Appendix Title
24
Use the current consumption numbers in the Specifications section to calculate
the power consumption of your modem and the size of battery, solar panel and
charging regulator that you will require.
10.2
Switched Power
In order to reduce the current consumption of the modem, power to the modem
can be switched on and off at different times or under certain circumstances by
utilizing the Switched 12V supply or by using an external relay circuit. Details
of an external relay circuit can be found in the installation section of your data
logger manual. Common configurations include having the modem switch on
for 10 minutes per hour or switching the modem off during night time in solar
powered systems.
Switched 12V power can be supplied by the data logger on its SW12 channel.
Note that this output is controlled by the datalogger program and is disabled by
default – a modem plugged into an unconfigured data logger’s SW12 will be
unpowered. In order to use SW12, the logger’s program must be written to
switch the power on and off using the SW12() instruction in CRBasic.
10.2.1
SW12 and Remote Program Upload
Exercise caution when loading new programs over the
modem link if the modem is powered by SW12. If the
new program is not properly configured, this can cause
the modem to lose power and the station may no longer
be contactable.
One good way to avoid this situation is to insert a SW12(1) statement in your
CRBasic program between the BeginProg and Scan() statements – this will
ensure that one of the first things the logger will do after receiving its new
program is power on the modem.
A default.crx file can also be used to prevent the modem turning off in case a
program send is interrupted and no program is left running in the logger. For
more information on the default.crx file, see your datalogger manual.
11.
Additional Hardware
11.1.1
Power Supply
The Intelimax modem can be powered in a number of ways. The power supply
wires can be connected directly to battery terminals, to the logger 12V or
SW12V supplies or to some external relay circuit. Custom data logger
programs can be used to control power to the modem using SW12 or a relay.
See the data logger manual for details of using the switched 12V supply.
Warning
