Go to program line 24 und up.
You can see discretes inputs I01...I10 triggers alarm marker
M81.....M90.
M81 to M90 are the contents of word 06 which is ANDed with shift register contents word 07 by BV32.
For an explaination of M,MB,MW,MD memory area go to EASY-SOFT online help,choice marker and you will find a table.
Go with EASY-Soft in simulation mode and set one or more of Inputs I01...I10 to ON condition and the correponding mask(1...10)should be shown for 5 sec.
A good way for understanding programs is to increasing cycle time,for example to 1sec.
Then users have enough time to observe program flow.
Regards,
Julian