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LED Clocks
Jumbo LED Digital Clocks with REMOTE CONTROL
SELENA
Master - Slave Synchronized Clock systems supported by SELENA clocks.
A special low frequency signal is injected by the Master into the power line wiring that all Slaves are supplied from. That signal is detected by the Slaves that synchronize themselves automatically at specific time of the day or hours. 12 or 24 hour plus one per hour (58th or 59th  minute) sync signals used.
SELENA clocks have WIDE RANGE of synch frequencies available for DIRECT replacement of old clocks in Existing Power Line Carrier systems.
Ask for Option #724
The Master sends serial data into the power line wiring for all Slaves. Complete Time and Date data is sent to the slaves and additonal special data or text may also be sent. A PC or any device with RS-232 or RS-485 Serial port may be used as the Master. The Master Driver Software is small and works in the background, so this PC can still be used for all other tasks.
Special "Repeater" function extends the range for large systems to prevent the signal degradation.
Power Line Carrier Sync        - NO additional WIRES
Power Line Communication Sync  - NO additional WIRES
Radio Communication Sync        - WIRELESS
Free Band Radio Transmitters and Receivers are used by the Master to transmitt the Time and Date data to the  Slaves. Special data or text may also be sent. A PC or any device with RS-232 or RS-485 Serial port may be used as a Master. Special "Repeater" function extends the range for large systems to prevent the signal degradation.
Ask for Option #725RF
Twisted Pair Wired Communication Sync  -  RS-485 & RS-232 -   2 WIRES
Serial Communication over a pair of wires ( 2 conductor cable with or without shield ). Any one of the clocks or a special Master-Clock can be designated as the Master. It sends the Time and Date data to the  Slaves. Special data or text may also be sent. A PC or any device with RS-232 or RS-485 Serial port may be used as the Master as well.
RS-485 based system isVERY RELIABLE. and Easily expandable. Fast communication. Up to 400 slaves per Master can be connected without Repeaters. Range up to many miles ( many killometers).
A number of standard Time Code protocols may be used. SELENA  is compatible with most of them and may be also  installed in an existing Master Clock systems to use the synch signal generated by the existing Master.
Power Frequency Synchronized system      -  NO WIRING
Based on the Frequency of the AC Supply Power Line 50 or 60 Hz. SELENA clocks recognize the correct frequency automatically. In most areas of the world it is EXTREMELY ACCURATE. Average error usually will not exceed a Few Seconds per Year.
VERY RELIABLE system.  NO WIRING OR SPECIAL EQUIPMENT NEEDED. UNLIMITED NUMBER OF CLOCKS.
ALL SELENA CLOCKS HAVE THIS OPTION as STANDARD.
HIGH or LOW Voltage Impulse Synchronized system      -  2 WIRES: High or Low Voltage
A special High or Low Voltage AC or DC signal impulses are generated by the Master on a dedicated pair of wires. Similar to Power Line Carrier signals but without frequency. SELENA Slaves have optocoupler interface to accept that as a synchronizing impulse. 12 or 24 hour plus one per hour (58th or 59th minute) sync pulses used.
Ask for Option #724HW
or #724LW
2 or 3 Wire, 1-Minute or 1/2-Minute Impulse Sync      -  2 or 3 WIRES: High or Low Voltage
Ask for Option #726B
An older system. 1-minute or 1/2-minute same or reversed polarity impulses are generated by the Master on dedicated 2 or 3 wires. SELENA Slaves have optocoupler interface to accept that as synchronizing impulses. This sytem has uses only in upgrading of older installations, where a number of old electromechanical clocks exists and have to be gradually updated to new standards.
KERA Technologies Inc.
Tel: 905-629-9420   Fax: 905-629-9475
APPLICATIONS

HOSPITAL
AIRPORT
ARMY BASE
BANK
STADIUM
SCHOOL
GYM
CHURCH
SUBWAY STN.
BUS STN.
RAILWAY STN.
Tel: 905-629-9420
Fax: 905-629-9475
Toll Free:  1-866-829-4253 
MULTI ZONE Clock System    -   2 WIRES: Low Voltage
Ask for Option #741
A Multi-Zone clock system can be setup using Serial Communication over a pair of wires ( 2 conductor cable with or without shield ). One of the clocks in the system is assigned as the Master for instance with a LOCAL time or a ZULU time. It sends the Time synchronizing data to all other  Slaves that are assigned as the Zone Clocks.  In addition, if combined with another Synch option ( like option # 725 ) the Master clock may be synchronized to the reference time ( for instance ZULU or Loacal ) from a PC or any other Master device with RS-232 or RS-485 Serial port.
NOTE:  SELENA Multi-Zone system can be setup for Zones that are offset down to 1-Minute resolution, not only the several standard zones.