Casella CEL Automatic weather station - Manual (Page 16)

Battery = female type). The battery is wired to the Sensus Data Logger’s “Batt”
terminals (‘B+’ and ‘B-’ respectively). The Sensus will disconnect the battery
from the load when its terminal voltage falls below approximately 10.5 V.
2.7.5 Conserving Battery Power
If an automatic weather station is not going to be used for an extended period of
time, it is advisable to remove the inline fuse from the back up or solar battery.
This prevents the lead acid battery from deep discharging, which can
permanently damage the battery.
During long periods of non use the battery may require regular ‘top up’
charging using a conventional 12 volt lead acid battery charger.
2.8 UHF / VHF Radio Telemetry Option
The UHF/VHF transmitter is located within the station enclosure and is connected
to the RS232 and Power connectors of the Sensus logger. For specific wiring and
technical details, please refer to the “Calibration & System Details” section of
this handbook.
A female “N” type bulkhead connector is generally fitted to the base of
the automatic weather station enclosure and should be interconnected to the
antenna using low loss coaxial cable.
The transmitting antenna must be located away from large metallic
surfaces and should preferably have a clear line of sight to the receiving
antenna. The receiving antenna should be located away from potential sources
of electrical noise.
Antennas are secured to the frame or supporting structure using ‘U’
bolt clamping assemblies. The receiver’s data output signal should be connected
to the appropriate serial port on the P.C using supplied cable.
Unless otherwise specified by the customer, the transmitter supplied
will be tuned for use on one of the channels in the licence exempt section of the
U.H.F. band, between 458.500 MHz and 458.800 MHz. with 12.5 KHz channel
spacing. Demands on the radio spectrum are intense and with the exception of
this small licence exempt section, a licence from the Radiocommunications
Agency* will be required.
We keep a record of the location of all the transmitters we have
supplied and we will try to ensure that the frequency chosen will not conflict with
nearby systems supplied by Casella Ltd. We cannot however guarantee that the
frequency chosen will not be occupied by other users or that equipment
previously supplied by us has not been moved into your area.
Customers outside the U.K. will be required to specify the frequency to
be used. It is the responsibility of the customer to ensure that all their local
regulations for the use of radio transmitting equipment are complied with. If the
frequency chosen proves to be unsuitable, the customer will be liable for the
cost of returning the transmitter and receiver to the manufacturer for re-tuning
to another channel.
*Radiocommunications Agency
South Quay Three
189 Marsh Wall
London E14 9SX
Telex: 261969 RASQ3 G
24 Hour Enquiry Service: 0171 211 0211
Fax: 0171 211 0118
Page 16 of 34
Automatic Weather Station
Assembly & Commissioning Handbook