Siemens Simatic S7-300 CPU 31xC and CPU 31x S7-300 - Manual (Page 148)

Technical data of CPU 31xC
6.6 Technical data of the integrated I/O
CPU 31xC and CPU 31x, Technical data
6-38
Manual, Edition 08/2004, A5E00105475-05
Value
1
Value
2
Value
3
. . .
Value
16
Value
17
Value
1
Value
2
Value
3
. . .
Value
16
Value
17
1.05 ms 1.05 ms 1.05 ms 1.05 ms 1.05 ms
1.05 ms 1.05 ms 1.05 ms 1.05 ms 1.05 ms
Example of a 60-Hz parasitic frequency suppression (integration time corresponds to 16.7 ms)
1 averaged measured value
1 averaged measured value
Cycle 1
Cycle 2
Figure 6-6 60 Hz interference suppression
Note
If the interference frequency is not 50/60 Hz or a multiple thereof, the input signal must be
filtered externally.
In this case, 400 Hz frequency suppression must be configured for the respective input. This
is equivalent to a "Deactivation" of the software filter.
Inputs not connected
The three inputs of a current/voltage analog output channel that is not connected should be
bypasses and connected to M
ANA
(pin 20 of the front connector). This ensures maximum
interference resistance for these analog inputs.
Outputs not connected
In order to disconnect unused analog outputs from power, you must disable and leave them
open during parameter assignment with STEP 7.
Reference
Details (visualization and processing of analog values, for example) are found in chapter 4 of
the Module Data Reference Manual.