Churchill Nano Link IP67, Technical Manual, Page: 10 / 42

Page 8
3.3.2 Universal Mains Power Supply
An internal mains power pack can be fitted, which derives a 5.3V supply from any input in the range 80…260VAC.
The supply includes rechargeable Ni-Cad batteries, which will support the unit in the event of a mains power failure.
Nano_Link
monitors the battery voltage as an analogue value that can be read by the base-station, and generates a
digital alarm if it drops below a defined level. If a mains fail indication is required a mains-operated relay can be used
externally, with its contacts connected to one of
Nano_Link
’s digital inputs. The period for which the batteries will
support
Nano_Link
depends on the mode of operation, but will typically be at least 8 hours.
The power supply is double insulated, so does not require a safety earth. The power input is through a two-part screw
connector that is different both in size and colour from all other terminals, to ensure it cannot be incorrectly fitted.
Mains power should be used for any
Nano_Link
used as a base-station, a repeater or an outstation that is interrogated
continuously, used analogue or digital outputs or is fitted with expansion modules. It can also be used for an outstation
that is interrogated relatively infrequently.
3.3.3 External 12/24VDC Source
Two variants of this supply are available, one operating from a supply in the range 8…16VDC and the other for
16…32VDC. They are intended for operation from station supplies of nominally 12V and 24V respectively. If the
user wishes to monitor the battery voltage, and/or generate a battery low alarm, the 7041 Solar Power Controller
described below can be used by connecting the station battery to it and omitting the solar panel.
3.3.4 Solar Supply
Solar power requires an external solar panel, a solar controller and a lead-acid battery. The battery is required to
maintain the system overnight and during bad weather. Its size has to be calculated, along with that of the solar panel,
to ensure that the system continues operation throughout the year. Factors influencing the size of the panel and battery
include the electrical load, the location and the ambient temperature range. The controller ensures that the battery is not
overcharged during bright sunlight, and does not discharge into the panel at night.
Nano_Link
‘s supplied for solar operation are fitted with an internal 12VDC power supply, and use an external 7041
Solar Power Controller and battery. The controller is fitted in a small housing that clips onto DIN rail adjacent to
Nano_Link
. The battery is normally fitted at the bottom of the enclosure. An important feature of the 7041 Solar
Power Controller is its very low internal power dissipation. Some commercially-available solar controllers are
designed for us with large solar panels and batteries, and consume more current than
Nano_Link
! They therefore
significantly reduce battery life when used on small systems.
As well as controlling charge to the battery, the 7041 Solar Power Controller also provides a digital Battery Low Alarm
output that can be connected directly to one of the digital inputs on
Nano_Link
. There is also a voltage monitor which
provides a level of 0…100mV for a battery voltage range of 0…20V. This output can be connected to one of the
analogue inputs on
Nano_Link
if required.
The 7041 Solar Power Controller has two LEDs, marked ‘Charging’ and ‘Charged’. The Charging LED flashes when
the battery is being charged by the solar panel. If the battery attains a fully-charged state the ‘Charged’ LED lights, and
the controller shorts out the solar panel to prevent further charging. In the quiescent state both LEDs will flash
alternately as a trickle charge is fed to the battery to maintain equilibrium.
Whenever the solar panel is not charging the battery (e.g. at night) the Charged LED will flash and the Charging LED
will remain off. If the battery voltage drops below 11V the flash rate will slow to about 1 pulse/second and the Battery
Low Alarm will be generated.