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ComBricks User Manual v6.4.0 | January 18| © PROCENTEC 125/219
12.2.2 PA oscilloscope images
The PA module has an integrated oscilloscope to measure the signal quality of the telegrams. The oscilloscope
has an interface with the web server to display the signals from the devices which are connected to its channel.
After opening the web page, all oscilloscope signals are displayed and updated live (see Fig. 81). By default one
scope image is updated every second. This can be adjusted in the General Config page (see paragraph 4.4).
Click the button ‘Reset oscilloscope images’ to delete all scope images from memory. If the red ‘ AMP ’ LED on
the PA module was on, this will be switched off. If the values are still not good, the LED will remain on.
12.2.3 PA Bar Graph
The Bar Graph illustrates the average AC signal strength from all available connected devices connected to the
PA segment. It is a helpful utility to get an impression of the overall signal quality of the network (see
Fig. 82 ).
The average amplitude should be around 750mV. When there are bus problems the Bar graph will display
different Voltage levels and the color of the bars will change if the minimum or maximum level has been
reached. These levels can be adjusted in the
‘ Oscilloscope Config ’ menu (see chapter 12.2.5).
Fig. 82 - Bargraph image for PA
In the above example the amplitude is too high due to missing termination on one side.
Normally the amplitude should be between 750 and 1000 mV.
Amplitude too high
Select the slot of
the PA module
Select the slot of
the PA module
Good AC signal
quality
Fig. 81 - Oscilloscope images