alias tag

[RAHIB HASHIM]

i'm migrating rs logix 500 ladder logic to 5000.
please tell me how to configure the following tags in 5000
N[N100:27]:37
N122:[N128:2]
N[N200:0]:[N200:2]?

 

[daba]

I would probably do this with a two-dimensional array for the N tag, and use DINT tags File and Word to address the elements.

eg. N[File,Word]

I would of course assess the implications of memory usage... for example if my RSlogix 500 project had its indirectly addressed N tables starting at N100, and I had, say, 20 of them, I would manipulate the File pointer so that it was reduced to 0, so that the bottom 100 "File" areas of my array tag were not wasted. You would either need additional code to restrict the File pointer, or you could address the elements using expressions in the brackets.

eg. N[File-100,Word]

My N tag would then be configured as N[20,xxx]

Your examples.....

N[N100:27]:37 MOV N100[27] File : MOV 37 Word
N122:[N128:2] MOV 122 File : MOV N128[2] Word100,Word]
N[N200:0]:[N200:2] MOV N200[0] File : MOV N200[2] Word

N[File-100,Word] would address all of those....

 

[RAHIB HASHIM]

i just made an array with a tag name 'N',then i created two array
and i assigned N[N100_27,37] in move instruction.it is showing no error now,
please confirm with the expression what i given is right or wrong?

 

[daba]

i just made an array with a tag name 'N',then i created two array
and i assigned N[N100_27,37] in move instruction.it is showing no error now,
please confirm with the expression what i given is right or wrong?

Yes that is good....

I had assumed you had created array tags for N100 ...

eg. N100[xx] instead of individual tags N100_0, N100_1, .... N100_27 ....

either way works, but my method would have used much less memory, since there's an overhead for each tag in the database.

Say you had 100 x N100's (N100_0 to N100_99), that's 100 tags, each with their own overhead.

If N100 was an array tag, however (N100[100]), then that is only 1 tag.

ideally you would want N[N100[27],37], but that is not allowed - you cannot "nest" the square brackets, which is why I did the MOVs above.

 

[RAHIB HASHIM]

Thank you sir for the reply.
i have one more issue when i downloaded the program.
Fault is occured:
(Type 04) Program Fault (can be trapped by a fault routine)
(Code 20) Array subscript too large, or CONTROL data type POS or LEN invalid.
Please give me any input's to overcome this?

 

[daba]

I would say that one of your index values is pointing to an array element that doesn't exist.