User's Manual Part 2

March 29, 2006 Part ######A revision 00a-DRAFT 105

Chapter 6: On-Site Configuration procedures

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To configure the GPS clock module

1 Connect a laptop to the GPS clock, as shown in Figure 6.1.

NOTE: The control cable is the cable that connects the GPS clock module to the

GPS CNTL port on the alarm card.

2 Start a serial terminal session using the settings shown in Table 6.3.

NOTE: Depending on your communications software, you may need to append a

linefeed to each issued command (in addition to the pressing Enter). In Minicom on

Linux, use Control+J. For example:

$SSTA* <ENTER> <CTRL-J>

3 Set the compensation for the antenna cable delay:

i Calculate the cable delay by multiplying the total cable length by the delay value. For example, if the

delay value of the cable is 4.36 ns/m and there is 15 m of cable, then the cable delay would be 15 m

x 4.36 ns/m = 65.4 ns. Round the result to the nearest nanosecond. In this case, the result would be

65 ns.

ii Set the cable delay for the first GPS plug-in module. This example uses a cable delay of 65 ns.

Replace the 65 in the following command with your own calculated cable delay value:

$ANT1,65*

↵

iii Set the cable delay for the second GPS plug-in module. Again, replace the 65 in the following

command with your own calculated cable delay value:

$ANT2,65*

↵

The GPS clock module briefly enters coasting mode as it recalculates its position.

4 Set the automatic determination of antenna position for each module:

$PMD1,S*

↵

$PMD2,S*

↵

The GPS clock module enters Survey module and recalculates its position.

5 Configure the GPS output to be expressed in UTC time:

$TIMM,1*

↵

$TIMM,2*

↵

The GPS clock module is now configured.

Parameter Setting

Baud 9600 bits/s

Data bits 8

Parity None

Stop bits 1

Flow control None

ASCII setup Send linefeeds, local character echo on

Table 6.3

GPS Clock Module Serial Port Settings