User manual
905U Wireless I/O Module User Manual
105S Serial I/O Module
Page 24 © October 2001
Chapter Three OPERATION
3.1 Power-up and Normal Operation
When power is initially connected to the module, the module will perform internal diagnostics to check
its functions. The following table details the status of the indicating LED’s on the front panel under
normal operating conditions.
LED Indicator Condition Meaning
OK On Normal Operation
RX Occasional flash Radio Receiving, or
Activity on serial ports
RX Flashes continuously Configuration Mode
RX On Button press when entering
Configuration Mode
TX
(only on 905U units)
Occasional flash Radio Transmitting
PWR On Supply voltage available
from Solar Panel or
SUP1/SUP2
OK Flashes every 5 seconds +24V Supply
overloaded
Additional LED’s provide indication of the status of digital inputs and outputs. LED’s display the status of
each digital input (lit for active), and LED’s display the status of each digital output (lit for active). Other
conditions indicating a fault are described in Chapter Six Troubleshooting.
The module monitors the power supply and provides status of supply failure and battery low voltage for
"mapping" to one of the module's own outputs or transmitting to a remote output. When the module is
powered from a normal supply (i.e. via either of the “SUP” terminals), the PWR LED indicator is lit.
When the modules is powered from a solar panel and battery, the PWR LED indicator is lit only when
the charge current is available (i.e. when the solar panel is receiving light).
If a backup battery is connected, the module will generate a low battery voltage status when the voltage
has dropped to 11.3V for approx 45 seconds. This status may be transmitted to another module. In the
event of excessively low battery voltage (10.8V), the OK LED will go off, the unit will automatically
set all outputs off, and disable the +24V analog loop supply. the OK LED will turn on again after the
battery voltage exceeds 11.8V. This enables installations to be configured so that the battery current
drain is minimised in the event of extended mains failure, reducing the possibility of deep discharge of
batteries.