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Jumbo LED Digital Clocks with REMOTE CONTROL
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 programmable sync 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 that all Slaves are supplied from. The Time and Date information  is sent to the slaves and additonal special data or text may also be sent. A PC or other device with RS-232, USB 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. This device or the PC may use GPS, WWVB or Internet as a source of accurate Atomic time data as well.
Special "Repeater" function can extend 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 other device with RS-232, USB or RS-485 serial port may be used as the Master. This device or the PC may use GPS, WWVB or Internet as a source of accurate Atomic time data as well. Special "Repeater" function can extends the range for large systems to prevent the signal degradation.
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 other device with RS-232, USB or RS-485 Serial port may be also used as the Master. This device or the PC may use GPS, WWVB or Internet as a source of accurate time data as well. The RS-485 based system isVERY RELIABLE. and Easily expandable. Fast communication. Up to 400 slaves per Master can be connected without Repeaters within a range of  many miles ( many killometers). A number of standard Time Code protocols may be used since SELENA  clocks are  compatible with most of them and may be  installed in an existing Master Clock systems using the sync signal generated by the existing Master.
Power Line 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 for both 50 nad 60 Hz power lines. 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 the 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.. A PC may be also used as the Master.
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.
APPLICATIONS

HOSPITAL
SCHOOL
AIRPORT
ARMY BASE
MARINE VESSELS
SHIPS, BOATS
SUBMARINES
BANK
STADIUM
GYM
CHURCH
SUBWAY STN.
BUS STN.
RAILWAY STN.
MULTI ZONE Clock System    -   2 WIRES: Low Voltage or wireless
Ask for Multi-zone
Option #725, #724 or  #741
A Multi-Zone clock system can be setup using a number of clocks housed  in separate or in a common enclosure and set to synchronize to different time zones. An external master clock, a PC or one of the clocks in the system may be assigned as the Master for instance with a LOCAL time, ZULU time or any other time reference. It sends the Time synchronizing data to all other  Slaves that are assigned as the Zone Clocks. The system may be synchronized using RS-232, USB or RS-485 serial  wired or wire-less communicaton. This Master or the PC may use GPS, WWVB ( or other stations ) or Internet for sync with the Atomic Clock time as well.
NOTE:  SELENA Multi-Zone system can be setup for Zones that are offset down to 1-Minute resolution, not only the several standard zones.
SELENA clocks add the date, month, year and weekday independently, so that the zone clocks can also display the zone dates and other info. In models with or without the Text display the zones may be setup to alternate with other display modes.
SELENA
LED Clocks
and Timers
Toll Free:  1-866-829-4253
BCD synchronized Clock System  (Simplex compatible )   -   2 WIRES: Low Voltage
Ask for Option #726BCD
A Master - Slave clock system compatible with widely used BCD Simplex time code that has been in use in many schools, hospitals and airports with existing Master clocks. It uses  Serial Communication over a pair of wires ( 2 conductor cable with or without shield ). The Master transmits time data packets synchronized with the local power line so that this system can be used in locations with 50 or 60 Hz power lines. The sync data does not contain the date but the SELENA clocks add the date, month, year and weekday independently so that the slaves are fully synchronized.
GPS Atomic time synchronized Clock System
A Stand Alone or Master - Slave clock system that uses the Atomic time data received by a GPS (Global Positionig Satellite) receiver from the satellites. A small GPS receiver must be exposed to see the sky in order to get the radio signals. The receiver is connected to a stand-alone clock or to one of the clocks assigned as the Sub-Master that transmits the sync to the rest of the slaves in the network. The internal network may be any of the other sync communication types,  wired or wire-less.
Ask for Option #725GPS
All SELENA clocks have this option included.
Atomic Clock time received from WWVB, DCF77, JJY, MSF or HGB Time Radio Transmitters
A Stand Alone or Master - Slave clock system that uses the Atomic time data received from the time radio broadcast transmitters. A special radio receiver may be either a separate device or may be installed inside a stand-alone clock, or in one of the clocks assigned as the Sub-Master that transmits the sync to the rest of the slaves in the Master - Slave network. The internal network may be any of the other sync communication types,  wired or wire-less.
Ask for Option #725WWVB
or #725DCF or #725JJY
or #725MSF or #725HGB
SELENA clocks are compatible with a variety of time sync protocols and standards like ASCII time code, Lathem system, Simplex system, 58th and 59th minute, BCD time code, Minute impulse etc...
However the native SELENA protocol is recommended as it is very fast, secure and flexible.
Custom modified or designed communication protocols and formats are available upon request.