Multidrop Communication - Emerson Rosemount 3051S Series Reference Manual

Rosemount 3051S Series
MULTIDROP
COMMUNICATION
Figure 3-10. Typical Multidrop
Network
3-30
AMS v7.0
Right click on the device and select "Configure" from the menu
1. In the "HART" tab, use the drop down menu to select "Burst Mode ON or
OFF." For "Burst option" select the desired properties from the drop down
menu. Burst options are as follows:
• PV
• % range/current
• Process vars/crnt
• Process variables
2. After selecting options click Apply.
3. After carefully reading the warning provided, select yes.
Multidropping transmitters refers to the connection of several transmitters to a
single communications transmission line. Communication between the host
and the transmitters takes place digitally with the analog output of the
transmitters deactivated. With smart communications protocol, up to fifteen
transmitters can be connected on a single twisted pair of wires, or over leased
phone lines.
Multidrop installation requires consideration of the update rate necessary from
each transmitter, the combination of transmitter models, and the length of the
transmission line. Communication with transmitters can be accomplished with
Bell 202 modems and a host implementing HART protocol. Each transmitter
is identified by a unique address (1–15) and responds to the commands
defined in the HART protocol. Field Communicators and AMS can test,
configure, and format a multidropped transmitter the same way as a
transmitter in a standard point-to-point installation.
Figure 3-10 shows a typical multidrop network. This figure is not intended as
an installation diagram.
NOTE
A transmitter in multidrop mode has the analog output fixed at 4 mA. If a
meter is installed to a transmitter in multidrop mode, it will alternate the
display between "current fixed" and the specified meter output(s).
HART
Modem
Reference Manual
00809-0100-4801, Rev EA
Power
Supply
August 2010
.