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Entry type: FAQ, Entry ID: 21490282, Entry date: 01/07/2008

How do you test the I/O using the S7-PLCSIM simulation program?

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The I/O is configured automatically with CPU modules without DP connection (e.g. CPU314). When you plug a module into a controller, that module is automatically identified by the CPU. This configuration cannot be simulated with a simulated automation system. If you load a program from an S7-300 CPU (which configures the I/O automatically) into S7-PLCSIM, the system data does not include an I/O configuration.

In practice, automatically configured S7-300 CPUs (CPUs without DP connection) behave in S7-PLCSIM in the same way as loading program blocks without system data. The CPU does not go into STOP mode either when programming non-existent I/O addresses. The I/O is operated as if any address is available.

All S7-300 CPUs with a DP connection (like the CPU 315-2DP, for example) and all S7-400 CPUs operate the I/O in S7-PLCSIM as it is in reality. There is further information available on this topic in the Online Help for S7-PLCSIM under:

  • "Modifying Your Hardware Configuration". 

The following table explains how to use S7-PLCSIM to test the I/O without any errors. 

No. Description
1 In order to test the I/O without any errors in a project with an S7-300 CPU without a DP connection, you must copy your program blocks into a project with an S7-300 CPU with a DP connection (e.g. CPU 315-2DP). In the SIMATIC Manager, create a new STEP 7 project via "File > New ..." and assign it a project name in the next dialog. Then save with "OK".
2 Now mark the project name in the SIMATIC Manager and then insert an S7-300 station via "Insert > Station > SIMATIC 300 Station".
3 Open the hardware configuration and configure a CPU with a DP connection, e.g. the CPU 315-2DP. The save and compile the hardware configuration.
4 Now copy the blocks (OBs, FBs, FCs and DBs) from your old project into the newly created project with the CPU 315-2DP.
5 After loading the program blocks (including the system data blocks) into S7-PLCSIM, the I/O is operated without any errors.

Note on using S7-PLCSIM for a CPU 317T-2DP (with an MPI/DP interface):
If the CPU 317T-2DP is configured as a DP interface, the S7-PLCSIM simulation program can only be used for the MPI interface. There is further information available on this topic in the Online Help for S7-PLCSIM under:

  • "Modifying Your Hardware Configuration". 

Note on the PG/PC interface:
In S7-PLCSIM V5.4 onwards the connection types DP, Industrial Ethernet and PC Internal are also supported. More information is also available in the readme file of S7-PLCSIM V5.4, under "What's new in S7-PLCSIM V 5.4".


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