Analog Modules
4-134
Programmable Logic Controllers S7-300 Module Data
A5E00105505-03
Table 4-70 Scan Times in “Software Filter, 8 Channels” Mode
Programmed
Interference Frequency
Suppression
Channel Scan Time* Module Scan Time (All
Channels)
50 Hz 42 ms 84 ms
60 Hz 37 ms 74 ms
400 Hz 20 ms 40 ms
* Channel scan time = channel conversion time + 12 ms switching time to the other channel
in the channel group
Scan time in “Hardware Filter, 4 Channels” mode
In this mode, the module does not switch between the channels of the different
groups. As the module contains four analog/digital converters (ADC), all four of the
ADCs convert simultaneously for channels 0, 2, 4 and 6.
Scan time
Start analog conversion
(simultaneous)
K0 K2 K4 K6
Figure 4-44 Hardware filter 4 channels scan time
Scan time of the module
In 4-channel hardware filter mode, the channel conversion time including the
communication time of the analog input module SM 331; AI 8 x RTD is 10 ms. As
the module does not switch over between the channels in a group, the channel
scan time and the module scan time are the same: 10 ms.
Channel conversion time = channel scan time = module scan time = 10 ms