GEA Grasso, Manual

Page: 102 / 166

Grasso
Refrigeration Division
GRASSO SYSTEM CONTROL
Kap.5 - 4 638660E_chapter5.doc 01.2003/0
5.3 Extended data communication (interfaces)
The GSC is equipped with an MPI interface as a standard.
This interface can be used to connect up to 32 users to each other.
As this interface is an internal Siemens interface with multi-point capability, it can only be used between Siemens
controls (S7).
The MPI interface can be operated with a maximum transmission speed of 187.5 kBit/s, whereby the distance
between 2 adjacent users must not exceed maximum 50 m.
As an option, the GSC can also be fitted with a Profibus DP coupler (Master/Slave method).
This bus protocol is standardised and can also be interpreted by other controls.
With a Profibus, up to 128 users can be operated together with a maximum transmission speed of 12 Mbit/s,
whereby the maximum total length is between 100 m and 1200 m. The maximum total length of the bus system
is dependent on the number of users and the transmission speed.
)
The precise bus structure and the transmission and receiving data protocol are described in more detail
in the “MPI and Profibus” manual.
5.3.1 Explanation of the MPI
To set up a network with MPI, all the users must be connected to each other with a bus cable.
As the MPI interface is fed to the GSC on a 9-pin sub-D jack, suitable cable connectors are required.
Figure 5.1: Overview of the interfaces, memory card placing and battery position
MPI I/O interface Memory Card IM Battery
To access the battery
remove this cover!