS of the same waveform saved as psdata is 3.514mV. I also save data as .csv and calculate with excel. The result is also 3.514mV, the same as the one saved as psdata. So is the real-time AC RMS measurement incorrect?

## AC RMS difference of Real-time and psdata saved

### Re: AC RMS difference of Real-time and psdata saved

Taht is because the realtime RMS was calucated over the last 20 captures.

capture count colum.

The saved value shows 1

The realtime value shows 20.

Benno

capture count colum.

The saved value shows 1

The realtime value shows 20.

Benno

### Re: AC RMS difference of Real-time and psdata saved

I use save all psdata, which contain 15 waveforms. The AC RMS of each waveform is the almost the same, which is about twice of the real-time AC rms. And the signal I give is constant, the real-time AC RMS also change only slightly over the time.bennog wrote:Taht is because the realtime RMS was calucated over the last 20 captures.

capture count colum.

The saved value shows 1

The realtime value shows 20.

Benno

So can you explain why the real-time AC RMS value calculated over the last 20 captures is only about half the saved value?

Best Regards,

Yu-Meng

### Re: AC RMS difference of Real-time and psdata saved

Can you post the actual psdata files so we can take a look.

Martyn

Technical Support Manager

Technical Support Manager

### Re: AC RMS difference of Real-time and psdata saved

The psdata files are too big, The maximum allowed size is 512 KiB. Can you give me your email address? So i can send you the psdata files.Martyn wrote:Can you post the actual psdata files so we can take a look.

### Re: AC RMS difference of Real-time and psdata saved

The email address is support@picotech.com if you just use Save Current Waveform it will help to keep the size down

Martyn

Technical Support Manager

Technical Support Manager

### Re: AC RMS difference of Real-time and psdata saved

I have sent the psdata files via email.Martyn wrote:The email address is support@picotech.com if you just use Save Current Waveform it will help to keep the size down

The size of the save current waveform is also 1061KB.

You can see from the save all waveforms file that the AC RMSs of all 15 waveforms are nearly the same.