Start-Up And Program Tests - Siemens SIMATIC S5-100U System Manual

S5-100U
4

Start-up and Program Tests

4.1 Operating Instructions
4.1.1 CPU Operator Panel
Battery low
(yellow LED lights:
battery discharged or
not installed)
ON/OFF switch
ON/OFF Switch
The ON/OFF switch turns on the CPU's voltage regulators. This switch does NOT separate the
voltage regulator from the L+/M terminals.
Operating Mode Switch
Use the operating mode switch to select either the RUN or STOP operating mode. The CPU
automatically goes into the START-UP mode during the transition from STOP to RUN (see section
7.4.2).
4.1.2 Operating Modes
STOP Operating Mode
• The program is not executed.
• The current values for timers, counters, flags, and process image I/O tables are saved when the
STOP mode begins.
• The output modules are disabled (signal status "0").
• The process image I/O tables, timers, and non-retentive flags and counters are set to "zero"
during the transition from STOP to RUN.
RUN Operating Mode
• The program is processed cyclically.
• Already started timers continue to run.
• The signal states for the input modules are stored.
• The output modules are addressed.
• The RUN operating mode can also be set after an OVERALL RESET, that is, when the program
memory is empty.
EWA 4NEB 812 6120-02b
BATTERY
OFF/
LOW
STOP
RUN
I
STOP
O
COPY
Figure 4.1 CPU Operator Panel
Start-up and Program Tests
Operating mode display
RUN
(green LED: RUN)
Operating mode display
(red LED: STOP)
Operating mode switch
4-1