17
Operation
The DuraTime master clock obtains time updates from local or public time servers, and/or from
the optional GPS receiver. The time received is used to update the master clock’s internal
temperature compensated quartz oscillator. The internal clock is backed up using a 10 year
Lithium battery to prevent time disruptions due to power outages. All master clock
configuration parameters are stored in non-volatile memory and are unaffected by power
outages. Any number of master clocks may be used for improved system reliability.
The master clock transmits time updates using a 2.4 GHz Direct Sequence, Spread Spectrum
digital radio. All data transmitted is encrypted using AES-128 bit data encryption for security
and reliability. The RC100 master clock broadcasts time updates every other second (43,200
times per day).
Adjusting the time
The clock is factory synchronized with the atomic clock and normally does not require further
adjustment. If adjustment is required, then it is recommended that NTP or GPS be used to set the
time. The master clock can be manually adjusted with the Up and Down buttons. These buttons
are normally disabled. Press both buttons at the same time to enable. When the Up or Down
buttons are pressed, the minute will change and the seconds will reset to zero. To set the clock to
the exact second, use known accurate time reference. Change the master clock at exactly the top
of the minute.
Above is a dual-redundant master clock configuration with control buttons and LED displays. The primary master
clock is on top as indicated by the “P” on the display. It is actively broadcasting time packets as indicated by a “T”.
The secondary master clock as indicated by the “S” on the display is in standby mode as indicated by the absence of
a “T”. The secondary master clock will automatically begin transmitting if the primary fails to transmit time packets
or loses GPS or NTP sync. Both clocks are in sync with the atomic clock as indicated by the “H” character,
indicating the internal high precision oscillator is being used. Other valid sync indicators are “G” for GPS and “E”
for Ethernet NTP. Transmissions to wireless alarm devices will only be sent if there is a “T” displayed. The
absence of a “P” or “S” indicates the master clock is configured for single master clock operation. It will always
transmit in this configuration, regardless of the presence of other master clocks or sync reception.
When dual redundant master clocks are utilized, the secondary master clock will automatically
begin broadcasting time if the primary master clock loses GPS or NTP sync, or stop sending time
packets. When the primary master clock problem is corrected, it will resume broadcasting time
and the secondary master clock will cease sending time. Both master clocks will receive and use
time GPS or NTP time updates whether they are broadcasting time or not. A “T” on the display
indicates that it is actively broadcasting time packets. For more information about configuring
dual redundant master clocks, see Mode 32-69 in the Master Clock Configuration Menu section
of this manual. In dual-redundant master clock configurations, a “P” on the right side of the
display indicates that it’s configured as a primary master clock. An “S” indicates it’s configured
as a secondary master clock. The absence of a “P” or “S” indicates the master clock is
