User manual

105G Wirless Gateway User Manual
Page 139 ©February 2009
(c) Show Signal Strength
This option allows measurement of radio path between two locations. This is done by the display
of the received radio signal strength at the connected 105G. With no transmitted signal from the
other site, the display will show the strength of the background noise, which is normally between
-100 and -130 dBm. At the other site, the transmitter may be turned on (select “e” at the other
105G, or “Tone Reversals” if the other module is a 105U). The display will now show the
received radio signal from the other transmitter.
The display will initially show the background noise of the radio band. Determine the
approximate average of the noise level. The remote unit may then be set up for tone reversals
(refer below). Determine the approximate average of the received signal strength. It is normal
for the measured values to continually change - the radios are continually changing frequency.
Calculate the best average for both the noise and signal.
For reliable operation, the average signal strength should be better than –98dBm (that is, -
90dBm, not –100dBm) provided the average background noise is less than –108dBm (between –
108 and –130 dBm). If the average noise is greater than –108, the difference between the noise
level and the transmitter signal should be at least 10dB for reliable operation. For example, if
the average noise level is -101dBm, then a transmitter signal of better than -91dBm is required
for reliable operation.
Note the RSSI (received signal strength indication) of a received message is also stored in the
database registers when the module is online - refer to section 2.5.1
e) Tone Reversals
If you select this option, the module will continuously transmit - you can use this feature for
radio tests. Note that if you are powering the module from a battery only, the battery will be
discharged quickly.
f) Initialize and Enter Debug Menu
This option will put the 105G in online debug mode. In online mode, the module will initialize
the radio driver and go online to the radio network. Where possible, the fieldbus driver will also
be initialized (i.e. for Ethernet, Profibus, Modbus Plus, and DeviceNet) – for Modbus, DF1, and
ELPRO Serial Driver the fieldbus driver will be disabled so that the serial port can be used for
diagnostics. Note: before going online, the 105G must complete any “startup polls” that are
configured – this may take some time depending on how many polls are configured.
x) Exit
The module will restart via its normal power-up and initialization sequence, and resume its
normal operation mode. Select “Stop Terminal” to shut down the terminal and close the com
port.
6.2.2 Online Diagnostics
The online diagnostics menu enables the radio protocol driver and the fieldbus protocol driver
(where possible) to provide online diagnostic information while the module is running. When the
configured protocol driver uses the shared RS232/485 port (i.e. Modbus, DF1, or ELPRO Serial
Driver), the online diagnostics must disable the serial protocol driver since the same serial port
must be made available for diagnostics.