Siemens Simatic S7-200 CPU 210, System Manual

Page: 58 / 140

3-18
S7-200 Programmable Controller, CPU 210
C79000-G7076-C235-01
Refer to Figure 3-18 and follow these steps to enter the two contacts on the second rung of
the first network:
1. Select “Contacts” from the family listing and select “>= Integer” from the instruction listing.
This inserts a comparison instruction at the cursor position. This instruction compares the
value of the notification timer (Alert_Timer) with the time value.
2. Type either the symbolic name
Alert_Timer
or the absolute address
T0
in the
highlighted area. Pressing ENTER highlights the second value for the comparison.
3. Type
600
and press ENTER. This instruction becomes true (and turns on) when the timer
is greater than or equal to 600, which equals 60 seconds.
4. Click the F4 toolbar button to create a normally open contact. Type
Armed
(or
I0.2
) and
press ENTER.
Contacts >= Integer
Network 1
F4 F5 F8 F7 F6 F10
F3 F2
Sound the alarm!
“Panic_Alarm”
== Integer
Normally Open
Normally Closed
Not
<= Integer
Positive Transition
Negative Transition
>= Integer
Select “>= Integer” from the
instruction listing.
Contacts >= Integer
Network 1
F4 F5 F8 F7 F6 F10
F3 F2
Sound the alarm!
“Panic_Alarm”
S
1
“Alarm_Bit”
VW0
>=I
VW0
Contacts Normally Open
Network 1
F4 F5 F8 F7 F6 F10
F3 F2
Sound the alarm!
“Panic_Alarm”
S
1
“Alarm_Bit”
>=I
+600
“Alert_Timer”
“Armed”
Enter the address:
T0
or
Alert_Timer
Press ENTER and then
enter the time value:
600
Insert a normally open
contact and enter
I0.2
( or
Armed
).
Select “Contacts” from
the family listing.
Figure 3-18 Entering the Comparison Instruction and Next Contact
Getting Started with a Sample Program