Leica Geosystems GPS System 500 - Technical Reference Manual - Manual (Page 256)

256 9. The CONFIG Key Technical Reference Manual-4.0.0en
9.17 Interfaces - Event Input
The Event Input interface enables
you to configure the Event Input ports
and parameters. This function is
available only if the necessary
hardware exists.
The Event Input port allows direct
connection to an external device (e.g.
aerial camera). When this device
operates (e.g. the shutter opens), the
time that the event occurred will be
recorded in the GPS
measurements. These records can
later be superimposed on the pro-
cessed kinematic data and the
positions where the events took place
can be interpolated in SKI-Pro.
In adition to the time stamps, the user
can also log positions, velocity and
quality. Events logged during real time
operations can also be exported to an
ASCII file using an appropriate
Format File and the Sensor Transfer
functionality. Refer to Chapter 13 for
further details.
The Limit Error is the time limit
within which PPS shall be generated.
If the time accuracy exceed this value
no PPS output is generated. Change
Limit Error to YES and enter a value
in nanoseconds.
The following technical details provide
pulse characteristics and cable
connectivity.
The time pulse has a 3.3V peak
(= High) on a 50 ohm resistance. The
pulse length is 25 usec with the
leading edge coinciding with the
beginning of each epoch.
The cable should be matched with an
appropriate resistance of 50 ohm.
The connector Type is: Huber &
Suhner FFA.0S.CTAC32Z.
Select Event Input and press EDIT
(F3).
Select Port 1 or 2 or if you want to
use both at the same time 1 & 2.
Select the Polarity according to the
external device you are using. The
polarity selected effects both ports in
the same way.