System and operating states of the CPU 410
7.4 Performing a memory reset
CPU 410 Process Automation/CPU 410 SMART
System Manual, 05/2017, A5E31622160-AC
117
For detailed information on SFC 90 "H_CTRL", refer to Manual
System Software for S7-
300/400, System and Standard Functions
.
-safe system, you are not allowed to disable and then re-enable the cyclic self-tests.
Performing a memory reset
Memory reset process in the CPU
You can perform a memory reset of the CPU from the ES. During a memory reset, the
following process occurs on the CPU:
● The CPU deletes the entire user program in the main memory.
● The CPU deletes the user program from the load memory.
● The CPU deletes all counters, bit memories, and timers, but not the time of day.
● The CPU tests its hardware.
● The CPU sets its parameters to default settings.
The LEDs behave as following during the memory reset:
1. The STOP LED flashes for about 1-2 seconds at 2 Hz.
2. All LEDs light up for approximately 10 seconds.
3. The STOP LED flashes for approximately 30 seconds at 2 Hz.
4. The RUN LED and the STOP LED flash for approximately 2 seconds at 0.5 Hz.
This operation can also take a few seconds longer depending on the utilization level of
the memory.
5. The RUN LED and the STOP LED flash for approximately 2 seconds at 0.5 Hz.
If a large data volume is being deleted, the LEDs may flash longer.
6. The STOP LED lights up permanently.
Data retained after a memory reset...
The following values are retained after a memory reset:
● The content of the diagnostic buffer
● The baud rate of the DP interface
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