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Page 4 3 GPS170SV Features
3.3 Time Capture Inputs
Two time capture inputs called User Capture 0 and 1 are provided at the rear connector (CAP0 and CAP1) to
measure asynchronous time events. A falling TTL slope at one of these inputs lets the microprocessor save the
current real time in its capture buer. From the buer, capture events are transmitted via COM0 or COM1 and
displayed on LCD. The capture buer can hold more than 500 events, so either a burst of events with intervals
down to less than 1.5 msec can be recorded or a continuous stream of events at a lower rate depending on the
transmission speed of COM0 or COM1 can be measured.
The format of the output string is ASCII, see the technical specications at the end of this document for details.
If the capture buer is full a message "** capture buer full" is transmitted, if the interval between two captures
is too short the warning "** capture overrun" is being sent.
3.4 Asynchronous Serial Ports (optional 4x COM)
Four asynchronous serial RS232 interfaces (COM0 ... COM3) are available to the user. In the default mode
of operation, the serial outputs are disabled until the receiver has synchronized after power-up. However, the
system can be congured to enable those outputs immediately after power-up. Transmission speeds, framings
and mode of operation can be congured separately using the setup menu. COM0 is compatible with other radio
remote clocks made by Meinberg. It sends the time string either once per second, once per minute or on request
with ASCII ? only. Also the interfaces can be congured to transmit capture data either automatically when
available or on request. The format of the output strings is ASCII, see the technical specications at the end
of this document for details. A separate document with programming instructions can be requested dening a
binary data format which can be used to exchange parameters with GPS170 via COM0.
3.5 DCF77 Emulation
The satellite controlled clock generates TTL level time marks (active HIGH) which are compatible with the time
marks spread by the German long wave transmitter DCF77. This long wave transmitter installed in Mainingen
near Frankfurt/Germany transmits the reference time of the Federal Republic of Germany: time of day, date
of month and day of week in BCD coded second pulses. Once every minute the complete time information is
transmitted. However, the generates time marks representing its local time as congured by the user, including
announcement of changes in daylight saving and announcement of leap seconds. The coding sheme is given
below:
M Start of Minute (0.1 s)
R RF Transmission via secondary antenna
A1 Announcement of a change in daylight saving
Z1, Z2 Time zone identification
Z1, Z2 = 0, 1: Daylight saving disabled
Z1, Z2 = 1, 0: Daylight saving enabled
A2 Announcement of a leap second
S Start of time code information
P1, P2, P3 Even parity bits
0
10
20
30
40
50
R
M
1
4
2
1
20
10
8
4
2
1
P
2
0
2
0
1
8
4
2
1
2
4
8
10
1
2
4
8
10
2
0
4
0
8
0
3
P
A1
Z1
Z2
A2
S
1
2
4
8
1
0 2
0
4
0
1
P Minute
(reserved)
Hour
Day of Month
Day of Week
Year of the Century
Month of Year
Time marks start at the beginning of new second. If a binary "0" is to be transmitted, the length of the
corresponding time mark is 100 msec, if a binary "1" is transmitted, the time mark has a length of 200 msec.
The information on the current date and time as well as some parity and status bits can be decoded from the
time marks of the 15th up to the 58th second every minute. The absence of any time mark at the 59th second
of a minute signals that a new minute will begin with the next time mark. The DCF emulation output is enabled
immediately after power-up.
4 Date: 4th November 2013 GPS170SV