The multiplexer has 6 Leds
plus 1 small red Led on the voltage regulator. It is important to
understand what determines its blinking as it can help in the
troubleshooting of the multiplexer or, most important, it can
indicate problems in the instrumentation or in connections between
the instruments and the multiplexer. The 4 Green Leds will blink
when an arriving Nmea 0183 sentence is detected on that port. Nmea
0183 Sentence Filtering affects this behaviour. If for example,
the Filtering String starts with the character 9, the Led will
never blink. If sentences are continuing arriving at an input
port, the rate of blink depends on the"skipping number" of the
Filtering String. This is equivalent to say that the Led will not
blink if the sequence is rejected by the filter. The Blue Led
indicates data arriving or data transmitted by the wifi ports.
Sentence Filtering on arriving sequences affects the blink of the
Led as explained above. The Red Led blinks when data is output on
P5 serial port. Sentence Filtering on P5 also affects the blink of
the Blue Led.
There are other meanings for the behaviour of the Leds. If we
force a normal Reset by pressing the "EN" button on the module
(equivalent to restart the multiplexer with the existent settings)
the Leds will blink momentarily and then rest. But it is not
always like that. If for example, if we had set the multiplexer to
connect to an external network and if that network does not exist
or we set a wrong password, we will see the 4 Green Leds and the
Blue Led to go ON simultaneously for about 1 second and then go
OFF simultaneously for about 1 second. This indicates a failure in
trying to connect to the external network. This will go on for
about 5 minutes when the multiplexer gives up to connect and will
eventually enter a sleep mode to save power depending on other
settings.
The Hard Reset is also signalled by the Leds. The Hard Reset is
forced by pressing and holding the "Boot" button for about 2
seconds and the multiplexer will restart with the Default Factory
Settings. In order to know that the 2 seconds have elapsed, we
notice that when the button is first pressed, the 4 Green and the
Blue Led go On. Then after 2 seconds they go Off. At this stage we
can release the button and the Reset will be taken.
Finally there is a special function of the Leds which is used to
test the operation of the output driver on P5 and the input
opto-couplers on P1 P2 P3 and P4. This is very technical and it is
described in the support Forum.