Trans-Cal SSD120 M Series, Installation And Calibration Manual

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1.5 Serial Communication Format
Model SSD120-(XX)M and carries out serial communication
asynchronously with the “Start/Stop” system. This system puts a start bit
at the head of a character, and then in turn adds data bits, a parity bit, and a
stop bit. The specifics of the protocol are determined by user selection, see
§4.4 , and Table V.
1.6 Serial Communication Protocol
The serial data protocol is user selectable via software see §4.4 . If the
installation calls for two separate protocols to be transmitted on the serial
data ports the second protocol may be software assigned. The following
list of protocols is referred to in
§4.4 .
Protocol 1 which is compatible with UPS Aviation Technologies’ Apollo
(IIMorrow) Navigation devices. At a baud rate of 1200 bps the encoder
sends a seventeen byte message beginning with # AL, then a space
followed by five altitude bytes ; the letter "T" and the number "25"; two
checksum bytes and a carriage return.
An example of a serial message for UPS AT Apollo devices:
Message: Definition:
#AL +25D8
r
Altitude 800 feet
Protocol 2 is compatible with some navigation devices manufactured by
Trimble and Garmin. At a baud rate of 9600 bps the encoder sends a ten
byte message. The message begins with ALT followed by a space and five
altitude bytes; concluding with a carriage return. Examples of serial
messages for Trimble or Garmin devices:
Message: Definition:
ALT 10500
r
Altitude 10,500 feet