Trunk Line/Drop Line And Maximum Cable Length - Toshiba 2000 V Series Manual

Chapter 1 Overview of the Devicenet Module
1.2.2

Trunk line/drop line and maximum cable length

1
4
The DeviceNet specifications cover the thick cable and the thin cable. For the details,
see DeviceNet Volume I. Cables conforming with the thick cable and thin cable
standards are now commercially available. Buy ones which meet the configuration of
your network (Details are explained in 3.6 Network Components).
(1) Trunk Line
A DeviceNet trunk line consists of a thick cable or a thin cable (mixed use is also
possible). The thin cable is easy to install because it is more flexible than the thick
cable. The thick cable, however, allows longer network cabling than the thin cable.
The maximum trunk line length varies depending on the type of cable used and the
communication rate of the network. For details, see (3) Maximum Network Length.
(2) Drop Line
A DeviceNet drop line consists of a thin Cable. Table 1-1 shows the length of drop
lines and the total length per network. Nodes can be arranged on drop lines in a
short drop line configuration, multi-drop configuration, or branch configuration.
Figure 1-4 shows how to calculate the drop line length and the total length for each of
these configurations.
Table 1-1 Maximum Drop Line Length
Communication Rate
125kbps
250kbps
500kbps
Branch configuration
Node 45
Node 35
Multiport tap
i
Node 30
Node 40
Terminator
No drop line configuration
Node 0
Node 5
Individual drop line length : a <= 6m, b <= 6m, c <= 6m, d <= 6m
Total extension of drop lines : a + b + c + d + e + f + g + h + i
Figure 1-4 Example of Calculating Drop Line Length
Drop Line
6m
g
f
Tap
h
Tap
Multiport tap
a
b
Node Node
Node
10 15
20
Short drop line configuration
(Short drop line configuration)
e <= 6m (Multi-drop configuration)
f + g <= 6m, f + h <= 6m, f + i <= 6m (Branch configuration)
model 2000 DeviceNet Module Manual (DN611/DN611A)
Total Extension per Network
156m
78m
39m
Tap
Terminator
Node 50
e
Node 55
Node 60
Multidrop
configuration
d
c
Node
25