Hardware Filter 4 Channels Scan Time - Siemens SIMATIC S7-300 Reference Manual

Analog Modules
Scan time of the module
In the 8-channel software filter mode of analog input module SM331; AI 8 x TC, the
channel conversion time is guided by the interference frequency set. When you set
an interference frequency of 50 Hz, the channel conversion time including
communication time is 76 ms. When you set an interference frequency of 60 Hz,
the channel conversion time is 65 ms. When you set an interference frequency of
400 Hz, the channel conversion time is reduced to 16 ms. As with 8-channel
hardware filter mode, the module must be switched over by means of opto MOS
relays with a switchover time of 7 ms to the other channel of the group. Table 4-75
shows the scan time of the module at a certain interference frequency.
Table 4-75 Scan Times in "Software Filter, 8 Channels" Mode
Interference Frequency
Channel scan time = channel conversion time + 7 ms switching time to the other channel
*
in the channel group
"Hardware filter 4 channels" mode
In 4-channel hardware filter mode, the analog input module SM331; AI 8 x TC does
not switch over between the channels of the individual groups. As the module
contains four analog/digital converters (ADC), all four of the ADCs convert
simultaneously for channels 0, 2, 4 and 6.
Figure 4-48
4-148
Programmed
Suppression
50 Hz
60 Hz
400 Hz
Start analog conversion
(simultaneous)
K0 K2

Hardware filter 4 channels scan time

Channel Scan Time*
83 ms
72 ms
23 ms
K4 K6
Programmable Logic Controllers S7-300 Module Data
Module Scan Time (All
Channels)
166 ms
144 ms
46 ms
Scan time
A5E00105505-03