Advantech ADAM-6217, User Manual

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35 ADAM-6200 User Manual
Chapter 3
H
ardware
Installation
Note! 1. The average latency from one module to another: 15 - 20 μ s:
2. Typically, the maximum cabling distance of each 100BASE-TX net-
work segment is 100 meters. Based on this limitation, the maxi-
mum total connection length of daisy chain wiring should also be
100m when auto-bypass protection active. See the following figure
as an example, the distance from the first to the second module is
50m, so is the second to third. When the power fails on second
(middle) module, the auto-bypass will activate to bridge the net-
work connection. The total distance from first to the third will
become 100m, that means the total network segment is close to its
limit.
 Furthermore, due to the characteristics of signal transmission, the
continuous auto-bypass nodes should be less than two, so that the
network communication in the daisy chain will work.
3. The purpose of the auto-bypass protection is to help users mini-
mize the damage caused by a module power outage. Note that
when a power outage occurs on ADAM-6200 modules, there is
around a 2.5 second buffer time for internally switching to the auto-
pass circuit. This means that Ethernet packets can’t reach the other
devices in the daisy-chain for around 2.5 seconds. The valid con-
nection duration after the auto-bypass function is enabled is at
most around four days, otherwise, the Ethernet communication will
be interrupted until power is restored.