GPSPCI 2/72008 Rev 1.2.1
3
Masterclock, Inc.
During such outages the GPSPCI will continue to generate time information referenced to the
last available satellite timing information. This mode is referred to as freewheeling. When the
unit first acquires satellite time, it calibrates an internal clock against the incoming atomic time.
During freewheeling the time information will be referenced to this clock and will typically be
accurate to within a few milliseconds over a 24 hour period (if the power is not disconnected).
As is covered in other areas of this instruction book, the freewheeling status is encoded/decoded
by the McrSync software supplied by Masterclock and the operator is given the option of
synchronizing to the time information during the freewheeling state.
The transition to and from freewheeling mode is seamless - it does not interrupt time information
output.
FREEWHEELING/NON LOCKED LED INDICATION
During a freewheeling period the card LED will be off.
HARDWARE – OPERATING ENVIRONMENT
The GPSPCI is not water or moisture proof. Treat it as you would any other delicate electronic
device and do not expose it to water, excessive heat or physical abuse.
SAMPLE WINDOWS APPLICATIONS & BUS PROTOCOL
Included with the GPSPCI (MCRPCI) drivers for Windows, are sample Windows GUI
applications and source code in Visual Basic and Visual C++. These items are provided as-is to
our end users or to developers. Upon running the MCRSETUP.EXE file that is included with
the drivers is run, the sample application and source code is located in the C:\Program
Files\Masterclock\MCR directory.
A screen shot of the Visual Basic GUI application is shown below.
