Siemens fc10 to compare 2 strings

[Stanley_Smith]

Hi,

I'm scanning a code from each box to compare and see if the box scanned is a "good" box. The whole code is about 21 bytes and I only want to compare 9 bytes since those 9 bytes differentiate between the 2 types of box. I created (2) 9-byte strings in DB98, string1[9] starts at 0.0 and string2[9] starts at 12.00.
I entered 9 "good" characters in the initial value column for string2. String 1's value will be read from the scanner. FC10 is used to compare the two strings. The problem is that the results are always equal(true) doesn't matter which boxes was scanned ! In the VAT table, string2's first character which is 0 actually starts at db98.dbb 14, not 12. According to Siemens help file, the first byte in a string is to show maximum length of the string, the second byte shows the actual string length. HELP ! is there any suggestion on how to correctly solve my problem? Thank you

 

[berkeman]

Since nobody has replied yet, I'm guessing that none of us are familiar with the system and tools that you are using. I'd still like to help, so if you can provide a pointer or explain what DB98, FC10, VAT, etc. pertain to, perhaps I can be of help.

 

[ravenprp]

for reaching out and sharing your issue with comparing two strings using Siemens FC10.

Firstly, it is important to note that the FC10 function block is used for comparing two operands, not two strings. In order to compare two strings, you will need to use the FC11 function block.

In your case, you have created two 9-byte strings in DB98, but you are only comparing the first 9 bytes of each string. This means that the remaining bytes in the strings are not being compared and could be causing the issue with your results always being equal.

To correctly solve your problem, you will need to use the FC11 function block and compare the entire strings instead of just the first 9 bytes. Additionally, make sure that the initial values you have entered for string2 are correct and in the correct format for comparison.

It is also worth checking the data types of your operands and ensuring they are compatible for comparison. If you continue to experience issues, consulting the Siemens help file or reaching out to their customer support for further assistance may be helpful. Best of luck with your project!