realization of repetitive rungs in RSLogix ?

Nik

Member
Join Date
Jul 2006
Location
Moscow
Posts
2
Hello people!
My greetings from fas snowy Russia!
I work as a PLC programmer more than a year. I started with Simatic S7, wrote a dozen programms on it. Because that was my first PLC soft, i inherited the most of methods "how to programme something" in step7 style, using Function blocks, Fucntions, structues, and flexible memory area... Now i encountered with such a controller kind as Allen Bradley - SLC (RSLogix500). Interesting controller. And i found its quite differnt from S7. There is no function blocks in RSLogix500? How do you write programms without it, when you need to write many rungs of the same kind?
I wrote the "dummy" rung with variables with symbol descriptions. Then copied it 10 times. Then with Ctrl+H command i tried to replace symbol, for example, "CTP1_ON" to "CTP2_ON". But it cant replace only part in symbol name, it replace the whole symbol variable insted! There is no wildcards when i need to replace symbol name of variable?
 
You can recreate a function block style in AB by using subroutines. You will need to pass the data in and out of it.

Personally, Ive used the VB in RSLogix to write a program that writes the programs. This way it is easy to write 7 identical control zones for example. Sucks to have to make a change this way tho.

Instead of replacing the sybol, replace the variable. For example, when writing repeats, I used different B and N files for each repeat. Then, on the new ladder, find and replace (use LOCAL mode) say B10 with B12 and N11 with N13, and so forth. So, replace B10:?/? with B12:?/? (wildcard). Note this will not replace B10:?/?? with B12:?/??. You will need to do this on a second replace.

matt
 
I've done the same with sub routines.

I have created data areas, which contained variables and pointers to other data areas and passed a pointer to that main data area on entering the sub routine.
 
Thanks for clarifying!
Hm. Compared to Siemens, the methods described above seems not so convenient in use.
For VB i need Visual Basic editor - it goes with Proffesional version. I have only standart.
Whats the difference between the N (Integer) data files and B (Binary) ones? I can use N7:0/0 instead of B3:0/0 and so on. So, i can use whole structure in one data file. Is that correct?

In S7 its possible to create a programm with no accent to variable's address. Its possible due to symbol representation. In AB i should always keep in mind the address?
 
Yea, nothing will prevent you from using the bit call on the N file number. Its more for strong data typing so there is less chance of mix up. But you can use B7:0 or N10:0/0 if you want. I do like to keep them seperate. Floats are seperate tho. They convert to 16 bit and back dynamically in things like ADD and DIV, so you must use the float for floating point. Its really nice being able to say do this

N7:0 * F12:0 = N7:1

without having to convert anything. Unlike the cheap plcs from AD, omron, and others. BCD Must Die! ;) And since when is 16 bit DIV 16 bit = 32Bit??? Arg. None of this is an issue in Logix.

matt
 

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