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C7 6xx -- Product information -- Determining performance and quantity frameworks
What restrictions are there for active jobs when communicating with SFC 58 / SFC 59 and SFB 52 / SFB 53 via PROFIBUS DP and PROFINET IO?
How many connection resources can be managed by the C7-CPU or the C7-OP?
C7 6xx -- Product information -- Background and system information
Which external storage media can you use with the current SIMATIC panels and which memory card interfaces do they have?
The C7 6xx complete devices are to be discontinued in October 2010 – what are their successors?
How do you display ALARM_S or ALARM_D messages with process values (so-called associated values) on a WinCC flexible operator panel?
Which connector cables are available for connecting to SIMATIC Panels?
How many connection resources can be managed by the C7-CPU or the C7-OP?
Which GSD file do you need for a C7 Complete Device?
Which software do you need for the C7-621 module (with integrated AS interface master)?
How can you obtain an overview of the memory concept of SIMATIC S7-300 CPUs and C7 devices?
Why does the retentivity behavior of the S7-300 CPUs and C7 devices without MMC (Micro Memory Card) influence the contents of the variables?
Retentivity behavior of S7-300 CPU 31x and complete devices C7-6xx with MMC
Overview of components integrated in a C7 complete system
How many connection resources can be managed by the C7-CPU or the C7-OP?
Part number:

Every communication connection needs connection resources on the respective device:

  • for the PG-communication
  • for the OP-communication
  • for the S7-basis communication

1. C7-CPU
In principle several connections can be managed by the C7 CPU. These are split up as follows:

  • A connection is reserved for the PG. It can't be used for other purposes. Consequently it is guaranteed at any time, that a (service-) PG can be connected in case of an error.
  • A second connection is reserved for the C7-OP. 
  • Furthermore "spare" connections are available for user-defined use (view table 1).

The communication modes "Global data" (GD) and "Decentralized periphery" (DP) do not use the connection resources.

2. C7-OP
A C7-OP can manage several connection resources. These are split up as follows:

  • A connection of the C7-OP is reserved for the ("internal") C7 CPU (exception C7 613).
  • Further connections are at the users disposal, which can be assigned to user-defined "external" controllers. This might be further C7, S7 300 or S7 400 controllers.

Assign the connection resources in the configuration environment of ProTool or ProTool/Lite.
C7 device

Number of CPU connections

Number of OP connections


C7-635 12 4
C7-636 16 6
Table 1: Maximum possible communication connections on a C7 device 

A CP 342-5 can be used in order to increase the number communication stations (connections) in the C7-CPU.

More information on this topic area is available in

  • the manual on "Communication with SIMATIC" in Entry ID 1254686.
  • the manual on "SIMATIC Complete Device C7-613" in Entry ID 13125532.
  • the manual on "SIMATIC Complete Device C7-635" in Entry ID 11559312.
  • the manual on "SIMATIC Complete Device C7-636" in Entry ID 18230904

 Entry ID:37112   Date:2006-07-07 
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