Measurement Computing LogBook Series - Manual (Page 98)

6-10 GPS and Serial Device Data Collection 958396 LogBook User’s Manual
Channel Type Selection Table
The following table shows the required channel type selection for each valid conversion type specifier. This
table does not apply to format directives using the reject indicator ("*"). The Sx in the table represents serial
ports S1 or S2.
Conversion Type
Specifier
Description Required
Channel Type
Value Range
c character Sx_Char –128 to 127
d signed decimal integer Sx_Int –32,768 to 32,767
e scientific notation floating point Sx_Float 3.4E +/- 38 (7 digits)
f non-scientific notation floating point Sx_Float 3.4E +/- 38 (7 digits)
g either e or f formats Sx_Float 3.4E +/- 38 (7 digits)
i optional signed octal, hexadecimal, or decimal
integer Sx_Int –32,768 to 32,767
o octal integer Sx_Int –32,768 to 32,767
s string (reject only) N/A N/A
u unsigned decimal integer Sx_Int 0 to 65535
x hexadecimal integer Sx_Int –32,768 to 32,767
% N/A N/A N/A
GPS Examples
The following block of characters is an example of typical GPS receiver data:
$GPRMC,011855,V,4022.1990,N,08249.1990,W,000.0,000.0,150470,006.7,W*6C
$GPGGA,011855,4022.1990,N,08249.1990,W,0,00,,,M,,M,,*44
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPGSV,3,1,12,12,00,000,,14,00,000,,15,00,000,,16,00,000,*7D
$GPGSV,3,2,12,17,00,000,,18,00,000,,19,00,000,,20,00,000,*7E
$GPGSV,3,3,12,21,00,000,,22,00,000,,23,00,000,,24,00,000,*7E
The following example demonstrates how to retrieve information from the first few fields of the
Global Positioning System Fix Data (GGA) line:
$GPGGA,011855,4022.1990,N,08249.1990,W,0,00,,,M,,M,,*44
Field Name Field Description
Start of Sentence $
Address Field “aaccc” where “aa” is the talker identifier mnemonic (GP for Global
Positioning System) and “ccc” is the sentence formatter mnemonic (GGA for
Global Positioning System Fix Data)
Universal Time Coordinated (UTC) “hhmmss.ss” where “hh” is hours (0 to 23), “mm” is minutes (00 to 59) and
“ss.ss” is seconds (00.00 to 59.99)
Latitude “ddmm.mm” where “dd” is degrees (0 to 89) and “mm.mm” is minutes
(00.00 to 59.99)
Latitude N/S N=North, S=South
Longitude “dddmm.mm” where “ddd” is degrees (0 to 179) and “mm.mm” is minutes
(00.00 to 59.99)
Longitude E/W E=East, W=West
The format string of all serial input channels parsing information from the GGA line should start with “$GPGGA,”
so that all other serial input strings fail to match and are ignored.