User manual

User Manual
man_905K_1.10.doc Page 11
2 OPERATION
2.1 Normal Operation
Once configured using the 905K configuration software, the 905K module will normally be in
“sleep” mode to conserve power. During sleep mode, the microprocessor controller powers
down, and the analog loop supply is turned off. The microprocessor will automatically “wake
up” and revert to full operation if a digital/pulse input changes (on to off, or off to on), or every
0.5 seconds to check if a timed update transmission is due to be sent.
Normal operation of the 905K is indicated by a brief flicker of the OK LED light on the front
panel approximately every 10 seconds.
2.2 What information is transmitted over the radio?
The 905K modules transmit the value of the input signal in a data frame. The data frame includes
a system address, and the "address" of the transmitting (or “source”) 905K module and the
receiving (or “destination”) 905U module, so that each transmitted message is acted on only by
the correct receiving unit. The system address is a common address used by all modules in the
same system. This allows multiple systems to operate within the same radio range without
"cross-talk" between systems.
The user configures these addresses as part of the module configuration. Each transmitted
message also includes error checking to ensure that no corruption of the data frame has occurred
due to noise or interference. If repeater modules are being used, then the addresses of these
intermediate modules are also included in the data frame.
The user can configure the 905K to transmit each message from one to five times to ensure that
at least one of the messages is received correctly. Each repeat transmission will occur at random
intervals between 0.5 and 2 seconds.
2.3 How often is the input information sent by radio?
• Change messages. The 905K transmits the value of an input signal whenever the signal
changes.
• Update messages. The input value is also transmitted if the signal has not changed within a
pre-configured update time (configurable 10 seconds to 7 days).
• Paralysis. When a 905K transmits a message for a particular input, the 905K will not
transmit another message for this input within a configured time period. This time is called
the paralysis time, and may be used to prevent a lot of messages being transmitted if an input
changes frequently. The paralysis time may be set from zero to 127.5 seconds for each input.
For example, assume the paralysis time on an input is 30 seconds. If the input changes, then
the 905K will transmit a message, however it will not transmit another message for this input
during the next 30 seconds, regardless of changes to the input signal. Note that paralysis time
does not stop re-transmissions of each message - if the 905K is configured to transmit each