Unity Pro ANY_ARRAY Base Index

[Schnider]

Hi,

Unity has the option to index its arrays between any two numbers; e.g. "ARRAY[13..27] OF INT".

I am writing a DFB which needs to take in a variable size array. Does anyone know how to determine the base (lowest value in array) of an ANY_ARRAY, or if there are some tricks to addressing the array without getting an overflow error? I am aware of "LENGTH()" to determine the length of the array.

FYI, this is Unity v13.1 with an M580.

Cheers

 

[Lare]

You can use EXTRACT block, it uses zero based addressing for input.
Extract your array to fixed array lenght, and then compare from position 0 or 1 on new array with lenght?

 

[Schnider]

Lare - Thank you, this is perfect!

 

[Lare]

With extract you need to remember that it uses bytes for copying so lenght is 2x array for block (for integers). Extract block gives easily error and data is not copied if parameters are wrong)


Both start and destination positions are now 0.


Input and output arrays don't need to be same lenght.



You can build your own DFB block, then inside block use extract block and locate you input array (original data) to new fixed lenght (like 0.999) or something.
(You can even locate your temp array to output of block (any array type, so you can save little bit memory as you can only make temp variable as long as you need every time, but whit M580 memory won't be prolem like P57 series.)


There is old thread of extract:


http://www.plctalk.net/qanda/showthread.php?t=85103