Self-Adjusting Telegram-Receiving Slave Clocks
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PEWETA DCFport24 pulse telegram (wire transmitted)
PEWETA AirPort24 RF telegram (wireless)
PEWETA telegram-receiving slave clocks offer an advantage over conventional, “classic” slave clocks by not
being advanced by pulses but being adjusted by time
and date telegrams.
Time adjustment is fully automatic and independent of the current position of the hands. The time
telegram (hour, minute, second, day, month, year) is
transmitted by a PEWETA master clock either by wire
(PEWETA DCFport24) or by a separate UHF transmitter
(PEWETA AirPort24) in the 868 ... 869 MHz frequency
band to the slave clocks. All analog telegram slave clocks
up to 435 mm diameter already are provided with a
central second hand, so the accurate DCF77 or GPS controlled time will be displayed accurately to the second.
Clock control
systems
Technical
information
230 V
Quartz
DCF
DCF
Quartz
min
min
min/sec
min/sec
DCFport
24
DCFport
24
AirPort
24
AirPort
24
24
4
sec
DCFport
24
NTP
client
DCF77
or GPS
230 V AC
50 Hz
Telegram slave clocks will fully automatically reset
themselves to the accurate time after accidental disruptions (wire break, loss of mains power). This is of special
benefit in installing and maintaining clock systems with
large numbers of slave clocks, clocks with two or four
faces or clocks mounted in areas with difficult access,
like in high halls or outdoors. Wire-based PEWETA
DCFport24 clocks are also powered over the telegram
transmitting line. Wireless PEWETA AirPort24 clocks can
be provided for operation on either battery or 230 V AC
mains power.
DCFport24
AirPort24
1,5 V
Advantages
■ Simple, cost-effective “plug-and-play” installation
■ Rapid self-adjustment with no previous manual set-up
■ No need to pay attention to polarity
■ Existing slave clock wire networks may be re-used.
Operating feature
operating mode
Conventional
minute pulse slave clocks
12/24/48/60 V minute pulse
DCFport24
pulse telegram slave clocks
24 V pulse telegram
transmitting wire
2-core wire, shielded
2-core wire, shielded
transmitted signal
polarity alternating minute pulse
complete date-time information
face/dial (up to 435 mm)
hour and minute hands
hour, minute and second hands
face/dial (over 435 mm)
hour and minute hands
hour and minute hands
date display
must be manually pre-set before initiation
date and time will be set automatically
initiation procedure
All slave clocks must be connected with uniform polarity and manually pre-set to the planned initiation time.
All clocks must be initiated simultaneously.
Slave clocks may be installed with random polarity, random position of hands and in any convenient sequence.
Time display adjustment will be fully automatic.
after initiation
Each slave clock must be individually checked for correct polarity of connection. Any discrepancies of hand
position must be manually corrected.
No after-initiation check is required. All clocks have
automatically “slaved” to the master clock time display.
additional clocks/lines
The line involved must be stopped.
All newly installed clocks must be manually set to
match existing clocks.
Additional clocks may be installed and connected in
“plug-and-play” fashion at any time and will automatically adopt the master clock time display.
after line disruptions
The line involved must be stopped.
Clocks lagging behind because of missed pulses must be
manually reset.
Each and every slave clock will automatically reset itself
when the telegram circuit is restored.
The Easy Way to Understand NTP
■ Network Time Protocol (NTP)
is a server-client- protocol used to provide time synchronisation in IT-networks. Local networks (LAN) in
industry or public administration may use it as well
as wide-ranging networks, e. g. the Internet. NTP is
universally compatible. Originally developed for the
UNIX Operating System, today it is synchronising all
relevant Operating Systems, like Windows, Mac OS,
Linux ...
Only in a time-synchronised network it is possible
to correctly document data files at different states
of processing and derive useful information from
protocol entries. Nowadays, an accurate time-base
is absolutely essential in almost all applications and
services.
The PEWETA NTP-time-server (see page 186) offers
you this accurate time-base, which provides time
derived from a high level time standard (DCF77- or
GPS-receiver) or a PEWETA type 920 master clock
to the IT infrastructure. This enables all so-called
»clients« installed in the network, e. g. PCs, telephone systems, printers or clocks to synchronise
themselves with this time-base. PEWETA NTP slave
clocks (NTP clients) may receive the NTP protocol
from a variety of NTP servers (provided by PEWETA
or already installed) and adjust themselves, accurate
to the second. NTP provides UTC time (Universal Time
Co-ordinated). As every PEWETA NTP slave clock may
be adjusted to the local time zone or any other time
zone desired by the user, these clocks may be used
world-wide or may be assembled into a world time
display.
DCF77Receiver
GPSReceiver
GPSReceiver
DCF77Receiver
Master Clock
Router/
NTP-Client
Internet
PEWETA NTP-Server
PEWETA
AirPort24
Transmitter
PC-Client/
NTP-Client
PEWETA
AirPort24
Slave Clocks
LAN
Clock control
systems
Technical
information
PEWETA
NTP-Clock Client
powered by Ethernet
230 V
Quartz
PEWETA
NTP-Slave Clocks
powered by
Ethernet
PEWETA
AirPort24
Repeater
Subordinate
Master Clock
Slave Clocks
PEWETA DCFport24
Slave Clocks
PEWETA
Pulse
Amplifier
PEWETA
DCFport24
Slave Clocks
DCF
DCF
Quartz
min
min
min/sec
min/sec
DCFport
24
DCFport
24
AirPort
24
AirPort
24
24
sec
DCFport
24
NTP
client
PEWETA
NTP-Clock Client
powered by Ethernet
Operating Mode “Classics”
230 V
Quartz
DCF
DCF
min
min/sec
min
sec
Synchronous clocks,
230 V AC/50 Hz
mains operated
Quartz clocks,
battery operated 1.5 V
Operating Mode
Accuracy is dependent on the frequency of the
mains power grid, synchronous clocks are accurate
at exactly 50 Hz. When mains power is lost, clocks
will stop. Setting and changing the time indication
are manual.
Accuracy is determined by an oscillating crystal.
Average deviation is less than 1 second/day. Setting
and changing the time indication are manual.
DCF77 radio controlled clocks, Time indication is synchronised by the time standard
transmitter DCF77 at Mainflingen/Germany and
battery operated 1.5 V
always accurate to the second. Change-over between
summer and winter time is fully automatic.
DCF77 radio controlled clocks, Operation is similar to battery powered DCF77 clocks.
When mains power is lost, clocks will stop, but will
230 V AC/50 Hz operated
immediately re-adjust to correct time when power
is restored.
Slave clocks to be connected to a master clock.
Slave clocks,
Control is by polarity alternating minute pulse. Preminute pulse 12 ... 60 V
setting and changing of time indication are manual.
Slave clocks,
minute/second pulse 12/24 V
Slave clocks,
minute pulse 12/24 V,
synchronous second hand
230 V AC/50 Hz operated
Slave clocks to be connected to a master clock with
at least two output lines. Control is by polarity alternating minute and second pulses. Pre-setting and
changing of time indication are manual.
Slave clocks to be connected to a master clock.
Control is by polarity alternating minute pulse.
Separate synchronous drive for second hand. Presetting and changing of time indication are manual.
Advantages
easy to install
no battery to change
sturdy, long-life movement
second hand included
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independent of mains power
next to no malfunctions
most cost-effective type
second hand included
uniform time indication
adjustment and changeover to summer/
winter time fully automatic
second hand included
uniform time indication
adjustment and changeover to summer/
winter time fully automatic
free of maintenance (no battery to change)
solid, dependable, tried-and-true movement technology
uniform time indication
most cost effective slave clock system
solid, dependable, tried-and-true movement technology
uniform time indication
second hand included
Large, highly visible second hands feasible
for clock faces up to 800 mm diameter (as
known from railway station clocks)
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