Preliminary remarks:
Interface problems in Multimaster mode often occur if you are not using one of the two following RS232/PPI cables which you should be using with STEP 7 Micro/WIN as from V3.2 SP4.
| Product |
MLFB |
| Intelligent RS232/PPI cable with built-in RS232/RS485 converter |
6ES7 901-3CB30-0XA0 |
| Intelligent USB/PPI cable with built-in USB/RS485 converter |
6ES7 901-3DB30-0XA0 |
If you use the above cables, it provides Multimaster functionality.
Instructions:
Problems in Multimaster mode when using an RS232/PPI cable that are attributable to too long a response time by the COM interface on the PC side can be cleared as follows:
| Step |
Procedure |
| 1 |
Right-click on the "Workstation" icon and then select "Properties". |
| 2 |
Go to the "Hardware" tab and open "Device Manager". |
| 3 |
Double-click on "Connections (COM and LPT)" to open the subtab containing the different connections of the PC. |
| 4 |
Double-click on the port used for PPI communications. |
| 5 |
In the "Connection Settings" tab select the "Advanced" button. |
| 6 |
In the dialog box "Advanced settings for COM(X)" you select the lowest values for receive and transfer buffer and then acknowledge with "OK". |
| 7 |
You must restart the computer to activate the new settings. |
Note:
When using Windows NT with a PC/PPI cable, no other masters should be present on the network. So you cannot make the settings described above in Windows NT. In this case you should choose an MPI/PROFIBUS card (see Entry ID: 22634774).
| 
german
