The ETB control service functions “leading” and “confirmation/correction” determine the content of the operational train directory. The computation of the operational train directory is a function on each ECSP connected to ETB0, which is responsible to create and to maintain the operational train directory as defined in 5.3.3.
The principal operation of the operational train directory computation is shown in Figure 26.
Figure 26 – Operational train directory computation block diagram
Input to the operational train directory computation is the collection of ETBCTRL telegrams received from all the ECSPs. This includes the own (local) ECSP as well as the remote ECSPs (= all the others except the own ECSP).
Those ETBCTRL telegrams might for instance be stored to an ETBCTRL traffic store for further processing. The operational train directory computation checks the content of the ETBCTRL traffic store for changes with respect to leading vehicle information, correction information and trnTopoCnt.
If a change is detected, a new operational train directory shall be computed in accordance to the rules given later in this subclause and the confirmation status of the TTDB shall be updated (if needed). In addition, actualized input to the ETBCTRL telegram sent by the local ECSP shall be provided.
6.4.5.2 State diagram
The operational train directory computation process is defined by the state diagram shown in Figure 27 and further described in Table 28 to Table 30.
IEC
operational train directory computation
Operational train directory
Train directory
TTDB confirmation status
ETBCTRL receiver Received
ETBCTRL packet
ETBCTRL
ETBCTRL ETBCTRL Traffic Store
ETBCTRLSent packet
from other ECSP
from own (local loop-back)ECSP
ETBCTRL sender
Input from local ECSC (ETB control service calls)
Figure 27 – ETBCTRL processing state diagram Table 28 – ETBCTRL processing – triggers
Trigger Description
startOpTrnDirProcess Start processing of the operational train directory, triggered by the train directory computation state machine, see .5.3.2.
stopOpTrnDirProcess Stop processing of the operational train directory, triggered by the train directory computation state machine, see .5.3.2.
etbCtrlReceived ETBCTRL telegram received
etbCtrlTimeOut ETBCTRL telegram timeout
Table 29 – ETBCTRL processing – guards
Guard Description
[trnTopoCntValid == TRUE] ETBCTRL telegrams have been received from all active ECSP listed in the local train directory with cstTopoCnt != 0 and all received valid ETBCTRL telegrams (including own ETBCTRL telegram) have a value of trnTopoCnt identical to the trnTopoCnt value stored in the local train directory.
Table 30 – ETBCTRL processing – actions
Action Description
opTrnDirReset The operational train directory shall be reset as defined in 6.7.3 (trigger event ‘opTrnDirReset’)
enableEtbCtrlRx Prepare to receive ETBCTRL telegrams from all consist ECSPs listed in the train directory with a valid cstTopoCnt and establish individual timeout supervision for each of those consist ECSPs.
Set receive timeout to a value of (3,0 ± 0,1) s.
IEC
WaitForEtbCtrl
startOpTrnDirProcess /enableEtbCtrlRx /startEtbCtrlTx
/trnTopoCntValid = FALSE
etbCtrlReceived /processEtbCtrl /checkCompleteness
etbCtrlTimeout /handleTimeout
EtbCtrlSetUp
[trnTopoCntValid == TRUE]
/compChange
etbCtrlReceived /processEtbCtrl /processOpTrnDir
etbCtrlTimeout /handleTimeout /processOpTrnDir stopOpTrnDirProcess
/opTrnDirReset
stopOpTrnDirProcess
Action Description
The timers shall be activated after the reception of the first related ETBCTRL telegram.
startEtbCtrlTx Start to cyclically send ETBCTRL telegrams Cycle time: (0,5 ± 0,1) s
Once ETBCTRL telegram transmission is started it can run forever, meaning that it needs not to be stopped if trigger
‘stopOpTrnDirProcess’ activates.
processEtbCtrl Received ETBCTRL telegrams shall be processed as follows:
1) ETBCTRL telegrams originating from an ECSP which is not listed in the train directory (unknown cstTopoCnt value) or listed with cstTopoCnt = 0 shall be discarded.
2) ETBCTRL telegrams with a parameter ‘trnTopoCnt’ value dífferent to the value of parameter ‘trnTopoCnt’ stored in the local train directory shall be discarded.
3) Control flags and other relevant parameters from non-discarded ETBCTRL telegrams shall be memorized, e.g. stored in the traffic store
checkCompleteness trnTopoCntValid shall be set to TRUE if (non-discarded) ETBCTRL telegrams have been received:from all ECSPs listed in the train directory with cstTopoCnt != 0 except from those ECSPs which are marked as being timed out.
processOpTrnDir Start operational directory computation process:
• The leading vehicle function state machine as defined in 6.5.
• The confirmation/correction function state machine as defined in 6.6
• Supporting operations as defined in 6.7
This computation process can be executed event driven (as indicated in the state diagram) or cyclic.
handleTimeout Mark the related source consist as being timed out.
Set the (locally stored) control flags of the related source ECSP to deferred values (e.g. in traffic store).
Deferred values are defined:
• in 6.5 for the leading function
• in 6.6 for the confirmation/correction function
• in 6.8 for the sleep mode function
compChange Trigger a ‘compChange’ event:
• in 6.5 for the leading function
• in 6.6 for the confirmation/correction function