User's Manual

SECTION III OPERATION
SM 7063 07/97 3-29
3.16 CDU DATALOGGER PORT
The CDU supports two Data Logger Port protocol output formats. These are configurable via the
Diagnostic PC by selecting either “Data Logger Protocol” or “Event Recorder Protocol” (see Section
IV).
3.16.1 Data Logger Format
This section describes the data format output by the CDU in the case where it has been configured for
“Data Logger Protocol” from the Diagnostic PC.
The CDU transmits a data message to the data logger serial port whenever an “event” occurs. An
event is defined as a change in certain indicators on the front panel display or when a radio
transmission is received from the End Unit.
Each event produces an 11 character output from the port as defined below. Time stamping of the
message, if required, is provided by the event recorder device receiving and logging the data.
Character Position Description
1 Start Character (Line Feed)
2 ASCII Character
3 ASCII Character
4 ASCII Character
5 ASCII Character
6 ASCII Character
7 ASCII Character
8 ASCII Character
9 ASCII Character
10 Unit Transmission Indicator
11 End Character (Carriage Return)
The 8 character ASCII field can be assigned to any message that is deemed worthy of recording,
however there are a number of characters that have specific definitions in normal operation.
During normal operation, the character in position 2 is used to indicate the state of the telemetry
battery.
W = Weak
R = Replace
The character in position 3 is used to indicate the following.
*
= Marker Light Turn ON, first occurrence only.
R = Replace Marker Battery.