PNI TCM 2.6 - Manual (Page 12)

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 12 of 49
Using the TCM2.5/2.6
RS232 Data Output Word
The TCM2.5/2.6 sends an “output word” in ASCII across the RS232 serial link when issued the s?
(Single Output Word) command, or when in go (Continuous Sampling) mode. This data output
word may be configured by the user for the desired format and configuration. You may select either
NMEA 0183, or TCM2 standard output word formats, with the sdo= (Set RS-232 Output Word)
command.
NMEA 0183 Format
The TCM2.5/2.6 can be configured to conform to the NMEA (National Maritime Electronics
Association) 0183 specification, which describes a standard RS232 bus format for exchange of a
variety of navigation information (GPS, radar, compass, and so on). In the NMEA output format,
only compass heading information is available. Inclinometer, magnetometer, thermometer data and
the distortion detection warning are all unavailable.
$HCHDM,,M*checksum ! for magnetic heading
For example,
$HCHDM,182.3,M*checksum !for magnetic heading = 182.3 °
The checksum value is the result of XOR’ing the ASCII bytes between the ‘$’ and ‘*’ characters.
This one byte value is reported in the output word by two ASCII characters representing two hex
digits, with the most significant nibble first. For example, “...*A3” indicates that the
output word has a decimal checksum value of 163.