Smax function for shaft relative vibrations measurement

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pannonius
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Posts: 1
Joined: Sat Oct 29, 2016 1:40 pm

Smax function for shaft relative vibrations measurement

Post by pannonius »

Hi!

I want to achieve measurement of Spp,max function, which is defined as Spp,max=sqrt(App^2+Bpp^2),where App and Bpp are the peak-to-peak values of time domain signals from input A and B, respectively.
I have a problem to obtain that measurement formula as sqrt((peak(A))^2+(peak(B))^2), but the "Next" button remains grayed out, so it is obvious that I have an error in that formula.

I would like to ask You to help me "construct" this formula!

Yours,

Josip
Martyn
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Re: Smax function for shaft relative vibrations measurement

Post by Martyn »

The mathematical processing behind the scenes does not allow the use of the peak function twice in the equation, which is why it remains red and you can't select next. I will start a discussion with the team as to whether it would be possible to change this.

In the meantime you could try replacing one of the peaks with (max - min) and see if that gives the results you need.

sqrt((peak(A))^2+(max(B)-min(B))^2)
Martyn
Technical Support Manager
pannonius
Newbie
Posts: 1
Joined: Sat Oct 29, 2016 1:40 pm

Re: Smax function for shaft relative vibrations measurement

Post by pannonius »

Hello Martyn,

Thank You for Your reply.
So, As I found my initial idea is not viable, I tried the formula sqrt((max(A)-min(A))^2+(max(B)-min(B))^2) and also sqrt((max(A)-min(A))*(max(A)-min(A))+(max(B)-min(B))*(max(B)-min(B))). The software allows this formula, but gives the wrong value. For (max(A)-min(A))=573,376 and (max(B)-min(B))=608,0339, Smax gives a value of 75.032,1, which value is incorrect (obviously).

With regards,

Josip
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Erroneous formula 02.jpg
Erroneous formula 01.jpg
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