Cyclic program operation in s7-300

mhmtfthnl · Nov 28, 2003

Hi all.I have a question about s7-300 programming.I have written a program in s7-300.But I want to execute the same program again and again when I push to any button that I defined beforehand (program will be started by pushing a button).I am wondering how I can program this function.Namely what program material must I add. (for example label,jump...)In addition, can I do that in the ladder logic.
thank you
best regards

Mylo · Nov 28, 2003

You can of course do this in ladder logic. for a pre-defined small sequence perhaps you wish to use a function/fuction block for a particular event to occur. either way your "Logic" will dictate what occurs when the button is pressed via sets/resets/outputs/bit logic.

Define your process,
have a crack at it yourself,
post your problems here !!!!!!!

mhmtfthnl · Nov 29, 2003

I have written a simple sample program and sent it that is attached for you.How can I execute this program again and again when I push to I0.0

Thanks for help
Best regards

cnjihia · Nov 29, 2003

I believe you have your program in a function then in that case just go to OB1 and call the function from there as follows.
call FC1 //this is for a function called FC1
The program would be as follows
A IB 0 // this would only be for the first input byte
// do whatever you want in the program for example output it to byte 0
=QB 4.0

RRobbins · Nov 29, 2003

Put this in OB1

NETWORK 1

A I 0.0 // Here is your START button
AN M 0.0 // If you want to make a 1 shot, ADD this
JC FC 1 // Your Program

NETWORK 2

A I 0.0 // If you use the 1 shot, ADD this
= M 0.0 // If you use the 1 shot, ADD this

The Dark Knight · Nov 29, 2003

why not use a one shot instruction???

A I 0.0
FP M 0.0
JC FC 1

This way, you only need 1 rung

mhmtfthnl · Nov 30, 2003

Hi. I have tried both of ways that you suggested me.But I could not manage it.Therefore I am sending my sample program in attached file.
In addition ,is specified fc1 function or label.If it is a label,where should I define it.

RRobbins · Nov 30, 2003

I have attached OB1 and how to jump to FC1

Peter Nachtwey · Nov 30, 2003

I think there has been a misunderstanding.

What I think is wanted is a means of keeping track of state. This means latching the input and clearing the previous latched input.

Code:

      A I0.0      // Check input for program 1
      S M0.0      // Set the State bit
      R M0.1      // Clear the previous states.
      R M0.2
      R M0.3

      A I0.1      // Check input for program 2
      R M0.0
      S M0.1
      R M0.2
      R M0.3

      A I0.2      // Check input for program 3
      R M0.0
      R M0.1
      S M0.2
      R M0.3

      A IO.3      // Check input for program 4
      R M0.0
      R M0.1
      R M0.2
      S M0.3

// Program one

PRG1: A M0.0         // PROGRAM ONE
      JNC END1
                     // PROGRAM ONE GOES HERE
END1:

PRG2: A M0.1         // PROGRAM TWO
      JNC END2


END2:

PRG3: A M0.2         // PROGRAM THREE
      JNC3

END3:

PRG4: A M0.3         // PROGAM FOUR
      JNC END4
      
END4:

      END

This is a brute force way of doing this.

I would use the inputs to set a byte value called State. State can only hold value from 0 to 255 and should not be allowed to change unless a new buttons is pressed. I would then use the JL instruction to jump directly to the correct part of the program rather than scan the whole program to see if it is run.

Code:

        A   I0.0
        JNC E0
        L   0
        T   State
E0:

        A   I0.1
        JNC E1
        L   1
        T   State
E1:

        A   I0.2
        JNC E2
        L   2
        T   State
E2:

        A   I0.3
        JNC E3
        L   3
        T   State
E3:

        L   State         // LOAD THHE PROGRAM NUMBER
        JL  LAST          // JUMP DISTRIBUTOR
        JU  PRG1          // LIST OF DESTINATIONS
        JU  PRG2
        JU  PRG3
        JU  PRG4
LAST:   JU  END4

PRG1:                    // PROGRAM ONE
        JU  END4         // JUMP PAST THE PROGRAMS

PRG2:                    // PROGRAM TWO
        JU  END4         // JUMP PAST THE PROGRAMS

PRG3:                    // PROGRAM THREE
        JU  END4         // JUMP PAST THE PROGRAMS

PRG4:                    // PROGAM FOUR


END4:

See the example in the STL on-line help.

To get a set of inputs converted to a number that the JL instruction could use I woud use my ENC FC described in a previous thread.

sanwilliam · Oct 30, 2010

how to use in scl language timer & counter

Cyclic program operation in s7-300

mhmtfthnl

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Mylo

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mhmtfthnl

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cnjihia

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RRobbins

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The Dark Knight

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mhmtfthnl

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RRobbins

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Peter Nachtwey

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sanwilliam

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