AWL crazy loop

[marcosouplex]

Hello all,

I'm coming to you for a small coding issue...
I'm working on S7 5.5 (coding a S7 300) for self training (I'm a newbies).

I explain the problem : I use the siemens routine as base time :

UN T 1
L S5T#500MS
SV T 1
NOT
BEB
L DB1.DBB 2
INC 1
T DB1.DBB 2

It generate a binary number in DB1.DBB2 (global variable).
My time set point is a byte variable in hex stored in DB1.DBB4 (global variable).
I want to generate a blinking bit that acts when this set point (for example 8 (hex) is reached).
It means 8 x 500 MS, for instance 4 secs.
The set point is a byte variable that I increase or decrease by action on push buttons. There are a max and min limit that are also adjustable.

I already tried to mask the value with xow or uw, but it seems to simple for this problem.
I tried also with mathematics funtions, but can't achieve good results...

Have anyone some ideas to solve this problem ????

Да свиданя

[marcosouplex]

Hello,

I found the solution ))))
I tryed it on plcsim and it's working right....
I first determine the most significant bit in the set point. (in ex bit n°3)
Then I reverse the upper bits (in ex 1111_1000)
Then I inverse those bits (in ex 0000_0111)
Then I And Word with current clock number (in ex 0000_0111 & 0010_0010 when clock is on 34(decimal) -> result 0000_0010)
could be 0000_0111 & 0010_0011 when clock is on 35(decimal) -> result 0000_0011
Then I And Word with set point (in ex 0000_0010 & 0000_0010)
And finally I stat my blinking bit if this result is on 1.

Hereafter the tricky code

I think it's possible to optimize this code. (a bit)
I'll make it later....

code

Show

Code: Select all

     // Determine the most significant bit in set point

         L     DB1.DBB    4                //Load time set point
         T     DB1.DBB   12               //put it in temporarly value
         L     W#16#1                     //Load minimum value (1)
         <=I   
         SPB   FINO                         //If minimum value reached
         L     W#16#0                      //load 0
         T     DB1.DBB   13                //Put it in MSB counter (most significant bit)

RETO: L     DB1.DBB   12                 //Load the time set point (temp val)
         RRD   1                               //rotate right double 1 bit
         T     DB1.DBB   12                //Put in temp val
         L     DB1.DBB   13                //Load MSB counter
         INC   1                               //add 1
         T     DB1.DBB   13                //save new value
         L     DB1.DBB   12                //Load time set point (temp val)
         L     W#16#1                      //Load 1
         >I                                     //>????
         SPB   RETO                         //if yes, loop whenever > 1
         SPA   FINI                          //Otherwise end loop

FINO: L     W#16#0                      //Load 0
        T     DB1.DBB   13                //The 0 bit is MSB

FINI: NOP   0

//Setting up the bit mask

         L     B#16#FF                      //Load just 1 in the accu
         T     DB1.DBB   12                //Put them in the temp val (which is a bit mask now)
BOUL: SLW   1                             //shift left word 1
         T     DB1.DBB   12                //store in temp value
         L     DB1.DBB   13                //MSB bit number
         L     B#16#0                      //Load zero
         ==I                                  //if zero
         SPB   ZERO                        //goto zero
         L     DB1.DBB   13                //load the MSB bit number
         DEC   1                              //decrement 1
         T     DB1.DBB   13                //store in bit number
         L     DB1.DBB   12                //Load bit mask
         SPA   BOUL                         //loop to bool -> until bit mask is > 0

ZERO: L     DB1.DBB   12                //Load the mask (it has now 111 on the bits upper MSB)
         INVI                                  //inverse word
         L     W#16#FF                    //load only 111 on a byte
         UW    
         T     DB1.DBB   12                //The MSB and upper are now 0 and the rest is 1
         L     DB1.DBB    2                 //Load the current time
         UW                                    //logical and
         L     DB1.DBB    4                  //Load time set point
         ==I                                   //result of UW is equal to time set point
         SPBN  FINU                         //not equal finish
         S     DB1.DBX    9.0              //otherwise set blink bit
         FP    DB1.DBX    9.1              //store flank positive
         =     DB1.DBX    9.2              //9.2 at one on one OB1 cycle

FINU: R     DB1.DBX    9.0              //reset du bit blink

[pravda_ha]

Hello,
If not the time, the time started.
If the time is on, the word counter count.
So the timer works independent.
BEB= Block end conditional; that means if the status bit=1, no counting in the db-word.

BR from Polkovice.
ha