Rockwell Automation 1770, D17706.5.16 Ref Mnl DF1 Protocol Command - Manual (Page 23)

1–6 Network Layers
Publication 1770Ć6.5.16 - October 1996
DH485 Link
A DH485 link is a low cost, peer-to-peer programming and
data-acquisition link for a variety of Allen-Bradley products.
DH485 topology is similar to DH and DH+ topology. You can
connect as many as 32 nodes to a DH485 link.
The DH485 link is based on the Electrical Industries Association
(EIA) Standard RS-485 Electrical Signalling Specification.
A variety of Allen-Bradley products (including SLC 500 controllers,
1784-KTX, 1747-KE, 1770-KF3, and operator interface devices) act
as token-passing masters on the DH485 link. This link also supports
a respond-only mode for low-level devices on the link, such as
Allen-Bradley bar code decoders.
A DH485 link implements peer-to-peer communication with a
token-passing scheme to rotate link mastership among the nodes
connected to that link.
DH485 link
T53 programming terminal with a
1784ĆKTX card installed and running
6200 series software
PLCĆ5 processor
SLC 5/04
processor
notebook compute
with 1784ĆPCMK
1747ĆAIC
RSĆ232/RSĆ485
converter
1747ĆAIC
1747ĆPIC À
channel 0
channel 1
DH+ link
DTAM Plus
operator
interface
1747ĆAIC
PanelView 550
operator terminal
1770ĆKF3
1747ĆAIC
SLC 5/01 processor
in 17Ćslot modular system
SLC 5/03
processor
to remote
I/O chassis
remote I/O link
À To connect an SLC 5/04 to a 1747ĆPIC,
use a 9Ćpin (male) to 25Ćpin (female) adapter.
1747ĆSN
1747ĆAIC
SLC 500
fixed 30ĆI/O
controller with
expansion chassis