Siemens SIMATIC Manual page 308

Analog modules
6.3 Analog input module SM 331; AI 8 x 16 bit; (6ES7331-7NF00-0AB0)
High-speed update of measured values
A high-speed update of measured values at two channels of a channel group is three times
compared to the activation of several channel groups.
Example: When channels 0 and 1 are active with 2.5 ms filtering, both channels return new
measured values to the PLC at intervals of 10 ms. (with other settings, the refresh rate is
equivalent to the filter setting.)
High-speed update of measured values is only possible if both channels of channel group 0
and 1 are active, that is, the "measuring type" parameter is set. However, only one of the two
channel groups 0 or 1 may be active (not concurrently active.)
Terminal assignment
The diagrams below show various wiring options
308
S7-300 Module data
Manual, 06/2017, A5E00105505-AJ