Profibus Configuration - Softing NETLink S7-Compact User Manual

The network settings can be adapted manually if the checkmark next to Automatic Baud Rate
Detection is removed. This is usually only necessary if the NETLink S7-Compact fails to sign onto the
bus system automatically (can happen with passive bus participant).
Some older Siemens CPUs do not support the auto baud function on the MPI. PPI systems do not
usually support this function either. In such cases, the network-related parameters should be
adapted manually.
The transmission speed and the HSA of the PLC being addressed must be known and identical to all
connected bus nodes.
It is also possible that the auto baud function may not function reliably at transmission rates slower
than or equal to 19.2 Kbps or with increased use of communication via global data exchange, because
the relevant frame is transmitted more irregularly by the CPUs. In such cases it may be advantageous
to assign the bus parameters manually.
5.1.2.2

PROFIBUS configuration

Basically, the same applies to PROFIBUS configuration as to MPI configuration. However, the
network-related parameters are more extensive.
In addition to the parameters transmission rate and highest station address mentioned in Section
20
MPI , PROFIBUS also has parameter field for selecting the bus profile and bus parameters.
If the NETLink S7-Compact Gateway is the only active station on the PROFIBUS, it operates in so-
called single-master mode, i.e. it generates the token cycle with the set bus parameters.
If the bus speed on the PROFIBUS is set to a value less than 187.5 Kbps, please remember that it may
take up to half a minute for the bus parameters to be recognized.
Version EN-062023-1.00
Note
Enabling the Automatic transmission rate detection option will make connections take a
little longer to initialize, since it will make it necessary to find out what the
corresponding online parameters are. This function may not work reliably with slow bit
rates (e.g., 19.2 kbps) and global data communications.
Chapter 5 - Configuration
21