EXplain the program PLC FC50, FC51

[Mohammadali Gerami]

Hi All
In my plc program in following picture there are functions FC50 in the begining and FC51 in end of organization block OB32.
I can not understand the purpose of two functions (FC50, FC51) in OB32.
Any help much appreciated please.
Thanks a lot.

 

[L D[AR2P#0.0]]

Is that the totality of the code in FC50 and FC51?

 

[drbitboy]

I can not understand the purpose of two functions (FC50, FC51) in OB32.

Do you have any guesses what they are doing?

Do you see the symmetry between them?

Do you think it is significant that FC50 is called at the beginning of the other program, and FC51 is called at the end?

http://www.plcdev.com/statement_list_stl_cheat_sheets

 

[L D[AR2P#0.0]]

Post the interfaces of the FC's. What model CPU is it - any idea how long it's been in use?