Siemens SIMATIC Manual page 326

Analog modules
6.4 Analog input module SM 331; AI 8 x 16 Bit; (6ES7331-7NF10-0AB0)
Cycle time of module in 8-channel mode
The channel conversion time is based on the programmed noise suppression. The channel
conversion time is 76 ms, including communication time, at a set interference frequency of
50 Hz. The channel conversion time is 65 ms when you set an interference frequency of
60 Hz. You can reduce channel conversion times to 16 ms by setting an interference
frequency of 400 Hz. When you set 50, 60 and 400 Hz , the channel conversion time
amounts to 88 ms. The module then has to switch to a different channel of the group by
means of the OptoMOS relay. Opto-MOS relays require 7 ms for switching and settling. The
following table shows this relationship.
Table 6- 12
Interference frequency (Hz)
50
60
400
50/60/400
4-channel operating mode
In this mode, the module does not change between the channels of the groups. The four
ADCs of the module simultaneously convert the channels 0, 2, 4 and 6.
Figure 6-6
Module cycle time
The converted value settles to 100% within 80 ms and is updated every 10 ms when 4-
channel mode is set. The channel and module cycle times are always identical, because the
module does not change between the channels of a group: 10 ms.
Channel conversion time = channel cycle time = module cycle time = 10 ms
326
Cycle times in 8-channel mode
Channel cycle time (ms)
83
72
23
95
4-channel mode cycle time
Module cycle time
(all channels)
166
144
46
190
S7-300 Module data
Manual, 06/2017, A5E00105505-AJ