Rockwell Automation 1770-HT8 SMART TRANSMITTER - Manual (Page 17)

Introducing the Smart Transmitter
Chapter 1
Interface
1-6
Full Duplex Communications
With DF1 full duplex systems, you can communicate directly to a single
Smart Transmitter Interface. No programmable controllers are
necessary—just a computer running the appropriate software, the HART
field devices, and the Smart Transmitter Interface between them. The host
computer and the Smart Transmitter Interface should be connected with
either an RS-232 cable for distances equal to or less than 50 feet, or two
modems for distances greater than 50 feet. (See Figure 1.6 and Figure 1.7.)
This gives end users with less complex applications, inexpensive access to
HART field devices and to the advantages of the HART protocol.
Figure 1.6
Full Duplex Communication with no Modem
90050
HART
Field
Devices
RS-232 CABLE
HOST COMPUTER
Smart
Transmitter
Interface
Figure 1.7
Full Duplex with Modems
90049
HART
Field
Devices
RS-232 CABLE
HOST COMPUTER
Smart
Transmitter
Interface