Look-up code on DB that consist of data string

huggy_d1

layudhi

Hii All,
I'm looking reference on programing in TIA Portal V11#sp2

I'm developing a program that can check if input data string have been registered on Data Block that act as Database.
Input Data String have to be compared to each member of Database DB
My problem are :
1. Is it posible to use built-in TIA Compare block to compare String ?
2. Because there is no indirect addressing on TIA Portal, is there any alternative methode to check entire DB without make it one by one as much as Data Block member ?

With SCL, and maybe s7-1200??? you can use peek/poke to go through the DB, but structuring your DB as an array of string makes it easy to loop through the strings.

If you want faster DB searching, how about adding a hash function to compare test string with existing strings, or an index that searches integers relating to the strings and search the array of integers.

How many strings are you potentially searching? 10? Just loop. 1000, find alternate methods like hash functions or perhaps insert into a sorted array making ita binary search to get to the test string.

There is indirect addressing in portal.

huggy_d1

layudhi

huggy_d1

layudhi

Hii All,
I'm looking reference on programing in TIA Portal V11#sp2

I'm developing a program that can check if input data string have been registered on Data Block that act as Database.
Input Data String have to be compared to each member of Database DB
My problem are :
1. Is it posible to use built-in TIA Compare block to compare String ?
2. Because there is no indirect addressing on TIA Portal, is there any alternative methode to check entire DB without make it one by one as much as Data Block member ?

With SCL, and maybe s7-1200??? you can use peek/poke to go through the DB, but structuring your DB as an array of string makes it easy to loop through the strings.

If you want faster DB searching, how about adding a hash function to compare test string with existing strings, or an index that searches integers relating to the strings and search the array of integers.

How many strings are you potentially searching? 10? Just loop. 1000, find alternate methods like hash functions or perhaps insert into a sorted array making ita binary search to get to the test string.

There is indirect addressing in portal.

Hi Huggy_d1
Thanks for the reply

Could you please more detail about your explanation above ?

The Database DB can consist up to 200 data String

Regards,
Layudhi

hash function: http://en.wikipedia.org/wiki/Hash_function
S7-1200 Peek/Poke look in instructions on how to access them for DBs to do indirect addressing.
To set up an array of string, I would suggest using the max length your strings will use rather than the default 254. Will speed up searching and save storage.
SCL can loop through an array very easily to capture the stored string.

huggy_d1

The f1 help for me showed how

Peek_int(...)

Peek_char(..)

And so on