show the entry list
S7-1200 CPU 12xx -- Setting up and parameterizing hardware -- Initializing and parameterizing modules
Which settings do you have to make in the TIA Portal to read out messages and status information over the CPU's web server and display them in the web browser?
What is the meaning of the system constants in STEP 7 (TIA Portal) with S7-1200/1500?
How can the CPU analog inputs of the SIMATIC S7-1200 also measure currents of 0-20mA?
How do you program the "GET" and "PUT" instructions in the user program of the SIMATIC S7-1200 CPU in order to transfer more than 160 bytes of data?
Why must you never remove a memory card when the S7-300/S7-400/S7-1200/S7-1500 CPU is in operation (RUN)?
How does startup work in an S7-1200?
What is the connection between subnet masks and IP addresses with regard to subnetting and supernetting (Classless Inter Domain Routing CIDR)?
How can you prevent data loss of runtime-generated parameters when updating your S7-1200 PLC program?
How can you share runtime-generated parameters between several S7-1200 PLCs with a KTP Basic Panel?
How can you change the IP address of an S7-1200 without using STEP 7 Basic?
How can you delete the IP address and reset your S7-1200 to factory settings using the SIMATIC MC memory card (2MB or 24MB)?
How can you download to a network of several S7-1200 PLCs with the same IP address?
How can you reset the IP address of your S7-1200 PLC using STEP 7 Basic software?
How does startup work in an S7-1200?
Part number:

The startup mode "Warm restart - operating mode before POWER OFF" is set by default in the device configuration. This prevents the CPU from changing unintentionally to the RUN mode during the commissioning phase when the power returns. An unintentional change to the RUN mode will set the outputs and start any machines to which the outputs are connected. However, with this default setting you need a PG with STEP 7 V10.5, STEP 7 V11 or the S7-1200 Tool (see Entry ID 41737437) to be able to change the CPU from STOP mode to RUN mode. The CPU can change to STOP mode for one of the following reasons:

  • Inserting an SD card
  • Failure of an expansion module
  • Other reasons

If STOP mode occurs, you need software for changing to RUN mode.

We recommend setting the startup mode "Warm restart – RUN". Then, the CPU changes automatically back into RUN mode when power returns. In this way, neither you nor your customers need customer support’s assistance to set the CPU back into RUN mode.

The table below shows the startup modes of the S7-1200 CPU.
Startup mode CPU behavior
No startup CPU remains in STOP mode.
Warm restart – RUN CPU goes into RUN mode when power returns.
Warm restart - operating mode before POWER OFF CPU goes into the same mode as before loss of power.

As from STEP 7 V11 and firmware version V2.0 you have the option of changing operating modes using the web server if activated.
Proceed as follows.

  1. Open the internet browser and start the web server.
  2. Log on as "admin".
  3. Select the "Start page".
  4. Use the "Go to RUN" and "Go to STOP" buttons to change the operating mode accordingly.

 Entry ID:51825007   Date:2011-12-12 
I regard this helpfulas not helpful                                 
My Documentation Manager 
Support Request
To this entry
Create PDF 
Send to a friend
Compatibility tool 
Online Help
Guided Tour