Triton Isis - Manual (Page 59)

June 2004 Isis® Sonar User's Manual, Volume 2 49
D.3.4 Template Instructions That Do Not Evaluate to
a Number
Certain letter designators do not correspond to a value transmitted over the
serial interface (and therefore do not evaluate to a number). Instead, these
special letter designators act as signals to Isis that certain instructions are to
occur before parsing the navigation. These designators, shown in Table D-
1, should be placed at the front of the template.
Table D-1. Template letter designators that do not return a number
Letter Meaning
A Forces Isis to synchronize to transmitted time
B Forces Isis to synchronize to transmitted date.
F Tells Isis to interpret northings and eastings as feet.
R Flag which triggers an event closure (sent by MOSNAV) in Isis —
used for verification only.
X Placeholder only; tells Isis to ignore the next value.
Z Benthos SIS-7000 uplink flag: convert depth (m), conductivity, and
pressure from frequency to real values.
P DTDAS flag is set TRUE.
- Tells Isis to reverse the sign of the next value. Use this in front of
longitudes which are transmitted as positive values in the western
hemisphere.
Note: This is not the same as the subtraction operator
for described in ‘Performing Math on Template Tokens’.
! The character that follows '!' is compared to the first character
in the receive string. If they don't match, the string is rejected.
Example: !$ in the template will cause Isis to reject any serial
update that doesn't begin with a dollar-sign ($) character.
$ Informs Isis that northing and easting are actually latitude and
longitude (otherwise, UTM). As a result, Isis will interpret this to be
a NMEA string.
Appendix D: Serial Interfaces