Hart/Ams; Overview; Hart Communicator Signal Line Connections - Emerson Rosemount Analytical Oxymitter 4000 Instruction Manual

Hazardous Area Oxymitter 4000
The HART option is not protected by
energy limiting barriers. It must not be
interfaced from within the hazardous
area. The 4-20 mA cables should be
routed and the connections made out-
side the hazardous area. Note that this
is the case even when using the in-
trinsically safe version of the handheld
communicator.
7-1

OVERVIEW

The HART Communicator is a handheld com-
munications interface device. It provides a
common communications link to all microproc-
essor-based instruments that are HART com-
patible. The handheld communicator contains
an 8 x 21 character liquid crystal display (LCD)
and 25 keys. A pocket-sized manual, included
with the HART Communicator, details the spe-
cific functions of all the keys.
To interface with the Hazardous Area Oxymitter
4000, the HART Communicator requires a ter-
mination point along the 4-20 mA current loop
and a minimum load resistance of 250 ohms
between the communicator and the power
supply.
Rosemount Analytical Inc. A Division of Emerson Process Management
SECTION 7

HART/AMS

The HART Communicator accomplishes its task
using a frequency shift keying (FSK) technique.
With the use of FSK, high-frequency digital
communication signals are superimposed on
the Hazardous Area Oxymitter 4000's 4-20 mA
current loop. The HART communicator does not
disturb the 4-20 mA signal, since no net energy
is added to the loop.
The HART Communicator may be interfaced
with a personal computer (PC), providing that
special software has been installed. To connect
the HART Communicator to a PC, an interface
adapter is required. Refer to the proper HART
Communicator documentation in regard to the
PC interface option.
7-2 HART COMMUNICATOR SIGNAL LINE
CONNECTIONS
The HART Communicator can connect to the
Hazardous Area Oxymitter 4000's analog output
signal line at any wiring termination in the 4-20
mA current loop. There are two methods of
connecting the HART Communicator to the
signal line. For applications in which the signal
line has a load resistance of 250 ohms or more,
refer to method 1. For applications in which the
signal line load resistance is less than 250
ohms, refer to method 2.
Instruction Manual
IB-106-340C Rev. 4.1
July 2004
HART/AMS 7-1
7