Program instructions 
  7.3 Communication 
S7-200 SMART 
System Manual, V2.3, 07/2017, A5E03822230-AF 
195 
The following figure shows an example to illustrate the utility of the GET and PUT 
instructions. For this example, consider a production line where tubs of butter are being filled 
and sent to one of four boxing machines (case packers). The case packer packs eight tubs 
of butter into a single cardboard box. A diverter machine controls the flow of butter tubs to 
each of the case packers. Four CPUs control the case packers, and a CPU with a TD 400 
operator interface controls the diverter.  
 
Out of butter tubs to pack; t=1, out of butter tubs 
Box supply is low; b=1, must add boxes in the next 30 minutes 
Glue supply is low; g=1, must add glue in the next 30 minutes 
Error code identifying the type of fault experienced 
Fault indicator; f=1, the case packer has detected an error