Meinberg FUNKUHREN ANZ14_V3, Руководство по эксплуатации

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Features of the AM Radio Clock DCF77 ANZ14 V3
The ANZ14 V3 is a stand-alone radio clock with integrated DCF77 receiver and
power supply. The 14-digit LED display shows time, date and day-of-week. The
displays brightness is variable in four levels. A time string is sent via the serial port
either periodic once per second/minute or only on request by sending an ASCII '
?
'.
The format of the time string is described in the section "Technical Specifications".
The serial port can be set up either as RS232 port or as 20mA current loop port.
Baudrate, framing and time zone can be configured separately by DIL switches. It is
also possible to use the ANZ14 V3 as a display for a preconnected clock. In this case
the partially equipped version without DCF77 receiver is sufficient.
Front View ANZ14 V3
LF Receiver
An external ferrit antenna is used to receive the signal from DCF77 and supplies it to
the on-board LF receiver where it is demodulated by a straight detector with automatic
gain control. The demodulated time marks are fed to the clock´s microprocessor.
Microprocessor System
The time marks from the receiver circuit are filtered and decoded by the microproces-
sor system. Parity and consistency checks over a period of two minutes take care for
detecting errors in the received time telegram. The checked and decoded time is
written to the on-board real time clock and spread by the interface. A software
watchdog lets the microprocessor recover from malfunction. A power-fail comparator
resets the microprocessor if the supply voltage drops below a specified threshold.
Aflash EPROM located in the microprocessor is used as program memory that can be
loaded with the firmware by the serial interface.