Getting Started 23
Getting Started
describes how to send commands to and receive information from the G12 using
an IBM-compatible PC. You can interface with the G12 using Evaluate
Software™, RCS (Receiver Communication Software™), or standard
communication programs such a ProComm or Hyperterminal. To begin, simply
connect the standard 9-pin serial cable supplied in the G12 evaluation kits
between port A on the G12 and COM1 on the computer.
After setting up the interface for establishing communications with the G12, you
are now ready to send commands. The letters in your command can be typed in
UPPER or LOWER case and completed by pressing <Enter>. If you sent the
command correctly, you should get a response.
The commands used with the G12 are divided into two groups: Set commands
allow you to change the G12’s operating parameters and begin with the command
string $PASHS. Query commands allow you request information from the G12,
such as the current operating parameters, current position, or DGPS status. Query
commands begin with the command string $PASHQ. The G12 responds to query
and set commands by issuing an acknowledgement of a change in operating
parameters or with the specific information requested through a query.
To become familiar with the G12 messages, send a few common commands to
the G12 and observe the responses. In the following steps, command messages
appear as COMMAND, and response messages appear as RESPONSE.
1. Type: $PASHQ,PRT and press <Enter>. This command queries the
communication setup of the port. If interfacing through serial port A, the
response message is:
$PASHR,PRT,A,5
This message indicates Port A of the G12 is using its default communications
setup 5: 9600 baud, eight data bits, no parity, and one stop bit.
2. Type $PASHQ,STA and press <Enter>. This command queries which
satellites are locked and their signal strength at the time the command is
sent.The response message typically might display:
TIME: 18:38:31 UTC
LOCKED:03 23 16
COUNT :54 26 17
3. If interfacing through port A, type $PASHS,NME,POS,A,ON,1 and press
<Enter>. This commands the G12 to return comprehensive position
information through port A at a set rate. The default rate for NME commands
is once per second. The response message output rate is 1 HZ:
$PASHR,POS,0,08,164152.90,3721.06962,N,12156.12176,W,+00003.16,
,008.64,000.55,+000.03,01.7,01.0,01.4,00.9,GH00*20
The data string contains the position information, assuming the receiver is
tracking a sufficient number of SVs to compute a position.
G12RevD.book Page 23 Tuesday, April 2, 2002 4:33 PM
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