Botu PLC Sequential switch function block (SCL)

The program of this blog post is very simple , Just provide a programming idea and reference code for beginners , We will take the sequential switching of air conditioning units as an example to explain . Many equipment in the industrial field require that the startup and shutdown must follow certain timing restrictions , When the device is started, some devices need to be turned on first , Some equipment needs to be turned on later . When shutting down, some devices need to be turned off first, and some devices need to be turned off later . For this demand of switching on and off , We can design a sequential switch FB. Limited to my level and ability , Mistakes and deficiencies are inevitable in the text , Welcome criticism . At the same time, thank you for your attention and subscription .

1、 Turn on and off the machine in sequence FB

2、 complete SCL Code

FUNCTION_BLOCK "SequenceControl"
{ S7_Optimized_Access := 'TRUE' }
VERSION : 0.1
   VAR_INPUT 
      bStart : Bool;   //  Start up in sequence 
      bStop : Bool;   //  Reverse shutdown 
      bEstop : Bool;   //  Emergency stop 
      diDf_ontime : DInt := 1;
      diDf_offtime : DInt := 1;
      diLqp_ontime : DInt := 1;
      diLqp_offtime : DInt := 1;
      diLdp_ontime : DInt := 1;
      diLdp_offtime : DInt := 1;
      diLj_ontime : DInt := 1;
      diLj_offtime : DInt := 1;
   END_VAR

   VAR_OUTPUT 
      bDf : Bool;   //  Butterfly valve