Interruption Of The Transmission Path - Leuze electronic DDLS 200 Series Original Operating Instructions

DeviceNet / CANopen
9.6

Interruption of the transmission path

Response upon interruption of the optical transmission path
Segment 1 Segment 2
Interruption of the optical transmis-
sion path
DT1 DT2
TN1 TN4
TN2 TN3
Figure 9.11: Interruption of the optical transmission path
If only data fragments are received as the result of the interruption in the optical transmission path,
these are detected and are not transmitted to the CAN bus segment. The connected participants are
not informed of an interruption in the optical transmission path via the protocol (switching output is ac-
tivated). Data transmitted during the interruption is lost. The primary protocol is responsible for man-
agement of the subscribers. For this reason, the monitoring mechanisms of the primary protocol
should be used (Node/Life Guarding, Heartbeat, ...).
Monitoring of participants
If a DDLS 200 optical data transmission system is used in a DeviceNet or CANopen system, it is ben-
eficial to monitor all participants to determine whether they are still participating in data exchange. The
following mechanisms are available for this purpose:
Heartbeat
Participants transmit cyclical heartbeat messages. If a message is not received for a certain period of
time, this is detected by the connected participants as a "Heartbeat Error".
Node / Life Guarding (CANopen)
The NMT Master (Network Management Master) cyclically queries all participants and expects an an-
swer within a certain period of time. If this response is not received, a "Guarding Error" is detected.
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