Using The Selectable Input Filter To Provide Noise Rejection; Configuring The Input Filters For Rejecting Noise - Siemens SIMATIC S7-200 System Manual

CPU and Input/Output Configuration
6.2

Using the Selectable Input Filter to Provide Noise Rejection

The S7-200 CPUs allow you to select input filter that defines a delay time
(selectable from 0.2 ms to 12.8 ms) for some or all of the local digital input points.
(See Appendix A for information about your particular CPU.) As shown in
Figure 6-3, each delay specification applies to groups of four input points. This
delay helps to filter noise on the input wiring that could cause inadvertent changes
to the states of the inputs.
The input filter is part of the CPU configuration data that is downloaded and stored
in the CPU memory. To configure the delay times for the input filter, use the menu
command View > System Block and click on the Input Filters tab.
System Block
Analog Input Filters
Port(s)
Configuration parameters must be downloaded before they take effect.
Not all PLC types support every System Block option. Press F1 to see
which options are supported by each PLC.
Figure 6-3
6-4
Pulse Catch Bits
Retentive Ranges Password
I0.0 - I0.3 6.40 ms
I0.4 - I0.7 6.40 ms
I1.0 - I1.3 6.40 ms
I1.4 - I1.5 6.40 ms

Configuring the Input Filters for Rejecting Noise

Background Time
Output Table Input Filters
Defaults
OK
S7-200 Programmable Controller System Manual
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