Designing The Control Logic For Turning On The Alarm And Modem Dialer - Siemens Simatic S7-200 CPU 210 System Manual

Getting Started with a Sample Program

Designing the Control Logic for Turning On the Alarm and Modem Dialer

Because the outputs turn on immediately, the program uses memory bits (M) for storing the
results of the control logic. See Figure 3-9. At the end of the program, these bits turn on (or
off) the outputs.
Network If the LED bit is on, turn on the output for the system
LED.
LED_Bit
Network If the Alarm bit is on, turn on the output for the alarm.
Alarm_Bit
Network If the low-level alert bit is on, turn on the output for the
low level alert.
Low_Bit
Figure 3-9 Control Logic for Turning On the Outputs
As shown in Figure 3-10, the memory bits for the alarm siren and the modem dialer are
turned on by either of two conditions:
Someone pushes the "panic button" (regardless of the arm/disarm state of the system
and without providing the low-level alert notification).
The system has not been disarmed during the 60 seconds that the low-level alert
notification has been on.
Turning on the alarm also resets the low-level alert notification.
Network
Panic_Alarm
Alert_Timer
>=I
+600
Figure 3-10 Control Logic for Enabling the Alarm and Modem Bits
3-8
LAD
LED
Alarm
Low_Alert
LAD
Alarm_Bit
S
1
Armed Modem
S
1
Low_Bit
R
1
STL
NETWORK
LD M0.0
= Q0.0
NETWORK
LD M0.1
= Q0.1
NETWORK
LD M0.2
= Q0.2
STL
NETWORK
LD I0.3
LDW>= T0, +600
A I0.2
OLD
S M0.1, 1
S Q0.3, 1
R M0.2, 1
S7-200 Programmable Controller, CPU 210
C79000-G7076-C235-01