DH-485 Network Capability
The MicroLogix family of
micro-PLC's comes with network connectivity using the DH-485
peer-to-peer network. DH-485 is the same network used by all of
Allen-Bradley's popular SLC™ 500 programmable controllers. The
DH-485 network offers:
-
intercommunication of
up to 32 devices
-
peer-to-peer
capability
-
the ability to add or
remove nodes without disrupting the network
-
maximum network
length of 1219m (4000 ft), can be extended to 2438m (8000 ft)
with 2 AIC+ units
To connect a MicroLogix
controller to a DH-485 network, use the
AIC+ (Advanced Interface Converter) to bridge the RS-232 port to
the DH-485 network.
The peer-to-peer network
capability of the MicroLogix line means any of these
micro-controllers on a DH-485 network can initiate or respond to
communications with any other device on the network. With the
ability to initiate communications, any MicroLogix controller can
serve as a single "initiator" (also referred to as a "master" or
"parent") on the network.

What's more, DH-485
peer-to-peer capability keeps network traffic at a minimum, by
allowing each micro to initiate unsolicited communications. This
eliminates the need for a dedicated "initiator" controller, which
can tie up the network with constant polling of the "responder"
(also referred to as "slave" or "child") controllers. Most
competitive micros have "initiator" or "responder" functionality
only, meaning they can only respond to interrogation from a single
"initiator" controller.
You can create an all-MicroLogix
network for distributed control with up to 32 nodes, enabling
controllers to exchange program information such as data, counter
and timer pre-sets, etc. You can include other devices running
DH-485 as well, like operator interface products (DTAM Micro, DTAM+
PanelView 550 and 900), bar code products and drives on this
all-micro network. Also, a single personal computer can program all
of the MicroLogix units on the network.
You may also add
MicroLogix controllers to any of the multitude of established or
planned SLC 500 DH-485 networked systems. This allows for the use of
very cost-effective dedicated micro-controllers on small machines,
while continuing to enable the exchange of data with the SLC 500
processors on the network.

DH-485 Connectivity and
Device Isolation
The 1761-NET-AIC networking device
provides
DH-485 network access from any DH-485 compatible device that has
a RS-232 port, including all MicroLogix controllers, SLC 5/03 and
5/04, and PanelView 550 and 900. In addition, the device provides
isolation between all ports for a more stable network and protection
for connected devices.
The unit is DIN rail or panel
mountable and is industrially hardened. A variety of cables are
provided for easy connectivity between the AIC+ and other
Allen-Bradley products.
Features
- two isolated RS-232 connections
(one 9-pin D-shell and one 8-pin mini DIN)
- a RS-485 6-pin Phoenix
connection
- accepts power via 8-pin Mini
DIN from the MicroLogix 1000 or an external power connection
- compatibile with existing SLC
DH-485 networks that use 1747-AIC's
- auto baud rate capability for
ease of system set-up
- diagnostic LEDs for monitoring
port and network activity
Typical Applications
- Connecting MicroLogix 1000
micro-PLCs to a DH-485 network
- Connecting the RS-232 port of
an SLC 5/03 or 5/04 Processor to a DH-485 network
- Connecting a personal computer
to a DH-485 network
- Extending DH-485 networks to
2,438 meters (8,000 ft)
- Connecting a three node DH-485
network using two RS-232 devices and one DH-485 device (SLC 500
Fixed, 5/01, 5/02, etc)
Specifications
24Vdc Power Source Requirement |
20.4 - 28.8Vdc |
Current Draw |
120mA 200mA maximum inrush
current |
Internal Isolation (see below) |
500Vdc |
Operating Ambient Temperature |
-0 to 60 C (32 to 140F) |
Agency Certification |
UL 508
CSA C222
CE compliant for all applicable directives |
DH-485 or DF1
max. number of nodes=
max. length=
max. number of "ganged" multidrop networks=
|
32 per multidrop network
1,219m (4,000 ft per multidrop network)
2 |
Isolation Between All Ports and
Power Supply Terminals
Mounting Dimensions
|