Westermo RM-505U-K - Manual (Page 8)

505K Radio Telemetry Module User Manual
    ELPRO Technologies Pty Ltd 2008 Page 8
2 OPERATION
2.1 Normal Operation
Once configured using the 505K configuration software, the 505K module will normally be in
“sleep” mode to conserve power. During sleep mode, the microprocessor controller powers
down, and the analogue 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 505K 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 505K 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”) 505K module
and the receiving (or “destination”) 105U 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 505K 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 ??one and four seconds.
2.3 How often is the input information sent by radio?
• Change messages. The 505K 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 505K transmits a message for a particular input, the 505K 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 505K 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
505K is configured to transmit each message three times, then paralysis will not stop this.
Depending on the type of input signal (digital, pulse or analogue), the 505K must determine
what type of signal change is required to send a transmission: