Heinzmann Triton OMD, Manual

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7 General communication functions overview
Triton OMD CAN protocol / Rev.-No. 03 21
7.3 Network time synchronization
Master is responsible for time synchronization of each individual sensor in the network. The
first synchronization is performed during automatic ID assignment procedure, when master
sends its current time stamp within telegram kNetworkIDDistributRequest .
After this, master sends common designated message
kNetworkTimeSynchComman
via CAN1
and CAN2 every 600s. Furthermore, master additionally sends kNetworkTimeUpdateCom-
mand message if its time and date setting were changed by the user.
The messages are distributed in the network by sensor devices themselves.
Data items within
kNetworkTimeSynchCommand
and
kNetworkTimeUpdateCommand
mes-
sages:
•
Masters time and date (Unix time).
For the cases when OMD sensor is used with third party superordinate system instead of
OMD evaluator, it is important to take into consideration specific feature for correct time syn-
chronization of the whole network. This issue is especially critical for data logging functional-
ity of sensor device.
The transmission of telegrams
kNetworkIDDistributRequest
,
kNetworkTimeSynchCommand
,
kNetworkTimeUpdateCommand by the master must be triggered by second counter increment
event of master clock, e.g. on the edge of new second. Even when all the other condition for
transmission are fulfilled, master unit should wait for new second edge before sending one of
these messages.
7.4 Individual sensor configuration
After successful automatic ID (node number) assignment procedure each sensor starts com-
munication to master.
Sensor device makes the decision about its configuration validity (or invalidity) on the base of
comparison of masters configuration parameter set CRC value (received during automatic
node number assignment procedure) to own CRC calculated trough actual configuration pa-
rameter set.
In case of configuration parameter set invalidity on individual sensor side, master receives
cyclic service message
kSensorCRCInvalidReport
from corresponding sensor. This means
that master should broadcast its configuration parameter set to the sensor.
After successful configuration parameter set update with new values, sensor recalculates CRC
through updated parameter set. In case new CRC value is equal to masters configuration pa-
rameter set CRC value, sensor stops transmission of
kSensorCRCInvalidReport
message and
start reporting operational data to the master.