Lookup Table in Codesys 2.3

[WainDude]

Hey everyone, can anyone point me in a direction on setting up a lookup table in Codesys 2.3. I have never done it and it looks like I may have to for a non-linear calculation. I am going to have to enter about 120 data points.

Anyone have any idea on how to do this?

Thanks,

 

[Lare]

do you need change your data points or are them constants all time.

Maybe you can use excel to calculate equation code for data and program equation formula to plc?

http://www.plctalk.net/qanda/showpost.php?p=112953&postcount=26


Or if you want use lookup table, then you only need some 120 different compare rungs or indirect addressing
Basic idea is that you check if your input value is some know point x (or between two x data points) and then you copy known data point y to output.

between two known points you can use formula y=mx+b to better approxmation or then you round y to closest known point

 

[shooter]

yes wain several possibilities

download www.oscat.de (english version library and the pdf belonging to it.
several ways to do your linearization.
1 is make a formula from your database (help can be given, this can be a polynoom, like lare is suggesting)
2 is make a table with x and y and interpolate between the points(this will be linear)
3 do it the fuzzy way