RSLogix 5000 Copy Partial Strings

[Bolatov]

Hello guys Im having one trouble when copying partial strings

I use an index variable but im loosing the first 4 charaters of the string


COP
String_Check.DATA[Variable]
Information
1

Here is the string content:

String_Check
02310061 1 010000020003 04 050006005070000080000091101111120013001300190014001600150015021600015170999918000001902888202014-11-14:11:01:43212014-03-04:08:15:13222230000379921$


Information
0061 1 010000020003 04 050006005070000080000091101111120013001300190014001600150015021600015170999918000001902888202014-11-14:11:01:43212014-03

I tried to copy also like this but it doesn't works

COP
String_Check.DATA[Variable]
Information.DATA[0]
1

I have made it work with:
COP
String_Check.DATA[Variable-4]
Information
1
but if the variable equals zero the plc is faulted

thanks a lot for your help

 

[OkiePC]

Try the MID instruction. It is built for the purpose. I believe the string length is stored at the beginning of the data representing the string (that is how it works in older A/B controllers) Then each character only takes one byte, so that may explain why four bytes (one DINT) seem to disappear since they may be used in a likewise fashion to track string length.

 

[Bolatov]

thanks for the fast response, let me give you more details

actually Im receiving a data string from an equipment
this string has some values that I need, but they are not always in the same position, so I had to do a search to find the index of the string where these values are, but when I copy them to another string I loosing that information

I cant use MID because the position has variation