Description
Original instructions
About us
Description of the function
The PL7_MONOSTABLE function block is a monostable that allows a pulse to be generated with a precise duration.
The additional parameters EN and ENO can be configured.
NOTE: you cannot instantiate or modify the PL7_MONOSTABLE function in online mode. This means you must be in offline mode and therefore you must transfer the project in the PLC.
NOTE: If you create more than 255 instances of PL7_MONOSTABLE the application cannot be transfered in the PLC.
FBD representation
Representation:
LD representation
Representation:
IL representation
Representation: 
CAL Mn_1(S := Mn_Start, R => Mn_State)
ST representation
Representation: 
IF RE(Mn_Start) THEN
   START_PL7_MONOSTABLE (Mn_1) ;
END_IF ;


Mn_State := Mn_1.R ;


          


          


Description of parameters          


The following table describes the input parameters:          



















Parameter          






Type          






Comment          












S               






BOOL               






"Start" input, on rising edge, starts the monostable.               





               


The following table describes the output parameters:               



















Parameter               






Type               






Comment               












R               






BOOL               






"Run" output:               



    

  • 


    Mn_1.R  = 0 if Mn_1.ET = Mn_1.PT or Mn_1.ET = 0.               
    • 

  • 


    Mn_1.R  = 1 otherwise.               
    • 







               


NOTE:  the monostable can be reset on the rising edge of Ma_1.S, on the other hand, the length of the monostable starting pulse does not change the pulse generated as the monostable is started on the rising edge.               


               


               


Description of variables               


The following table describes the public variables:               



















Parameter               






Type               






Comment               












ET               






INT               






Current value of the monostable which runs down over time from Mn_1.PT to 0. This value can be read and tested but not written by the program.               











PT               






INT               






This value, which is between 0 and 9999, is known as the monostable preset value. It can be written, read and tested by the program. Its default setting is 9999. The value of the pulse generated by the monostable is equal to Mn_PT x TB.               











TB               






UINT               






Cyclical programmer time base. Possible values:               



    

  • 


    TB = 8: 1 mn (default value),               
    • 

  • 


    TB = 4: 1 s,               
    • 

  • 


    TB = 2: 100 ms,               
    • 

  • 


    TB = 1: 10 ms.               
    • 





When the program is executed, the value of the time base (TB defined in offline mode) is rounded down to the nearest multiple of 2 (between 1 and 8).               





               








 CAUTION    







UNEXPECTED BEHAVIOR AFTER WARM RESTART    


Do no modify the time base (TB) in online mode, this would cause an unexpected behavior of the application on warm restart.    


Failure to follow these instructions can result in injury or equipment damage.