Specifications

Model E8 Series Operation Manual
E8 Series A5 Manual 9 October 2008
Page 6 of 12
Interface and programming
The unit has one RS232 compatible interface. This is shared between the GPS receiver and the
microcontroller that locks the 10MHz output to the GPS signal. On Initial switch on the interface is
connected to the microcontroller. If no valid interface code is received within 30 seconds, the
interface switches over to the GPS receiver. If a valid interface code is received, the interface
remains connected to the microcontroller until the next power on reset.
GPS interface
The GPS receiver interface uses Motorola binary format. In order to use this, a freeware program
such as WinOncore should be installed on the user’s PC.
Connect the unit to the PC and start the program. It may be necessary to set the port and baud rate
(9600). The receiver is preset to output 3 sentences on a continuous basis. These are Ha,
(position/status/data), Hn, (12 channel TRAIM status message) and Bb (Visible satellites).
The various windows available from the program should show current satellite data, etc.
It is important to note that some parameters shown by the program will not correctly indicate the
actual state of the receiver. This is because the program does not automatically update its
information when started. In particular, the TRAIM algorithm will be shown as off when in fact it is
by default on in the receiver.
For the receiver to operate correctly, the site survey must be enabled, and the TRAIM must be on. If
this is not the case, the receiver will track satellites and compute a fix, but the red lock LED will not
go out, showing the 10MHz output is in the standby state.
If the receiver gets stuck in a state where it does not lock, the user may inadvertently disabled the
TRAIM or the site survey. To get back to a known state, the following should be performed:
The messages can be sent using the message window in the WinOncore software.
Return to factory default state:
"@@Cf"
Enable Position Auto-survey; consult the CW12 user manual for further details
"@@Gd03"
Enable T-RAIM algorithm; consult the CW12 user manual for further details.
- "@@Ge01"
Set the alarm threshold for the T-RAIM algorithm (300ns). See the CW12 user manual for further
details
"@@Gf300"
Request channel T-RAIM status message (sent every second)
"@@Hn01"
If required, the position/status/data message may be turned on:
"@@Ha01"
If required, the visible satellites message may be switched on:
"@@Bb01"
The GPS receiver stores the current status in non volatile memory when switched off.