Siemens SIMATIC PANEL PC 877 - Manual (Page 52)

Integration into an automation system
7.2 Device in a SIMATIC S7 configuration
SIMATIC Panel PC 877
7-2
Operating instructions, Release 07/2006, A5E00877780-01
7.2
7.2
Device in a SIMATIC S7 configuration
7.2.1 MPI/PROFIBUS-DP network
You can connect the device to a SIMATIC S7 automation system or a PROFIBUS DP
network via the MPI/DP interface. You can connect up to 32 PC, PG, or AS devices to one
network segment. The use of repeaters allows you to interconnect several
MPI/PROFIBUS DP network segments. The complete MPI/PROFIBUS DP network consists
of a maximum of 127 stations.
The device is physically connected to the MPI/PROFIBUS DP network via an electrically
isolated RS485 interface on the PC motherboard. The potential is isolated within the safety
low voltage circuit (SELV).
The transmission rate is limited to 187.5 Kbps with the 5-meter MPI cable for connecting to
the SIMATIC S7-CPU. To achieve baud rates over 1.5 Mbps, you require a 12 Mbps
PROFIBUS cable with the order number 6ES7901-4BD00-0XA0. In the PROFIBUS DP MPI
network, you can achieve data transmission rates of 9.6 Kbps to 12 Mbps.