Different CPUs with integral PROFIBUS DP interfaces are available for different performance ranges. Depending on type, they are also available with integral PROFINET interface. The PROFIBUS interface enables the connection of up to 125 PROFIBUS DP slaves. Up to 256 PROFINET IO devices can be connected to the PROFINET interface. All CPUs of the SIMATIC S7-400 can handle extremely large configurations. In addition, several CPUs can work together in multicomputing in one central controller to increase performance. The CPUs enable short machine cycle times by means of their efficient processing speed and deterministic response times.
Signal modules (SMs) for digital (DI/DO) and analog (AI/AO) input/output
Communications processors (CPs), e.g. for bus connection and point-to-point connections
Function modules (FMs):
The specialists for demanding tasks such as counting, positioning and cam control.
The following can also be used depending on requirements:
Interface modules (IMs):
for connecting central controllers and expansion units. The central controller of the SIMATIC S7-400 can be operated with up to 21 expansion units.
SIMATIC S5 modules:
All input/output modules of the SIMATIC S5-115U/-135U/-155U can be addressed in the relevant SIMATIC S5 expansion units. In addition, the use of certain IP and WF modules of the SIMATIC S5 is possible both in S5 EUs and direct in the CC (using adapter casing).
Expansion
If users require more than one central controller for their applications, the S7-400 can be expanded:
Max. 21 expansion units:
Up to 21 expansion units (EUs) can be connected to the central controller (CC).
Connection of the interface modules (IMs):
The CC and EUs are connected via send and receive IMs. Send IMs are plugged into the CC, and the associated receive IMs are plugged into the downstream EUs. Up to 6 send IMs can be plugged into the CC (of which up to 2 with 5-V transfer), and up to 1 receive IM can be plugged into the EUs. Each send IM has 2 interfaces for connecting one line each. Up to 4 EUs (without 5-V transfer) or 1 EU (with 5-V transfer) can be connected to each interface of a send IM.
Fixed slot for power supply modules:
Power supply modules must always be plugged in on the extreme left in the CC and EUs.
Restricted data exchange via C bus:
Data exchange via the C bus only between the CC and six EUs (EU 1 to EU 6).
Central expansion:
To be recommended for smaller setups or control cabinets direct at the machine. The 5-V power can optionally also be supplied.
Max. distance between CC and the last EU of a line: 1.5 m with 5 V transfer, 3 m without 5 V transfer.
Distributed expansion with EUs:
Recommended in plants covering a large area where several EUs are located at individual locations. Up to S7-400 EUs or SIMATIC S5 EUs can be used.
Max. distance between CC and the last EU of a line: approx. 100 m with S7 EU, 600 m with S5 EU.
Note For distributed connection of S5 expansion units to an S7-400:
The IM 463-2 can be used in the CC of the S7-400, and an IM 314 is used in the S5 EU. The following S5 EUs can be connected to an S7-400:
EG 183U
EG 185U
EG 186U
ER 701-2
ER 701-3
Connection type
Maximum (total) cable length
Local link with 5-V transfer via IM 460-1 and IM 461-1
1.5 m
Local link without 5-V transfer via IM 460-0 and IM 461-0
5 m
Remote link via IM 460-3 and IM 461-3
102.25 m
Remote link via IM 460-4 and IM 461-4
605 m
Distributed expansion with ET 200:
recommended for plants covering extremely large areas. A line with up to 125 bus nodes can be connected via the PROFIBUS DP interface of a CPU. Maximum distance between the CC and last node on the line: 23 km (with fiber optic cable).
S7-400 communication
The SIMATIC S7-400 has different communication options:
Combined multipoint interface and DP master, integrated into all CPUs:
For the simultaneous connection of PGs/PCs, HMI systems, S7-200 and S7-300 systems and other S7-400 systems.
Additional PROFIBUS DP interface, integrated into several CPUs for cost-effective connection of distributed I/O systems, e.g. ET 200.
Integral PROFINET interface on PROFINET CPUs for connections to distributed I/O systems, or communication with other controllers and PC systems.
Communications processors for connecting to the bus systems PROFIBUS und Industrial Ethernet.
Communications processors for the powerful point-to-point connections.
Process communication via PROFIBUS DP
The SIMATIC S7-400 can be connected as master with PROFIBUS DP via the integral PROFIBUS DP interface of the S7-400-CPU (optional).
The following can be connected as masters on PROFIBUS DP:
SIMATIC S7-400 (CPUs, CP 443-5)
SIMATIC S7-300 (CPUs, CP 342-5 DP or CP 343-5)
SIMATIC C7 (via C7 with PROFIBUS DP interface or PROFIBUS DP CPs)
Although PG/PCs with STEP 7 or OPs are masters on the bus, they only use the PG and OP functions that also run in part via PROFIBUS DP.
The following can be connected as slaves:
Distributed I/O devices, e.g. ET 200
Field devices
SIMATIC S7-200, S7-300
C7-633/P DP, C7-633 DP, C7-634/P DP, C7-634 DP, C7-626 DP
SIMATIC S7-400 (via CP 443-5 only)
Data communication via multipoint interface (MPI)
The multipoint interface (MPI) is a communication interface integrated into the CPUs of the SIMATIC S7-400.
It is used for:
Programming and parameterization
HMI
Establishing simple network topologies involving equal communication partners
Variable connection options:
The MPI enables simultaneous connection of up to 32 nodes: