Flutter Monitoring; Useful Information About Flutter Monitoring - Siemens SIMATIC ET 200SP HA Equipment Manual

6.5

Flutter monitoring

6.5.1

Useful information about flutter monitoring

Flutter monitoring and its functions are described below.
Description
Flutter monitoring is a process control function for digital input signals. It detects and reports
unusual process control signal patterns, for example, an excessive number of input signal
changes between 0 and 1 within a specified period. This period is referred to as the monitoring
window. If signal characteristics like these occur, it is a sign that the encoders are faulty, or that
there are instabilities from a process engineering viewpoint.
Detecting a flutter error
A flutter error detected by the flutter monitoring has a direct effect on the value status (QI).
Each input channel has a configured monitoring window that has been assigned parameters.
The monitoring window is started the first time the input signal changes. If the input signal
changes within the monitoring window more often than the configured number of signal
changes, this is recognized as a flutter error. If no flutter error is detected within the monitoring
window, the window is restarted at the next signal change.
Reporting a flutter error
If a flutter error occurs, the current signal state is entered in the process image, and the value
status of the signal is set to invalid (QI = 0). When flutter error diagnostics is enabled, the flutter
error diagnostic information is also entered, triggering an incoming diagnostic interrupt.
You can evaluate and process the value status (QI) and the diagnostic information in the user
program.
Resetting a flutter error
If no further flutter of the input signal is detected within three monitoring windows, an outgoing
diagnostic interrupt is triggered. The value state of the current signal in the process image is set
to valid.
Note
Active flutter monitoring is canceled if there is an error in the input signal (value status QI = 0).
DI 16xNAMUR HA
Equipment Manual, 08/2019, A5E39293880-AD
Parameters
6.5 Flutter monitoring
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