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Measuring velocity by comparing postion values in DIAdem

Hi there,

I'd like to measure the velocity of a moving hydraulic cylinder. I have the position value available as an analog value (0-10V or 0-200mm), acquired with a pci board and DIAdem DAC. How can I accomplish this in DIAdem? My idea was to subtract two consecutive position values and divide the result by 1/(sample rate). This value I want to display online while the cylinder still moves, so the equation of v has to be done in some way in the DAC module. How can I extract a set of consecutive values to perform that operation?

Any ideas?

Thanks in advance

Regards
Achim
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Hi Achim,

i think you´re using the standard DAC-Mode (not Paket-Mode).
In this case the "signalcopy-block" may solve your problem. You can use this functionality to "store" one value for one or more samples.
To get the velocity you have to connect the signalcopy with the same clock than the "formula-block", using a delay of 1. Now both samples are available to subtract.

I hope my added little example will help you.

CU

Martin
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Hi Martin,

thanks for your example, though in the meantime I have found the exact same solution by myself 😉 ! Anyway, it is always pretty nice to get some support!

Perhaps you can provide me with some examples for the usage of the script dac driver block!? I'm trying to get those functions (SFD_...) work, but I don't have a clue about it at all...I'm trying to stop an analog output (reset to 0 volts) when a certain window condition occurs. Unfortunately there a no examples shipped with DIAdem, at least I haven't found any...

Regards
Achim
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Hi Achim,

i don´t know what´s happened with the "Tools"-Folder on the DIAdem9.0 CD.
If you have still a CD DIAdem 8, all you need can be found at "Tools".
If not, i´ve added this folder as ZIP-File.

By the way, where are you from (Germany, ...)?


CU

Martin
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Yes, I'm from Germany, but I thought it useful to keep this discussion in english so that other users will not become confused...

Thanks for the attached file, obviously those examples are not included in version 9.x

so much for now, perhaps you will hear from me again!

Greetings
Achim
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