QTech Data Systems RA2 system - Manual (Page 3)

Wireless Point to Point – RA2 – Quick Start Guide – v1.1 – February 2014 3
www.qtech.co.nz Tel: 03 3663713
The supplied AAA Alkaline batteries should, under normal usage, provide 3 to 6 months
standby operation.
The RA2 standby current is approx. 400µA, the transmit current is approx.. 28mA.
RA2 Battery Selection Notes
The RA2s are battery powered, low power transmitters ideal for short range applications. The
quality and capacity of the batteries used has an impact on the life expectancy and range. As
a minimum always use premium quality alkaline batteries. When selecting batteries, the
usage can be considered the same as a digital camera on the selection charts.
For frequent use applications, we recommend purchasing premium Lithium Ion AAA batteries.
While they are more expensive they have significantly better long term performance and will
need less frequent replacing.
WP2P Module - Power Supply Notes
Power Supply & Current Consumption
The WP2P module operates from a nominal 12 Volt DC power supply.
Current consumption is ~32mA in standby (no output relays active) to 49/66/83mA (one, two
or three relays active).
The WP2P module power connector is a 2.1mm DC Socket, centre pin positive. The supply
voltage should be clean, continuous and transient free with an output of 12 Volts +/- 1.5 Volt
DC. The WP2P incorporates reverse and overvoltage protection.
The absolute maximum supply voltage is 13.8 V DC and any solar/battery design needs to
take this into account.
Warning – Do NOT use Switch Mode Power Supplies (SMPS) with this product. The
DC power supply used for this product MUST have a grounded negative or be a
“linear” transformer based plug pack. The reason is that the aerial, programming port
and external connections can provide exposed earth points and the SMPS can impose
an AC voltage on the DC ground, which can lead to damage. Suitable cost effective
plug packs are available from QTech P/N PD5412, PD5413 & PD5414.
Internal Fuse
The WP2P module circuit is protected by a 20mm x 5mm 500mA fast blow fuse. This is
located on the internal circuit board. To access the fuse, remove the top cover by prizing it off
its retaining dimples. Only replace the fuse with an identical type, do not use alternatives.
This fuse will blow if the power supply maximum voltage is exceeded.
Over Voltage Protection
The WP2P module is over voltage pr
otected by a 13 volt Zener Diode ‘crow bar’ that will
conduct and blow the internal fuse for voltages >14 volts. The WP2P will tolerate 13.8 volts,
but will begin to draw excessive current and blow the fuse at input voltages >14.6V.
Note – Solar Supplies and design considerations
Before using any WP2P module in a solar powered system please check our “Solar
Application Note” on our website. Explicit consideration must be given to the
maximum voltage and voltage regulation to prevent damage.
Installation and Operation Notes
Output Relays
The output relays (Labelled RLY1, RLY2 and RLY3) are normally open contacts that are rated
at maximum of 2Amps. The relays are internally protected by solid state snubbers for
operating with inductive loads.