Description:
In a SIMATIC S7-400 station, the CP443-1EX20 with firmware V1.0 is operated on a CPU V5.1, for example CPU 414-3PN/DP. The CP443-1EX20 version V1.0 and the CPU version V5.1 are configured in the STEP 7 Hardware Configuration. The CP443-1 EX20 is operated as PROFINET IO controller.

After configuration of the S7-400 Station and the PROFINET IO system, the configuration is loaded into the CPU of the S7-400 station. It is now possible to exchange data between the CP443-1EX20 as PROFINET IO controller and the PROFINET IO devices connected. You can stop and start the components. The whole configuration can be loaded multiple times.

If the CP443-1EX20 V1.0 is defective, you can use the CP443-1EX20 V2.0 as spare part without changing the configuration in STEP 7.

Special feature
Startup problems might occur in the constellation described. This occurs sporadically when the configuration is loaded.
The configuration is reloaded if the CP is already in RUN mode. In this case, the load process might be aborted. The CP can no longer be reached via the LAN.

In the CPU's diagnostics buffer you are informed of the event by the following entries. The "no connection" fault type and the specified slot indicate the CP.

Excerpt from the CPU's diagnostics buffer
Event 14 of 133: Event ID 16#6547
Parameter error when parameterizing modules (not via P bus, but abort of download)
not user-relevant: SDB number : 3000
Type of fault: no connection or disconnection
Module affected in subrack 0 and slot 10
Mode: STOP (internal)
internal error, incoming event

Remedy
There are the following possible remedies for the case described.

• Upgrade the CPU's firmware to version V5.2 or higher.
• Switch off the power supply. Switch on the power supply again and you can reload the configuration. After successful completion of the download, the S7-400 station starts to operate again. Note that the startup problem might reoccur with future download processes.

Note:
Entry ID 24890935 contains among other things information on the compatibility between S7-400 CPU and CP443-1EX20.