Use dasylab to find 1.5 percentile and 98.5percentile value of a block

[John.disciullo@andritz.com]

I am using Dasylab 9.0. I need to know the max and min values of a block of data. I have a signal that has a burst of noise coming from my sensor every once in a while so the Max and Min functions of the Statistical Values module are a bit useless for me. Currently, I output the data to excel and I use excel order the data in ascending values and I then remove the first 1.5 % of the points and the last 98.5% of the points and use the 1.5 percentile value as the Min and the 98.5 percentile value as the max. Is there any way to do this in dasylab.

[HeatherBaker]

Hi,

Since you are not addressing any National Instruments hardware, this seems to be DASYlab programming question.  Contacting DASYlab support will probably get you the best assistance.  Have a nice weekend!

[TomRizzo]

John,

I am a litle confused.  Is the a possibility to see your worksheet?

Are you trying to collect an absolute MIN MAX or one per block?

Is the noise spikes bigger than the min max youi are looking to detect but faster?  (You could use filtering for that)

If you could upload the worksheet, we could look into it.

Tom

InSyS Corp.

[John.disciullo@andritz.com]

Hi Tom,

     One of my customers wants me to find one max and on min per block of signal. I am acquiring data at 2000Hz and have a block size of 2048. Since there were some fairly random bursts of noise, I would sometimes get a ridiculously hi max or a ridiculously low min. The customer does not want me to filter anything. So, we came to the agreement to put the data of each block in ascending order and and remove the first 1.5% of the points and remove the last 1.5 % and then perform the max minus min operation. This of course comes out to be the same problem as finding the 1.5 percentile value and the 98.5 percentile value. Would you know of any way to do this. Thank you very much for your time. I would send you my Dasylab worksheet but it just consists of  one input module and then two statistics modules to find the max and the min. I need to replace the max and min however with something that will do what I asked above.

[TomRizzo]

John,

We looked around and we don't think it is possible to do it in DASYLab as it is now.  What you request is not something that is usually done with this kind of applications.

The only possibility at this point is to create your own DASYLab module that would provide this kind of filtering.

Sorry for the bad news

Tom Rizzo

InSyS Corp.

Your DASYLab integrator

[John.disciullo@andritz.com]

I guess I will be stuck using Excel to do some post treatment of the data. Thanks for your time Tom

[TomRizzo]

John,

To create a module to perform that action is not impossible, you just need the developer toolkit and a good knoledge of C.

If you call Measuramnet Computing, they can help you with which product you need.

[MHa]

Hello John,

You can solve this application flexible and very compact with Addon Module "VBScript", sale via PREMEGA GmbH -> link under http://www.premega.de/de-02/software_dasylab_vbscript_de.php

Some screen shots for mainpoints from application:

Global System Variable ${BLOCK_SIZE} inform the VB Script module over the used BlockSize, if Generator used same.



VB Script allow you to save the values into double area -> dim dValue (32768). The samples go into VB Script module step by step. With last incoming you can calculate over the first dValue (0...a) and last dValue (x...y) your min, max, whatever you needs.



Best regards,

MHa