Meinberg GPS162 - Manual (Page 9)

9
Asynchronous serial ports
Two asynchronous serial interfaces (RS-232) called COM0 and COM1 are available
to the user. Transmission speeds, framings and the kind of the time string can be
configured separately. The serial ports are sending a time string either once per
second, once per minute or on request with ASCII ‘?’ only. Possible time strings are
‘Meinberg Standard’, ‘SAT’, ‘UNI Erlangen (NTP)’, ‘Computime’, ‘ABB-SPA’,
‘Racal’ or ‘NMEA (RMC)’, see the technical specifications for details. Furthermore,
the serial interface COM0 is used for communication with the monitor program. A
possible firmware update is also done via this serial channel.
Enabling of outputs
In the default mode of operation the pulse outputs and the serial interfaces are
disabled until the receiver has synchronized after power-up. However, with the help
of GPSMON32 the system can be configured to enable those outputs immediately
after power-up. This option can be set for each group of signals (pulses and serial
interfaces) seperately.
Status outputs
The satellite receiver clock GPS162 provides two TTL-outputs (/FAIL and LOCK)
for handing-over the status of synchronization of timing and calculation of position
to post-connected systems. These outputs can be used for driving LEDs via an
external resistor (R
min
= 470
Ω).
/FAIL output
The ‘/FAIL’ output switches to TTL high level whenever the internal timing of the
receiver is synchronous to the GPS-system.
LOCK output
The ‘LOCK’ output switches to TTL high level if the receiver has acquired at least
four satellites and has computed its position after power-up. In normal operation the
receiver position is updated continuously as long as at least four satellites can be
received. When the receivers position is known and steady only, a single satellite
needs to be received for synchronization and generatation of output pulses.