X20 system modules • Other functions • X20CM8281
X20 system User's Manual 3.10
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4.26.3.10.5.1 Analog input register
Name:
AnalogInput01
This register is used to indicate the analog input value depending on the configured operating mode.
Data type
Value
Input signal:
-32768 to 32767
Voltage signal -10 to 10 VDC
0 to 32767
Current signal 0 to 20 mA
INT
0 to 32767
Current signal 4 mA to 20 mA
4.26.3.10.5.2 Input filter
This module is equipped with a configurable input filter. The minimum cycle time must be >400 μs. Filtering is
disabled for shorter cycle times.
If the input filter is active, then the scan rate for the channel is measured in ms. The conversion takes place
asynchronously to the network cycle.
Input ramp limitation
Input ramp limitation can only take place when a filter is used; the input ramp is limited before filtering takes place.
The amount the input value changes is checked to make sure that specified limits are not exceeded. If the values
are exceeded, the adjusted input value is equal to the old value ± the limit value.
Configurable limit values:
Value
Limit value
0
The input value is used without limitation.
1
0x3FFF = 16383
2
0x1FFF = 8191
3
0x0FFF = 4095
4
0x07FF = 2047
5
0x03FF = 1023
6
0x01FF = 511
7
0x00FF = 255
Input ramp limitation is well suited for suppressing disturbances (spikes). The following examples show the function
of the input ramp limitation based on an input jump and a disturbance.
Example 1
The input value jumps from 8,000 to 17,000. The diagram shows the adjusted input value with the following settings:
Input ramp limitation = 4 = 0x07FF = 2047
Filter level = 2
0
8000
17000
t [ms]
Input jump
1
2
3
4
5
6
7
8
Input value
Internally adjusted input value before filtering
Figure 743: Adjusted input value for input jump
