Flutter Monitoring - Siemens SIMATIC ET 200iSP Operating Instructions Manual

12.6.3

Flutter monitoring

Description
Chatter monitoring is a process control function for digital input signals. It detects and reports
signal characteristics that are unusual from a process engineering viewpoint, such as the input
signal fluctuating too frequently between "0" and "1". 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.
Activating chatter monitoring
You activate chatter monitoring by setting the number of signal changes for chatter monitoring
to a value other than zero.
Detecting unusual signal patterns
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
more often within the monitoring window than the set number of signal changes, a chatter error
is detected. If no chatter error is detected within the monitoring window, the monitoring window
is started again at the next signal change.
Reporting a chatter error
If a chatter error has occurred, the current signal status is entered in the process image and
the value of the signal is set to "invalid". A chatter error is also entered as diagnostic information,
triggering an incoming diagnostic interrupt.
You must evaluate and process the status of the value and the diagnostic information in the
user program.
Resetting a flutter error
If no further chattering of the input signal is detected within three monitoring windows, the
diagnostic entry is removed and an outgoing diagnostic interrupt is triggered. The status of the
value of the current signal in the process image is set to "valid".
ET 200iSP
Operating Instructions, 11/2017, A5E00247483-07
12.6 Description of the parameters of the digital electronic modules
Digital electronic modules
265