S
YSTEM
P
ARAMETERIZATION AND
O
PERATION
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6842 GPS Slim Line System - V09.01
hopf
Elektronik GmbH
Nottebohmstr. 41 • D-58511 Lüdenscheid • Tel.: +49 (0)2351 9386-86 • Fax: +49 (0)2351 9386-93 • Internet: http://www.hopf.com • E-Mail: [email protected]
Delays cannot be added for system status change and DCF77 simulation.
Sample setting: System status change
10
min. / DCF77 simulation
3
min.
DCF77 simulation changes to 2 Hz modulation after 3 minutes reception
failure, not after 13 minutes.
DCF77 Sim.-Signal Accuracy Calculation Example
The time delay to be set depends on the required accuracy of the connected sub-system.
The accuracy of the internal quartz base is assumed to be
±
1*10E-6 in this example. The
minimum accuracy required is
5msec.
0.005s / (1 x 10E-6) = 5000s =
83 minutes 20 seconds
Ö
The
maximum
value to be set for
'DCF-SIM STOP AFTER'
is
83 minutes
.
4.1.4.3 DCF77 Pulse Width
The time information is transmitted in BCD format in the DCF77 time telegram. In this case
logic 1
corresponds to a pulse length of 200msec. and logic 0
to 100msec. (see
Chapter
11.2 DCF77 (German Long-Wave Transmitter Frankfurt 77.5kHz)
).
Some manufacturers do not adhere to this definition and transmit shortened pulses, for
example 160msec.
for Logic 1 and 70msec. for Logic 0.
The pulse width is adjustable in
order to be able to synchronize this equipment as well.
For the "
true
" DCF77 signal the pulse widths are defined as follows:
•
LOW pulse = 100msec. (Logic 0)
•
HIGH pulse = 200msec. (Logic 1)
For the synchronisation of
hopf
devices only these pulse widths are used.
Displaying and Changing the DCF77 HIGH Pulse
Viewing and changing the pulse takes place on the same display frame and is called up as
follows:
Selection frame:
S E T D C F
H I G H - P U L S Y / N _
Display frame:
D C F - H I G H - P U L S
>
2 0 0
< M S E C _
STANDARD Value: 200
The currently valid DCF77 pulse width is shown.
The time is increased with the
+
key and reduced with
-
.
On exiting the program via the
BREAK
key the last displayed value is stored in a failsafe
manner.
