Parameters
4.4 Flutter monitoring
4.4
Flutter monitoring
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 monitored period. This period is referred to as the monitoring
window. If signal characteristics like these occur, it is a sign that the sensors are faulty or that
there are instabilities from a process engineering viewpoint.
A monitoring window and a number of signal changes must be specified for the flutter
monitoring function to define the permissible changes of the input signal within the monitoring
window.
A prerequisite for the flutter monitoring function is that the input signal can be detected without
error.
Activation of flutter monitoring.
Activate flutter monitoring by setting an allowable number of input signal changes between 0
and 1 within the monitoring window. The number 0 deactivates the flutter monitoring function.
A flutter error detected by the flutter monitoring has a direct effect on the value status (QI).
Detecting a flutter error
Each input channel has a 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 diagnostics information is also entered and an incoming diagnostics interrupt is triggered.
You can evaluate and process the value status (QI) and the diagnostics 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
diagnostics interrupt is triggered. The value state of the current signal in the process image is
set to valid.
Note
Active flutter monitoring is reset if there is an error in the input signal (value status QI = 0).
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Digital Input Module DI 16xNAMUR HA (6DL1131-6TH00-0PH1)
Manual, 11/2017, A5E39293880-AB
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