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3.
Notes on program development
Power up
When t h e power supply i s switched on
o r on recovery of t h e power supply a f t e r
a power f a i l u r e , t h e P C assumes t h e
f o l l o w i n g s t a t e s w i t h o u t having t o
t a k e any a d d i t i o n a l measures i n t h e
user program:
F i g . 5: Automatic mode s e t t i n g
f o l l o w i n g power-up
Prevention o f automatic r e s t a r t i n
general
Flag* F 63.7 can be used t o prevent
automatic r e s t a r t on power-up.
This f l a g i s s e t by t h e operating
system o f t h e P C on power-up i f
t h e "RUN" mode i s s e t
and
was s e t
p r i o r t o power-down. I n order t o
enable manual r e s t a r t , f l a g F 63.7
i s r e s e t i n t h e "STOP" mode. It can
a l s o be r e s e t by t h e user program (e.g.
i n c o n j u n c t i o n w i t h an i n p u t s i g n a l ) .
E r r o r
i dent i
-
f i e r * s e t
-
YE S
- - - - - - - - t
I
NO
Operating mode
o f PC p r i o r t o
power-up
STOP
RUN
POWER OFF
l
P O W E R O N
*
I n t e r n a l r e 1 ay e q u i v a l e n t
Operating
mode f o l l o w -
i ng power-up
-
STOP
STOP
S TOP
-
RUN
Current p o s i t i o n
o f mode selec-
t o r o f t h e P C on
power-up
-
STOP
L
RUN
Programning example
) +
F63.7;
"1"
I
I
User-
!
I
I---
F 63 7
&
"9"
l
I
*
A f a u l t has occurred i n program scanning
and t h e reason f o r t h i s i s stored
i n t h e i n t e r r u p t stack.
P r e v e n t i n q automatic r e s t a r t on b a t t e r y
f a i l
ure
Flag F 63.6 can be used t o prevent auto-
m a t i c r e s t a r t on b a t t e r y f a i l u r e ( r e t e n -
t i v e f l a g s r e s e t ) .
F l a g F 63.6 i s s e t by t h e o p e r a t i n g
system o f t h e P C on power-up i f t h e
backup b a t t e r y f a i l s o r i s n o t connec-
ted. The P C must be s e t t o t h e "RUN"
mode i n t h i s case.
F l a g F 63.6 i s r e s e t by t h e "ERASE
PROGRAM" f u n c t i o n o r by t h e user p r o -
gram (e.g.
i n c o n j u n c t i o n w i t h an i n p u t
s i g n a l ) .
Programming example
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