ETTC'2003 - SEE

TD:
“0” means that the parameters are producing by the acquisition systems
“1” means that the parameter are producing by onboard computer “telemetry”
GS: Global synchronisation status
“1” synchro loss.
“0” ok.
LS: Local synchronisation status
“1” synchronisation loss.
“0” ok.
The SEQ_NUM field
Each key has his own SEQUENCE NUMBER counter which shall be incremented before every
KEY creation.
It’s a 16 bits circular counter.
This field is controlled by all IENA packet decoders to watch the lost packets in the FTI
network.
The PARAMETERS field
The PARAMETERS field is a set of parameters that IENA system produce and transmit to receivers
across IENA network. A parameter is identified by the ID field, it contain useful data or measures.
The “Standard parameter” is used to carry either analog, status or bus parameters.
The “ Message parameter” is used to carry bus (RS232/422/485, ARINC429, AFDX, CAN …) frame
parameters.
Standard Parameter
The general structure of standard parameter is given hereafter :
ID
1 WORD
DELAY
1 WORD
IENA STANDARD PARAMETER
DATA PARAMETER (1 to 8 Words)
WN W.. W2 W1
a) ID field identifies the parameter in one IENA packet. This is an optional field, this structure is
defined by the data base. The ID field is unique in all programming version of test installation.
b) DELAY field specify the delay ( in µs) between the packet creation time and parameter
acquisition time.
The allowed values are from 0 to 65535 µs.
Parameter time tag = packet creation TIME + parameter DELAY.
This is an optional field which is defined by the data base.
c) DATA field is dedicated to carry either an acquired or internal parameter. It’s a mandatory field.
The number of word which constitutes the data is given by the data base.
4