Siemens SIMATIC - Page 409

Analog modules
6.10 Analog input module SM 331; AI 8 x TC; (6ES7331-7PF11-0AB0)
S7-300 Module data
Manual, 06/2017, A5E00105505-AJ
409
Cycle time of module in 8-channel mode (software filter)
However, the channel conversion time is oriented on the programmed noise suppression.
The channel conversion time is 76 ms, including communication time, when you set an
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. As in "hardware filter, 8channel" mode, the
module has to change to the second channel of the group within a changeover time of 7 ms
using the Opto-MOS relays. The table below shows this correlation.
Table 6- 30 Cycle times in 8-channel mode (software filter)
Programmed noise suppression
Channel cycle time*
Module cycle time (all channels)
50 Hz
83 ms
166 ms
60 Hz 72 ms
144 ms
400 Hz
23 ms
46 ms
* Channel cycle time = channel conversion time +7 ms channel changeover time within the group
4-channel mode (hardware filter)
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 6-31 4-channel mode cycle time (hardware filter)
Cycle time of the module in 4-channel mode (hardware filter)
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, as the
module does not change between the channels of a group: 10 ms.
Channel conversion time = channel cycle time = module cycle time =
10 ms