User's Manual

Page 22
E Series Ethernet Radio – User Manual
Part D – System Planning and Design
Power Supply and Environmental
Considerations
General
When mounting the equipment, consideration should be given
to the environmental aspects of the site. The cabinet should be
positioned so that it is shaded from hot afternoon sun, or icy
cold wind. Whilst the radios are designed for harsh temperature
extremes, they will give a longer service life if operated in a more
stable temperature environment. In an industrial environment, the
radio modems should be isolated from excessive vibration, which
can destroy electronic components, joints, and crystals.
The cabinet should provide full protection from moisture, dust,
corrosive atmospheres, and residues from ants and small vermin
(which can be corrosive or conductive). The radio modem
will radiate heat from the in-built heatsink, and the higher the
transmitter duty cycle, the more heat will be radiated from the
heatsink. Ensure there is sufcient ventilation in the form of passive
or forced air circulation to ensure that the radio is able to maintain
quoted temperature limits.
Power Supply
The power supply should provide a clean, ltered DC source.
The ER45e modem is designed and calibrated to operate from
a 13.8VDC regulated supply, but will operate from 10-30 volts
(ltered) DC, or 11-16 volts For an EB45e or EH45e.
The power supply must be able to supply sufcient current to
provide clean ltered DC under the full current conditions of the
radio modem (i.e. When transmitting full RF power). See Section L
- Specications for more details of the power supply requirements.
Solar Applications
In solar or battery-backed installations, a battery management unit
should be tted to cut off power to the radio when battery levels
fall below the minimum voltage specication of the radio. In solar
applications, a solar regulation unit MUST ALSO be tted to ensure
that the radio (and battery) is protected from excessive voltage
under full sun conditions.
When calculating solar and battery capacity requirements, the
constant current consumption will be approximately equal to the
transmit current multiplied by the duty cycle of the transmitter, plus
the receive current multiplied by the (remaining) duty cycle of the
receiver.
The Tx/Rx duty cycle will be entirely dependent on the amount
of data being transmitted by the radio modem, unless the device
has been congured for continuous transmit, in which case the
constant current consumption will be equal to the transmit current
only (at 100% duty cycle).
Note: Operation below the minimum specied supply voltages
could result in poor radio performance. If the supply voltage falls
below 10Vdc the radio will shut down. Normal radio startup will not
occur until 10Vdc is supplied.
Site Earthing
Ensure that the chassis mounting plate, power supply (-) earth,
RTU terminal device, and lightning arrester, are all securely
earthed to a common ground point to which an earth stake is
attached. Please pay particular attention to 24Vdc PLC systems
using DC-DC converters to supply 13.8Vdc.
High Temperature Foldback
The ER45e will foldback the Transmit power by 6dBm if the internal
temperature sensor detects +70 degrees Celsius or greater. If the
remote is in foldback mode and the temperature is measured +67
degrees Celsius, the power will return to its original state.
Caution: There is NO readily serviceable internal fuse for
an EB45e or EH45e, and therefore they both MUST be
externally fused with a fuse and fuse holder (EB45e: 5
amp fast-blow fuse, EB45e(20W): 8 amp fast blow fuse,
EH45e: 1 amp slow blow fuse).
NOTE: The ER45e has a readily serviceable internal fuse.
Trio Part number: Part No. SM%FUSSQ5A)