Degree of accuracy in Trend object

Sharer
2009-09-30
2010-02-02
  • Sharer - 2009-09-30

    For Trending, CoDeSys demands: [Degree of accuracy] > 50 msec. This is probably because the visualization task (VISU_TASK?) spends a corresponding amount of time, and the worst-case timevalue is visible internaly to CoDeSys, which therefor limits accordingly ? In this case, is it possible to override this limitation (assuming that the real execution time for the visualization is significantly lower than 50 msec) ?

     
  • shooter - 2009-11-10

    make a table when needed faster because trend is very slow, and not supported.

    the trend has lots of software around it and is in the plc also slow.

     
  • Sharer - 2009-11-11

    Thank you very much for your response!

    A table/array allows me to store each sample, yet how can I visualize the samples as a trend (without using the built-in CoDeSys Trend object) ? Do I have to forward the samples table/array via the fieldbus and then visualize the trend on the connected computer ?

     
  • shooter - 2010-02-02

    do the trending yourself so with a pointer where it should write new data and a pointer where you took data.

    so program something like

    position a is added 1

    put variable on place a in array

    when array full start over again.

    when showing start at a and then till end, then start from zero until a that makes the circle round again.

    it is lot faster as to shift all data one place every time.

     

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