Operating the Controller - CPU 41x-2 PCI
Windows Automation Center, WinAC Slot Version 4.0
64
Hardware Installation and Operating Manual, Edition 02/2006, A5E00273194-02
4.4
Resetting the Memory Area : MRES Command
(CPU Menu)
MRES performs a memory reset of the controller by resetting the controller to its
initial (default) state. A memory reset deletes the STEP 7 user program and the
system data (configuration) and also disconnects any online communications, for
example, STEP 7, WinCC, WinCC flexible, PROFIBUS, or S7 communications.
You typically perform an MRES before downloading a new program to the
controller. You
must
perform a memory reset if the STOP indicator on the
controller panel is flashing slowly. This can occur when:
•
CPU 41x-2 PCI has been inserted or moved in the Station Configuration Editor.
•
Memory card has been removed and inserted.
Use one of the following methods to reset the memory:
•
Click the MRES button on the control panel
•
Select the
CPU > MRES
menu command
•
Press the ALT+C+M keys
You can also use STEP 7 to perform a memory reset.
MRES switches the controller to STOP mode, if necessary, and then performs the
following tasks:
•
Deletes the entire STEP 7 user program (OBs, DBs, FCs, FBs, and the system
data) from both the work memory area and the load memory area
•
The content of the memory areas (I, Q, M, T, and C) is reset to 0 (except for
time of day).
•
System settings are reset to their default values (e.g., size of process image
areas and size of diagnostic buffer).
•
Deletes all active communications jobs (for example, TIS) and all open
communications
•
If a FLASH card is not inserted, the reset controller has a memory utilization of
"0". The utilization can be read out with STEP 7.
If a FLASH card is inserted, the controller copies the user program and the
system parameters stored on the FLASH card onto the work memory area
when the memory reset is complete.
After MRES, the 120 most recent diagnostic buffer entries are retained.
The STOP indicator flashes while the memory reset is in progress. After the
memory has been reset, the diagnostics buffer is resized to its default size. Input (I)
and output (Q) memory areas are also reset to their default sizes. After a memory
reset, you must reconfigure these values to your own specifications.
