Siemens SIMATIC S7-200 System Manual page 61

The S7-200 Provides a User-Controlled LED
The S7-200 provides an LED (SF/DIAG) that can indicate red (system fault LED) or yellow
(diagnostic LED). The diagnostic LED can be illuminated under user program control, or can
automatically illuminate under certain conditions: when an I/O point or data value is forced, or
when a module has an I/O error.
To configure the automatic selections for
the diagnostic LED:
1. Select the View > Component >
System Block menu command
and select Configure LED.
2. Click each item to either enable or
disable turning on the LED when
an I/O point or data value is forced,
or when a module has an I/O error.
3. Download the modified system
block to the S7-200.
To control the state of the diagnostic LED
with your user program, use the with your user program, use the
Diagnostic LED instruction in Chapter 6.
The S7-200 Maintains a History Log of Major CPU Events
The S7-200 maintains a log that contains
a time-stamped history of major CPU
events, such as when power is applied,
when the CPU enters RUN mode, and
when fatal errors occur. Your time-of-day
clock must be configured in order to get
valid time and date stamps on the log
entries.
To view the Event History log, select the
PLC > Information menu command and PLC > Information menu command and
select Event History.
The S7-200 Allows You to Increase Your Available User Program
Memory
The S7-200 allows you to disable the run
mode edit feature in the CPU 224,
CPU 224XP, and CPU 226 in order to
increase the amount of program memory
available for your use. Refer to Table 1-1
to see the amount of program memory
for each CPU model.
To disable the run mode edit feature,
follow these steps
1. Select the View > System Block
menu command and select
Increase Program Memory.
2. Click the Increase Memory item to
disable the run mode edit feature.
3 3. Download the modified system D l d th
block to the S7-200.
Figure 4-29 Diagnostic LED
Figure 4-30 Viewing the Event History Log
difi d t
Figure 4-31 Disable Run Mode Edit
PLC Concepts Chapter 4
47