Siemens SIMATIC S7-1500 Configuration Manual page 7

2 Fundamentals on "Shared Device"
Example:
A CPU supports send clocks of 0.25 ms or higher. A configured IO device also
supports send clocks of 0.25 ms or higher, another supports send clocks of 1 ms or
higher. In this case, you have the possibility to set a short send clock of 0.25 ms for
the CPU. The CPU operates the "slow" IO device with a send clock of 1 ms, for
example.
Rules for the configuration
For the use of the "Shared Device" function, the following rules apply:

IO controllers that use the "Shared Device", are created in different projects. In
every project, you must ensure that the "Shared Device" is configured the
same at every station. Only one IO controller at a time may have access to a
module. Inconsistencies within the configuration lead to a failure of the "Shared
Device".

I/O addresses of a module are editable only when it is assigned to the IO
controller in the same project.

The "Shared Device" must have the same IP parameters and the same device
name in every project.

The send clock must be the same for all IO controllers that have access to the
"Shared Device".

The S7 subnet ID of the subnet to which the "Shared Device" is connected
must be the same in all projects.

The following functions are enabled only when the PROFINET interface of the
"Shared Device" is assigned to the local IO controller:
–
IRT operation
–
Prioritized initialization
–
Configuring the port properties
Boundary conditions
Because a shared device configuration is distributed over several projects, the
following boundary conditions apply:

In the address overview of every IO controller that has access to a "Shared
Device", the addresses of modules that are not assigned to this IO controller
are missing.

During the consistency check, the unassigned modules are not included into
the quantity structure calculation for the "Shared Device". Therefore, you must
ensure that the maximum number of modules or the maximum number of cyclic
IO data for the "Shared Device" is not exceeded. Information on the maximum
quantity structures can be found in the documentation of the devices used.

Configuration errors like assigning a module to several IO controllers will not
be recognized by STEP 7.

CPUs that are loaded with a "Shared Device" configuration are unable to
detect that the IO device is a "Shared Device". Modules that are assigned to
other IO controllers and therefore other CPUs, are missing in the loaded
configuration. Therefore, these modules are neither displayed in the CPU web
server, nor in the CPU display.
SharedDeviceKonfig
Entry ID: 109741600, V1.0, 11/2016
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