particular interface is cleared whenever a monitoring packet is received or if a diagnostic
interrogation succeeds. A cleared fault generates an
alarm cleared
.
Both nodes independently report failures and faults. It is possible to have a failure but not a fault.
e converse is not true. It is possible for only one twin to report a failure. For example if either
interface has failed the active node will not receive any round trip monitoring packets so it will
report a failure on both interfaces. However it will only report a fault on one. In the same event
the inactive twin will report a failure on only one interface not both. e inactive will report a
fault on one interface.
Alternatively if one interface fails and then some time later the other interface fails, the initially
active twin will not diagnose the second fault. e initially inactive twin, however, will diagnose
the second fault. erefore in order to fully characterize the failure and fault state of a redundant
pair the state of both devices must be examined. Moreover, the monitoring application is on the
LON side. In the event of an IP failure the alarm SNVT sent by the active node may not be
received by a monitor HMI on the IP side. Although the alarm is sent out both sides, the IP side
has failed so the alarm can’t propagate on the IP side and the inactive twin may not have switched
to forwarding mode in time to forward the alarm packet. Nevertheless, the inactive device will
also detect the fault and its alarm will propagate.
1
.
7.2. Status SNVT
e twin monitoring application has a status SNVT type 93. If bound, the status SNVT is
propagated either on a timer, or when it is updated by the monitoring application, or both, or
neither. If
propagate on update
is off and the update time is zero then the status SNVT will
never be scheduled for propagation. In this case the only way to read the status SNVT is to poll it.
If
propagate on update
is off and update time is non zero then the status SNVT will propagate
at an interval specified by the update time. If
propagate on update
is on and update time is non
zero then the status SNVT will propagate both on the update time interval and anytime the status
is changed. If the update time is zero and
propagate on update
is on then the status SNVT will
only propagate when changed or updated by the monitoring application. Typically the status is
updated when the twin mode state changes.
e fields used in the status SNVT are as follows:
comm_failure
is set to 1 when there is either a monitoring failure or a diagnostic detects a fault.
comm_failure
is not set to 0 until all failures and faults have cleared.
reserved2
is set based on the system state. See the following table.
Bit values for reserve2 status byte (big endian)
Bit
Value
7
1 Active State, 0 Inactive State
6
1 Forwarding, 0 Dropping
5
1 Repair State, 0 Not Repair State
4
1 Diagnostic State, 0 Not Diagnostic State
3
1 IP side failure, 0 No IP side failure
2
1 LON side failure, 0 No LON side failure
-17-
Summary of Contents for GRouter3
Page 1: ...GRouter3 Single Port 709 1 852 Router User Guide 3 03 2007 02 10...
Page 13: ...Fig 1 8 Unicast Fig 1 9 Mulitcast 13...
Page 22: ...Fig 1 14 Power port detail e le most pin of the rightmost connector is chassis ground 22...
Page 56: ...Fig 2 23 Contacts Page 56...
Page 60: ...Fig 3 2 Initial LonMaker Drawing Fig 3 3 Router Channel Setup 60...
Page 66: ...Fig 3 9 New Virtual Functional Device Dialog Fig 3 10 Functional Blocks NV Shapes Dialog 66...
