TIA - Function Call,

[kalabdel]

In your FB6, what happens when #Run is false and the block is called?
Your code is nice and compact so it will not make any real difference in this case but nice to be cognisant of it.

 

[kalabdel]

In your FB6, what happens when #Run is false and the block is called?
Your code is nice and compact so it will not make any real difference in this case but nice to be cognisant of it.

This is not the whole code is it? I recall you saying the block will execute for more than one scan and in that case there will be four conditions, not necessarily ordered this way:


Rising Edge of Run,
Run := TRUE,
Falling Edge of Run,
Run := False;

 

[kalabdel]

So this is basically how I approach two areas that I saw in your code.
IF conditions, I do my best to keep "uniform" (can't think of a better term). For example:


IF COLOR = White THEN
do this stuff;
ELSIF COLOR = BLUE THEN
// here I may prepare condition for another IF or CASE

ENGINE_TROUBLE := TRUE; // blue smoke or something

ELSE
do something different;

END_IF;


What I avoid is mixing two case or if statments:
IF COLOR = WHITE THEN
do this;
ELSIF ENGINE_STATUS = TROUBLE THEN
shut the engine off;
END_IF;


The above is difficult to follow by someone who is not intimately familiar with the code, or me after months or years.


For block enable I pretty much follow a template and add or remove from it as needed but again on requirement is to have my IF condition very easy to follow, a quick scan of the first section tells you when the block is enabled.
Then I follow Siemens and I think PLCOpen recommendation for status and error reporting and that I satisfy the requirement that goes with Enable which is to BLOCK_ENABLED, or ACTIVE or anything you want to call it.

Note: I made some quick changes in the code while posting and hopefully didn't screw it up, should still make the point.

FUNCTION_BLOCK "FB_Enable"

{ S7_Optimized_Access := 'TRUE' }
VERSION : 0.1
VAR_INPUT
  Enable : Bool;
END_VAR

 VAR_OUTPUT
  ob_IS_Enabled : Bool;

   ob_IS_Error : Bool;
  Status : Word;
END_VAR

VAR_IN_OUT

END_VAR

VAR
  Enable_Edge : Bool;
END_VAR

VAR_TEMP
  tmpb_Init : Bool;
  tmpb_IS_Block_Enabled : Bool;
  tmpw_STATUS : Word;
  tmpb_IS_Error : Bool;
 
END_VAR

VAR CONSTANT
  //enable
  BLOCK_ENABLED : Word := 16#7003;   // block enabled
  BLOCK_DISABLED : Word := 16#7004;   // block disabled
  // status
  NO_ERROR : Word := 16#0000;   // No errors
  AWATING_FOR_REQUEST : Word := 16#0001;  // got positions and wating for request to add more or load more
  NO_CURRENT_JOBS : Word := 16#7000;   // Initial value= IDLE
  NO_POS_PENDING : Word := 16#8201; // no positions to process
  INVALID_COUNTER_VALUE : Word := 16#8202;   // counter value is invalid
  INVALID_TARGET_POS : Word := 16#8203; // 1<= target position<=maximum counter value<=2147483647
  INVALID_MAX_COUNTER_VAL : Word := 16#8204; // maximum counter value has to be greater than zero
END_VAR




BEGIN
    // --------------------------------------------------------------------------------------------
    //FUNCTION: Enable
    //---------------------------------------------------------------------------------------------
    //Enables and disables the block
    //-------------------------------------------------------------------------------------------
    IF NOT #Enable AND #Enable_Edge THEN // falling edge of enable
        #tmpb_Init := TRUE; // reset the tags on the way out which is done at the bottom.
    ELSIF NOT #Enable THEN
         // exit block, return**nothing to do**
        #ob_IS_Enabled := FALSE:

         #Status := #BLOCK_DISABLED;
        RETURN;
    ELSIF #Enable AND NOT #Enable_Edge THEN //rising edge of enable
        // intitialize variables
        #tmpb_Init := TRUE;
        
    ELSE
        #ob_IS_Enabled := #tmpb_IS_Block_Enabled := TRUE;
        //block Status
        #tmpw_STATUS := #NO_ERROR; // idle
    END_IF;
    #Enable_Edge := #Enable;
    // --------------------------------------------------------------------------------------------
    //beginning of block execution
    //---------------------------------------------------------------------------------------------
    IF #tmpb_IS_Block_Enabled THEN
         

        // block code goes here
        //
        //
        //





         // Update outputs 
        // ***********output tags here*******
        // output status
        #ob_IS_Error := #tmpb_IS_Error;
        #Status := #tmpw_STATUS;
    END_IF; // end of enable
    
    // --------------------------------------------------------------------------------------------
    //Reset variables
    //---------------------------------------------------------------------------------------------
    IF #tmpb_IS_Block_Enabled THEN
        // Initialize some variables
        ;
    END_IF;
    
    
    
END_FUNCTION_BLOCK

 

[kalabdel]

I forgot to put in your #Finished bit but the way you have it is good. Rising edge of #Finished resets the tag that is connected to #Rum and beyond that the only output from the block is its disabled status.