Specifications
3U Traffic Outstation Handbook
667/HB/26568/000 Page 186 Issue 15
The OMCU internal clock is only synchronised to the radio clock time signal when
the radio clock signal has been received correctly over two consecutive minutes and
the RF quality indicated by the radio clock is good.
After power on, the radio clock takes 10 to 15 minutes to indicate good RF quality to
the OMCU. During this period, the RFQ error count is incremented. The error counts
are cleared when the OMCU synchronises to the radio clock signal.
In times of poor radio propagation it may not be possible for the clock unit to
synchronise the OMCU. However good reception is only required for a few minutes
each day to maintain the accuracy of the OMCU’s real time clock.
As an additional installation aid a signal reception indicator is present in the Radio
Clock unit. When the ‘test switch’ within the Radio Clock is pressed the Reception
Indication LED will flash regularly for about 1 minute if good signal strength is
present. If random flashes are displayed then the reception is poor and the clock unit
may not be correctly orientated.
11.9 BUS OPERATING COMMAND TABLE
Code
Major
Index
Minor
Index
Data
Range Description
Access
Level
DBM
- - -
Display Bus Messages: Real time
monitoring of bus/vehicle detection
message reception on all RS485
channels.
RO
OLG
- - -
Operations Log: Display time
stamped operations log, one line at
a time. Shows the date and time of
the most recent vehicle detections.
See overleaf for description.
<space key> moves to end of log
+ key shows earlier entry
- key shows later entry
RO
BRX
(Issue
13 or
later)
- - -
Bus Receive message simulation:
The character string entered is
treated as if it had just been
received on the first RS485 serial
channel. Character strings
beginning 0 - 9 or A - F have the
TCSU ‘framing’ (STX, checksum
and ETX) added automatically,
unless the 2
nd
character is an ‘L’.
In this case the string is treated as
a SIETAG detection from a V3.3
(or later) SIETAG reader, by
appending a CR.
Any other strings are just
appended with CR (as used on
Maint