reset plc

sir i want to siemens s7 300 plc cpu reset. How to reset this

Using the reset menu in the software or (if possible - depends on the CPU type) by putting the switch/key in the MRES position in the right way. The procedure is written down in the manual.

Visit the following site for manual, .
http://manuali.eltex.biz/Manuali_Siemens/S73bhb_e.pdf

Page 131gives following description, page 132 gives graphical version of reset
(I could not copy page 132, it gives graphical description of reset.)

8.4 Resetting the CPU Memory
You must reset the CPU memory
_ before you transfer a new (complete) user program to the CPU
_ if the CPU requests a MRES with its STOP LED flashing at 1-second intervals.
Possible reasons for this request are listed in Table 8-3.

Table 8-3 Possible Reasons for MRES Request by CPU
Reasons for MRES Request by CPU Remarks
Wrong memory card has been plugged in. not with CPU 312 IFM/314 IFM
RAM error in CPU –
Working memory too small, that is CPU with 5V FEPROM memory card plugged in:
not all blocks of the user program on When one of these reasons applies, the CPU requests
a memory card could be loaded. memory reset once. After that, the CPU ignores the contents of the memory card enters the error reasons in the diagnostics
Attempt to load blocks with errors, buffer and goes to STOP. You can erase the contents of the
for example if a wrong command 5V-FEPROM memory card in the CPU or enter new program.
has been programmed.

Resetting the CPU Memory Using the Mode Selector
To reset the CPU memory using the mode selector, do the following (also see Fig. 8-7):
1. Turn the key to the STOP position.
2. Turn the key to the MRES position. Hold the key in this position until the STOP LED lights up for the second time (this takes 3 seconds).
The CPU acknowledges the reset request.
3. Within 3 seconds, you must turn the key back to the MRES position and hold it in this position until the STOP-LED flashes (at 2 Hz).
When the CPU has completed the reset, the STOP LED stops flashing and remains lit.
The CPU has performed the reset.
Regards.

S7 300 Memory Reset

Page 132 of the manual gives graphical version of reset


[FONT=&quot]Resetting the CPU Memory Using the Mode Selector[/FONT]
[FONT=&quot]To reset the CPU memory using the mode selector , do the following (also see Fig. 8-7):[/FONT]
[FONT=&quot]1. Turn the key to the STOP position.[/FONT]
[FONT=&quot]2. Turn the key to the MRES position. Hold the key in this position until the STOP LED lights up for the second time (this takes 3 seconds).[/FONT]
[FONT=&quot]The CPU acknowledges the reset request.[/FONT]
[FONT=&quot]3. Within 3 seconds, you must turn the key back to the MRES position and hold it in this position until the STOP-LED flashes (at 2 Hz). [/FONT]
[FONT=&quot]When the CPU has completed the reset, the STOP LED stops flashing and remains lit.[/FONT]
[FONT=&quot]The CPU has performed the reset.[/FONT]

S7 300 Memory Reset

Visit the following site for manual, .
http://manuali.eltex.biz/Manuali_Siemens/S73bhb_e.pdf

Page 132 of the manual gives graphical version of reset


[FONT=&quot]Resetting the CPU Memory Using the Mode Selector[/FONT]

[FONT=&quot]To reset the CPU memory using the mode selector , do the following (also see Fig. 8-7):[/FONT]
[FONT=&quot]1. Turn the key to the STOP position.[/FONT]
[FONT=&quot]2. Turn the key to the MRES position. Hold the key in this position until the STOP LED lights up for the second time (this takes 3 seconds).[/FONT]
[FONT=&quot]The CPU acknowledges the reset request.[/FONT]
[FONT=&quot]3. Within 3 seconds, you must turn the key back to the MRES position and hold it in this position until the STOP-LED flashes (at 2 Hz). [/FONT]
[FONT=&quot]When the CPU has completed the reset, the STOP LED stops flashing and remains lit.[/FONT]
[FONT=&quot]The CPU has performed the reset.[/FONT]