Specifications

Section 1—Installation & Configuration Bulletin No. VVDED397044US R12/00

Trunk and Drop Cabling with Taps December 2000

Physical Network

The network bus consists of twisted-pair shielded cables that are run in a

direct path between successive nodes. The two data lines in the cable are

not sensitive to polarity; however, this bulletin follows standard wiring

conventions to facilitate maintenance.

The physical network consists of one or more cable sections, with any

section supporting up to 32 nodes at a maximum cable distance of

1,500 ft (450 m). Sections can be joined by repeater devices to extend

the network’s length and to support up to 64 nodes. The minimum cable

length between any pair of nodes must be at least 10 ft (3 m). Drop cable

length is counted twice towards the 10 ft minimum requirement. The drop

cable is a loop of the MODBUS PLUS cable. The maximum cable length

between two nodes is the same as the maximum section length of

1,500 ft (450 m).

NOTE: The ATV58 drive controller does not support a dual or redundant

MODBUS PLUS cable layout.

Figure 15: Single Cable Layout

TRUNK AND DROP CABLING WITH TAPS

Nodes are connected to the cable by means of a tap device. This provides

“through” connections for the network trunk cable and “drop” connections

for the cable to the node device.

The tap also contains a resistive termination connected by two internal

jumpers. The jumpers of the taps at each end of a cable section must be

connected to prevent signal reflections. The jumpers of taps at in-line

BP85

Bridge

Plus

= Termination Connected

End

Node

Inline

Node

Inline

Node

ATV58

Drive

Controller

= Termination Disconnected

10 ft (3 m) Cable Min.

32 Nodes Max.; 1500 ft (450 m) Cable Max.

CableTaps