Rockwell Automation 1766-Lxxxx MicroLogix 1400 Programmable Controllers User Manual - Manual (Page 223)

Rockwell Automation Publication 1766-UM001H-EN-P - May 2014 183
Appendix
E
Connecting to Networks via RS-232/RS-485
Interface
The following protocols are supported from the RS-232/485 combo
communication channel (Channel 0) and the RS-232 communication channel
(Channel 2):
• DF1 Full Duplex
• DF1 Half-Duplex Master/Slave
• DF1 Radio Modem
• DH-485
• Modbus RTU Master/Slave
• ASCII
• DNP3 Slave
RS-232 Communication
Interface The communications port on Channel 0 of the MicroLogix 1400 controller
utilizes a combined, isolated RS-232/485 interface. RS-232 and RS-485 are
Electronics Industries Association (EIA) standards that specify the electrical and
mechanical characteristics for serial binary communication. They provide a
variety of system configuration possibilities (RS-232 and RS-485 define electrical
connection characteristics,
not protocols).
The MicroLogix 1400 controller supports an additional, non-isolated RS-232
interface on Channel 2. One of the biggest benefits of an RS-232 interface is that
it lets you integrate telephone and radio modems into your control system (using
the appropriate DF1 protocol only, not DH-485 protocol), but it is for
point-to-point connections only between two devices.
RS-485 Communication
Interface The RS-485 interface supports connection of devices in a multidrop hard-wired
configuration using DH-485, DF1-Half Duplex, Modbus, or DNP3 protocols.
Also, the RS-485 interface supports connection in a multidrop hard-wired
configuration using ASCII protocols.
DF1 Full-Duplex Protocol DF1 Full-Duplex protocol provides a point-to-point connection between two
devices. DF1 Full-Duplex protocol combines data transparency (American
National Standards Institute ANSI - X3.28-1976 specification subcategory D1)
and 2-way simultaneous transmission with embedded responses (subcategory
F1).