If you want to connect a WinCC flexible operator panel to an S7-200, make sure that the S7-200 can only be operated as DP slave.
The panel or PC must be implemented as DP master on the PROFIBUS DP network and the S7-200 as DP slave.
The following settings must therefore be made in the WinCC flexible configuration:
- In WinCC flexible you configure a controller connection to the S7-200 via
Project > Communication > Connections.
Fig. 1: Select controller protocol
- To be able to set up communication between the S7-200 as DP slave and the PC as DP master, you must set a check mark to enable "Only master on the bus".
Fig. 2: Only master on the bus
Example:
Five PCs with WinCC flexible Runtime and PROFIBUS DP communicate with an S7-200. One PC is the DP master, i.e. the check mark for "Only master on the bus" is set only for this PC. There is no check mark for "Only master on the bus" set for the other PCs.
Now, if the master PC fails, all communication on the PROFIBUS DP network is interrupted, because there is then no other master available on the bus. As soon as the master PC comes back online (WinCC flexible Runtime is started and the controller connection is enabled), the other PC stations can set up a connection again to the S7-200.
Recommendation:
Declare all the PCs to be master by setting a check mark for "Only master on the bus" for all of them, because then communication does not depend on just one PC.
The other settings for the PROFIBUS DP connection are to be entered accordingly.
Fig. 3: Other settings
Note:
On a PC the PG/PC interface must be set as "S7ONLINE --> PROFIBUS".
Fig. 4: PG/PC interface
STEP 7 - Micro/WIN
With STEP 7-Micro/WIN the interface of the the S7-200 must be configured according to the parameters used in WinCC flexible.
Notes:
- For a PROFIBUS DP communication at a baud rate > 187.5 kbaud you need a DP interface on the S7-200.
- For the S7-22x without integrated DP interface you need an EM277 module for the PROFIBUS DP communication (baud rate > 187.5 kbaud).
- More information on OP communication with S7-200 is available in "S7-200 and HMI Components" in Entry ID: 14188898.
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