Siemens SIMATIC ET 200AL System Manual page 1477

High-speed analog modules
8.2 ST modules vs HS modules
Analog inputs with integrating methods can be used universally. Even though the cabling
must also be carefully designed with these analog inputs, the requirements are much less
than those for analog inputs with instantaneous value conversion due to their slower signal
acquisition that is basically immune to interference.
Figure 8-6
120
While an interference directly influences the value that is supplied to the application with
instantaneous value encryption, its influence is negligible for the integrating method.
Analog value processing
Function Manual, 06/2014, A5E03461439-AC