5.1.3
Transmitter and receiver failures
Transmission and reception of RF messages is signaled by flashing of yellow ”TXA” / ”RXA” LEDs and red ”ALR”
LED on the module front panel. The ”TXA” LED blinks when a radio message is transmitted, the ”RXA” LED
blinks when a radio-message is received. When transmitting of message is postponed by anti-collision system, the
red ”ALR” LED is flashing.
If the module is powered by correct voltage, the module communicates through the configuration port, responds
to the configuration commands but the radio-messages from the module are still not received steadily, the possible
reason of the trouble can be a failure of transmitting or receiving of radio signal. The typical indication of trans-
mitting or receiving failures is state of
”
partial” functionality, that have following external signs:
•
the module transfers data only from certain elements of the radio-network, data from other elements are not
transferred;
•
certain elements of the network do not receive data from the module;
•
data from certain elements of the network are incorrect or incomplete;
•
there are numerous breakdowns in the data communication (sometimes the data pass through the module,
sometimes not).
All above described troubles could have on common ground, which is unreliability of radio-communication caused
by one of these reasons:
•
incorrect setting of transmitter parameters, mainly frequency channel, maximum number of re-translations,
or transmitting power;
•
permanent or occasional blocking of radio signal caused by construction works or any construction changes
within the premises, or by operation around the installation site (moving of machines, cars, etc.);
•
permanent, periodical or occasional interference (jamming) of radio signal from external source (another radio
system in the same frequency band, or industrial disturbance).
•
low level of transmitting signal caused by wrong setting or failure of transmitter;
•
low level of receiving signal caused by wrong setting or failure of receiver;
•
low level of transmitting and receiving signal caused by damage of antenna or antenna cable (if external
antenna used).
If above described indications of unreliable radio-communication become evident, proceed with troubleshooting of
the malfunctioning in following steps:
•
visually check surrounding of the installation site to find out if there are any changes that can influence radio
signal (e.g. new objects, things, machines...). If there are such negative circumstances, solve the trouble by
reorganization of the object or by redesign of radio network;
•
visually check an external antenna and antenna cable (if used), possibly replace these elements for the spare
ones with proven functionality;
•
check correctness of module settings, especially setting of radio parameters as described in paragraph
and
perform the check of module overall functionality as described in paragraph
•
if there are breakdowns in communication with some specific element of the network, check functionality of
that element according to the respective documentation;
•
replace the module according to the paragraph
and perform the setting and check of overall functionality
off the new module after that;
•
if the module is not properly working even after its replacement for proven device and equipment, the trouble
can be caused by local interference (jamming) from external source. Another possible reason could be an
unsuitable setting of some configuration parameter that has not been discovered. In this case ask for your
supplier, producer, or other experienced person for some form of assistance.
Appropriate level of transmitting power can be checked by comparing of its signal strength with the reference
signal from another module (modules) under comparable circumstances, for example with using of signal analyzer
or testing receiver placed to the suitable spot. If the signal strength is similar to the signal of reference transmitter,
then the module’s transmitting power is adequate, and the reason of troubles could be in insufficient signal strength
on the receiving side. Attenuation of the signal can be caused by making of some change in module installation
site (e.g. turning of antenna or placing of some object nearby, installation of iron bars, rack or shelfs...) or similar
changes in the installation site of receiver (GateWay). This kind of troubles can be solved by redesign of the radio
network in order to secure sufficient signal reception (that means changing of antenna for better type, moving of
antenna or whole device etc.).
Presence of radio-disturbance is signaled by frequent (or permanent) flashing of red ”ALR” LED.
WM868-MS-LP-H
27
