Specifications

3U Traffic Outstation Handbook
667/HB/26568/000 Page 56 Issue 15
5.4.2 Radio Clock Installation
[This section only applies to Bus applications]
The optional Radio Clock is a separate unit that is mounted external to the OMCU
using a bracket supplied with the unit. It provides a time signal to the traffic outstation
received from the MSF Rugby transmitter. This is used to synchronise the internal
real time clock.
The system has good tolerance to interference and only requires valid reception for a
few minutes each day to maintain the accuracy of the clock. It is however a sensitive
radio receiver operating at 60Khz (for Rugby MSF transmissions) and certain
precautions are necessary.
• It should not be located near to radio transmitters.
• It should be kept as far away as practicable from a SIETAG reader or
vehicle detector loops. In some cases detector loops might have to be set
to operate on different channels as they can radiate at the same
frequency as the Rugby transmitter.
• It must be orientated correctly to point towards the Rugby transmitter. See
below and also see ‘RCS’ on page 185 for details on the use of the
handset for verifying radio reception.
Cabling to the Radio Clock should be separate from other intersection cables,
particularly detector loop feeders, to avoid electrical noise being injected into the
Radio Clock via its supply. A screened cable is recommended.
The Radio Clock is required to be connected to a digital input on a Bus / MOVA I/O
Board (defined during the configuration process) and to signal ground. The current
version of the radio clock derives power from its internal battery and no additional
power connection is required. Earlier versions (with 3-core connection cable) require
an external supply, which may be derived from the OMCU via the 13.8V bullet
connector at the rear of the OMCU. If the I/O cable 667/1/26585/010 is used then a
dedicated supply connection is provided.
External Power (7-30V DC)
*
Ground
Time Code Output
Radio Clock Unit
Test Switch
Reception Indication
Internal Connections for
the Radio Clock
Correct Orientation for
the Radio Clock
MSF Rugby Transmitter
Axis of unit at 90
o
from
direction to transmitter
* External power not required on
later models.
Figure 12 – Radio Clock Unit