
STEP 5 Programming IP 266
Every "Command FB" includes the following code-evaluation routine:
Input set
AND auxiliary flag
not set?
Edge flag = 1Edge flag = 0
Input set?
Auxiliary flag = 1Auxiliary flag = 0
Setting auxiliary flags and edge flags
Edge flags
A I 3.1
AN F 4.0
= F 4.1
Auxiliary flags
A I 3.1
= F 4.0
yes
no
yes
no
This routine works with auxiliary flags and edge flags, and ensures that a
command is entered in the output byte only once in the first cycle that follows
setting of the input. Edge flag 4.1 is used for this purpose.
0th cycle Switch/key is actuated
1st cycle Input appears in the PII as being set
Auxiliary flag = 1
Edge flag = 1
2nd to nth cycle Input remains set
Auxiliary flag = 1
Edge flag = 0
Frame
is entered in output byte
is not entered in output byte
9-26
EWA 4NEB 812 6057-02
Comentarios a estos manuales