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38 Issue
Number:
3
9 Advanced
Features
9.1 Network
Loss
Trip
Unidrive: #20.11
0 = trip disabled
16 to 992 = trip delay time (in ms)
The Profibus-DP interface counts the number of valid network cycles
received in a time period specified by #20.11. The trip is triggered if no
messages are received in a given sample period, and messages were
received in the previous sample period. The default setting for #20.11
is 48ms. The UD70 Global Run-Time Trips also have to be enabled by
setting #17.14 to 1.
Profibus-DP stops
communicating here
Time
(ms)
Messages
per sec
Sample
points
#20.11
Unidrive trips
on "tr60"
As can be seen from the diagram, the actual time from network loss to
Unidrive trip will range from #20.11 ms to 2 * #20.11 ms. If the trip time
is set too low, spurious network loss trips may be seen.
The actual network loss trip time depends entirely on the number of
messages per second being received under normal operation. As a
rough guide, the network loss trip time (#20.11) should be set such that
a minimum of 5 messages will be received in any given sample period
under normal operating conditions.
NOTE
The network loss trip delay is specified in ms, but the time set will be
rounded up to the nearest multiple of 16ms. Hence, if the time delay is
set to 100ms, this will be rounded up to 112ms.