User's Manual

SECTION III OPERATION
SM 7063 07/97 3-30
The character in position 4 is used to indicate the following:
< = Reply from End Unit is pending.
+ = Reply from End Unit is pending.
! = Emergency Brake Application has been transmitted.
I = The End Unit is operating in One-way mode.
U = The CDU is in two-way mode but has not been armed.
The character in position 5 is used to indicate status of the End Unit brake valve drive circuitry as
follows:
V = Brake Valve Drive Circuit Failure.
The character in position 6 is used to indicate motion and direction.
> = Indicates Forward direction
< = Indicates Reverse direction
^ = Indicates Moving (after forward or reverse have occurred)
- = Indicates Stopped
The characters in positions 7, 8, and 9 are used indicate the current brake pressure value. The range
is from “ 0” psig (leading zeros are space characters) to “125” psig.
The Unit Transmission Indicator in position 10 is used to indicate whether the datalogger port output
message was the result of a change in CDU display status or as a result of a status update message
received from the End Unit.
“ “ = The event was the result of a change in CDU display status
# = The event was the result of a status update message received from the End Unit.
A typical data logger message would be:
“ R
*
74# “
meaning that:
1. the Telemetry battery is low and will need to be replaced soon,
2. the Marker Light has just come on,
3. the brakepipe pressure is 74 psig,
4. the event was initiated as the result of a spontaneous status update message from the End
Unit or a status update message due to a communications test (manual or automatic).