Siemens SIMATIC S5-95F Manual page 42

Design, Functions and Operation
Length of the Shift Register
The total length of the shift register is obtained from the sum of the data bits of all plugged-in
modules and of the empty slots. The check bit is not counted.
You must know the length of the shift register to be able to determine the data cycle time. Data
cycle time is 25 µs x number of data bits.
Table 2-2. Number of Bits per Module in the Shift Register
Failsafe modules
Digital input module
Digital output module
Non-failsafe modules
Digital input/output modules, 8-channel
Digital input and output module,16DI/16DQ
Analog modules for each switched channel
CP 521 SI communication module
Vacant slot
2-10
Plugged-in Module Number of Data Bits
8
8
8
16
16
64
4
EWA 4NEB 812 6210-02
S5-95F