Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 208)

Publication AG-UM008C-EN-P - February 2005
6-4 Configuring MicroLogix 1000 Controllers
Isolated Connections
MicroLogix controllers should be installed using an Optical Isolator.
The AIC+, catalog number 1761-NET-AIC is recommended. Example
installations are shown below. Using the AIC+ also provides a
communication active LED, which is not standard on the
MicroLogix 1000 controller.
Figure 6.3 Isolated Connections Using AIC+
Automatic Protocol
Switching The MicroLogix 1000 Series D (and higher) discrete and
MicroLogix 1000 analog controllers perform automatic protocol
switching between DH-485 and the configured DF1 protocol. The
controller cannot automatically switch between DF1 full-duplex and
DF1 half-duplex slave. With DF1 configured as the primary protocol
(S:0/10=0), this feature allows you to switch from active
communication on a DF1 half-duplex network to the DH-485 protocol
to make program changes.
Simply disconnect the MicroLogix controller from the half-duplex
modem and connect it to your personal computer. The controller
recognizes the computer is attempting to communicate using the
DH-485 protocol and automatically switches to it. When your program
changes are complete, you can disconnect your computer, reconnect
the modem, and the controller will automatically switch back to DF1
half-duplex slave protocol.
Optical Isolator
1761-CBL-PM02
MicroLogix Controller
Personal Computer
Modem
User supplied modem cable
(same as SLC modem cable.
See page 4-3).
1761-CBL-AM00
or
1761-CBL-HM02
24V dc (Not needed in this
configuration since the
MicroLogix 1000 provides
power to the AIC+ via port 2).
(1761-NET-AIC)
or
1761-CBL-AP00
Note: In an actual application, only the personal computer
or the modem would be connected to AIC+ port number 1
at any given time.