Siemens SIMATIC Equipment Manual page 22

Address space for configuration as 1 x 16-channel DI 16x24VDC MSI
With the configuration 1 x 16-channel I/O device (module-internal shared input, MSI), the
channels 0 to 15 (incl. value status) of the I/O device are copied into a submodule. Channels
0 to 15 (incl. value status) are then available with identical values in the submodule. You can
assign the basic submodule and the MSI submodule to two different IO controllers. Each
IO controller has read access to the same channels.
Value status (Quality Information,QI)
The meaning of the value status depends on the submodule on which it occurs.
For the first submodule (=basic submodule), the value status 0 indicates: The module detects
that an error is pending at the channel and that the value is faulty.
For the 2nd submodule (=MSI submodule), the value status 0 indicates that the value is
incorrect or the basic submodule has not yet been assigned parameters (not ready).
The figure below shows the assignment of the address space with submodule 1, 2 and the
value status.
Figure 4-3
I/O device digital inputs DI 16x24VDC M12-L 8xM12 (6ES7141-6BH00-0BB0)
Equipment Manual, 06/2021, A5E46570510-AB
Address space for configuration as 1 x 16-channel DI 16x24VDC MSI with value status
Parameters/address space
4.3 Address space
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