How do you replicate a ladder FSC inst. in structured text for SFC application?

[cafein 0]

Hi! I'm writing a program in RS Logix 5000 for a Contrologix in SFC and I'd like to use as much structured text as possible and keep ladder routines as low as I can. I have to look trough an array of DINT (40) for a specific number and return the position in the array where that number is. I know I can do it through a ladder routine with a FSC instruction but I would rather replicate the fonction in structured text in the SFC routine. Any tips appreciated :) -Olivier /Edit P.S. First Post Edited 8 Jul 2013 by cafein

[RussB 22]

A couple of tips. 1. Review all of the ST Functions & commands and read how they work. 2. Verify that the ST functions you want to use work as you think they do, experiment. 3. Use ST as your "specific" or called routines that are used many times and keep LD as your main control program logic. (Those needing to troubleshoot your system will thank you.)

[cafein 0]

Hi, thank you for your time. I am programming the entire process in Sequential Function Chart (SFC) so the logic is pretty straight forward and easy to troubleshoot. I love SFC for that. The sequence is pretty simple so it's easy to follow. Plus, I'm a serial commenter :)

[RH- 1]

Hello, if I'm understand well, you can just create a loop with indirect addressing (DINT have to be in array) something like this: index:=0; i:=0; FOR i:=0 TO 39 BY 1 DO IF array[index]=inumber_to_compare THEN index:=target_pos ; END_IF; index:=index+1; END_FOR; For sure it's just a base and I am not programming in structure text very often so... test it.

[cafein 0]

Hi RH-! That looks like it should work. Should I place an EXIT after line 7 or 8 if I want to return only the first one found? Guess I need to test it. Thank you very much sir.

[RH- 1]

; Ok, if you want to finish, when you find your number, I think this will works fine: index:=0; i:=0; FOR i:=0 TO 39 BY 1 DO IF array[index]=number_to_compare THEN index:=target_pos ; i:=39 END_IF; index:=index+1; END_FOR; You are more than welcome, Radek

[cafein 0]

Thanks again Radek. Let's say I wanted to repeat that function 6 times to 6 different arrays. Can I put a FOR loop inside a FOR loop? Also, will it scan array[0] Edited 10 Jul 2013 by cafein

[RH- 1]

Hello, I don't know your all requests but, this will might works too, but you can, at the start, just copy it. I will avoid to have multiple loop at the start when your code is growing, because afterwards is sometimes problem to find your mistakes. (*Field search 1*) index:=0; i:=0; FOR i:=0 TO 39 BY 1 DO IF array1[index]=number_to_compare1 THEN index:=target1_pos ; i:=39; END_IF; index:=index+1; END_FOR; (*Field search 2*) index:=0; i:=0; FOR i:=0 TO 39 BY 1 DO IF array2[index]=number_to_compare2 THEN index:=target2_pos ; i:=39; END_IF; index:=index+1; END_FOR; (*Field search 3*) index:=0; i:=0; FOR i:=0 TO 39 BY 1 DO IF array3[index]=number_to_compare3 THEN index:=target3_pos ; i:=39; END_IF; index:=index+1; END_FOR; (*Field search 4*) index:=0; i:=0; FOR i:=0 TO 39 BY 1 DO IF array4[index]=number_to_compare4 THEN index:=target4_pos ; i:=39; END_IF; index:=index+1; END_FOR; I should browse array[0] as well because index is set to 0 at the start of function.

[cafein 0]

Hi, I was wrong on last post. WHat I actually need to to is compare 6 different values to that same array. Those 6 values themselves are arranged in an array. Here's what I came up with. index1:=0; i1:=0; FOR i1:=0 TO 5 BY 1 DO index2:=0; i2:=0; FOR i2:=0 TO 39 BY 1 DO IF array[index2]=number_to_compare[index1] THEN index2:=target_pos[index1] ; i2:=39; END_IF; index2:=index2+1; END_FOR; index1=index1+1; END_FOR;

[RH- 1]

Ah, OK, I think that this gonna work. Good. :o)