Specifications

CPU and Input/Output Configuration
6-9
S7-200 Programmable Controller System Manual
C79000-G7076-C233-01
6.5 Analog Input Filter
With the CPU 222 and CPU 224, you can select software filtering on individual
analog inputs. The filtered value is the average value of the sum of a preselected
number of samples of the analog input. The filter specification (number of samples
and dead band) is the same for all analog inputs for which filtering is enabled.
The filter has a fast response feature to allow large changes to be quickly reflected
in the filter value. The filter makes a step function change to the latest analog input
value when the input exceeds a specified change from the average value. This
change is called the dead band and is specified in counts of the digital value of the
analog input.
Note
Be sure that analog filtering is appropriate for your application. Otherwise, disable
the analog input filter using the STEP 7-Micro/WIN 32 configuration screen shown
in Figure 6-9.
To access the analog input filter, select the menu command View > System Block
and click on the Analog Input Filters tab. Select the analog inputs that you want to
filter and click “OK.” See Figure 6-9. The default STEP 7-Micro/WIN 32
configuration is enabled for all inputs.
System Block
OK Cancel
Configuration parameters must be downloaded before they take effect.
Apply
PasswordPort(s) Retentive Ranges
Analog Input Filters
Output Table Input Filters
Pulse Catch Bits
Background Time
AIW 14- 0
AIW 30 - 16
Select which Analog Inputs to filter
14
30
12
28
10
26
8
24
6
22
4
20
2
18
0
16
Number of samples Deadband (16 - 4080)
0 = No Deadband
64
320
Not all PLC types support every System Block option. Press F1 to see
which options are supported by each PLC.
Defaults
Figure 6-9 Analog Input Filter