Clock network

A watch or timer service facility is a facility that provides for equal time displays at various locations.

Use

Clock systems are often installed in larger establishments or public buildings such as schools, hospitals, railway stations or airports. Specifically, the German railways have long huge synchronized networks operated in which the station clocks had only minor deviations.

Components

A clock system is next to the power supply always from the master clock or master clock and slave clocks controlled by it or daughter watches. From a slave clock to nationally -driven clock systems all intermediate stages are possible. A clock system can be provided with additional signaling devices. Signal receiver of such systems can be piercing and punch clocks, Frankieranlagen, validators or a Speaking Clock. Most are also switching outputs for the control of operations to be triggered at certain times, such as a break gongs available.

When timer can mutually get in synchronism optionally two or more master clocks. It is also possible to remote control electro-mechanical master clocks from a parent time signal source. In case of power failure, a follow-up device stores the information about the number of non- transmitted to the slave clock pulses to recreate them automatically when back existing voltage. In a follow-up device can be dispensed with in particular battery powered or equipped with emergency power supply systems.

Slave clocks

The slave clocks usually involve only a Lavet stepper motor, which is further provided by the signal pulses of the master clock. The show connected to the same master clock slave clocks, at least as long as the net no technical problems arise, always all the same time. Also, corrections, such as the summer or winter time, are central and thus easily feasible. The maintenance of the system is significantly cheaper than at a large number of independent individual watches.

Another method is free-running, operated with a synchronous motor from the mains voltage secondary clocks that are minutely synchronized eg with the master clock by the continuously running second hand ( Creeping second) up to the defined release by a pulse of the clock in 12 - clock - position stops. For this purpose, the pointer must run a little faster than the real time during the period between the release pulses. The advantage of this is that the drive power of the clock does not need to be transmitted via the control line.

History

In Germany, the first clock systems end of the 19th century were used, after the German Empire had introduced the Central European Time at the insistence of the railway companies in 1893. Previously on the timetables of trains had to be considered more than 60 local time structures of individual regions and cities. Therefore, the railway is considered the initiator of a unification of the timing in Germany.

After the Second World War, the German Federal Railroad built a network to its network node was one master clock with connections to other master clocks. Every midnight, the nationwide Zeitangleich was carried out by the central clock of the German Hydrographic Institute in Hamburg. According to Deutsche Bahn is currently used as primary clocks 2,500 of its 17,000 watches. They are run and receive the signal from the DCF77 time signal transmitter of a radio watches.

With the widespread use of cheap radio controlled watches the clock systems are in decline. Particularly large systems, such as the webs are divided into small local cells, in which the timing signals not coming from a central clock; they are synchronized via the transmitter DCF77 of the Physikalisch- Technische Bundesanstalt in Braunschweig, or over comparable time services of other countries (BEV Vienna, HBG transmitter Neuchâtel, OMA Prague). Frequently, radio-controlled watches single apply. Since in many buildings, however no DCF77 signal can be received, the clock systems will be replaced in the future by not fully radio controlled watches.

Major manufacturers

The watchmaker and businessman Carl Theodor Wagner owned a patent for the operation of slave clocks. His company also produced for Siemens & Halske (later Siemens AG) and Standard Elektrik Lorenz (SEL ), which also distributed clock systems and manufactured. Another big name in watches plant is Telefonbau and Standard Time (T & N or tele Norma now Bosch Security Systems ). In the DDR clock systems under the trademark fair RFT or Elfema (electrical mechanics Mittweida ) were expelled. All of these companies no longer exist or no longer build time systems.

The company Bürk delivered until well into the 1990s, for example, watches for the German railway. Today it is a part of the Swiss Mobatime. In the Czech Republic ELEKTROČAS produced (successor of Pragotron ) clock systems. Two major manufacturers of clock systems remained in Germany: The medium-sized enterprises JUNDES imperial period Metrology (formerly Jauch and Schmid), which manufactures specialty watches since the beginning of the 20th century, and by Robert Bosch GmbH.