Compare array of char STEP 5.x

Hello Experts,

I'm trying to program a compare routine for a 32 bytes array, basically the array is being populated correctly but I need to do some crosscheck inside my logic, so I have to compare 2 different arrays. ( of course same structure arrays)

I read some information in the forum but most of them are dedicated to TIA portal which have better tools than mine S7 v5.6.

Does anybody has some tips to help me on this matter? would be the SCL the best language to be chosen?

If any example available to help me think out of the box would be great.

Thank you in Advanced.

silva_SPS

Hello Experts,

I'm trying to program a compare routine for a 32 bytes array, basically the array is being populated correctly but I need to do some crosscheck inside my logic, so I have to compare 2 different arrays. ( of course same structure arrays)

I read some information in the forum but most of them are dedicated to TIA portal which have better tools than mine S7 v5.6.

Does anybody has some tips to help me on this matter? would be the SCL the best language to be chosen?

If any example available to help me think out of the box would be great.

Thank you in Advanced.

The " EQ_STRNG" (FC10) instruction is available in the IEC function library. This can be used if that array of characters where a String type.

Else stepping through the 32 elements is easiest done using SCL. In SCL it is possible to address the array tag with a variable index. Also the For-loop makes it easy to pace through the elements.

Using STL is possible but you need to work harder to do the same with indirect addressing.

Do these notes help you already?

Hello Qwazee,

Thank you for your comments, much appreciated.

The FC10 do not meet my needs, my array is CHAR type and not STRING, not planning on converting it.

Like you said the SCL probably is the best, I will have to learn how to do it since I did not used it much in STEP7.

Would be nice if you have any examples so I can work with that, it would save me time, but of course in the easy or hard way I will have to find a solution.

Thank you again.

You need to recode into Step7 Classic.
The format is the same only the software GUI is different.

The WHILE is more appropriate than the FOR in this case because the loop can be aborted as soon as there is a not equal result.

Interesting, thank you.

I did wrote the code in TIA as you and it seems work fine, recoding to S7 doesn't seems to work since some errors. (attached)

Seems promising tho.

Thank you so much!

FC302: VOID

 ..is the problem.


Mine is:

EQ_ARRAY: BOOL

Tell you what - delete the last code line.

#EQ_ARRAY := #result;

Then find a way to write #result out from the FC. 

The problem was also I wrote the "#" index in Step7 5.4, the variables are wrote direct at the body of the code, so no need "#",

now no more compiling issues, so I can start testing, [snip]

Thank you very much, lot of learning today for me.

New question published by silva_SPS is split to a separate thread with the subject How should declare the array of char in the block input for proper performance?.

Best regards
Jen_Moderator