20 The Interface Solution Experts
TRZ
Communication Speed and Format
The speed of the HART transmission is 1200 baud.
The time delay between a master initiating a request
for data from a slave and the slave receiving and ac-
knowledging the request depends upon which com-
mand is issued. Generally, a master can poll a slave
2-3 times per second.
The byte structure of the HART signal is:
1 Start Bit, 8 Data Bits, 1 Odd Parity Bit, 1 Stop Bit.
Maintenance
Moore Industries suggests a quick check for terminal
tightness and general unit condition every 6-8 months.
Always adhere to any site requirements for pro-
grammed maintenance.
Customer Support
Moore Industries is recognized as the industry leader
in delivering top quality to its customers in products
and services. We perform a battery of stringent qual-
ity assurance checks on every unit we ship. If any
Moore Industries product fails to perform up to rated
specifications, call us for help. Our highly skilled staff
of trained technicians and engineers pride themselves
on their ability to provide timely, accurate, and practi-
cal answers to your process instrumentation ques-
tions.
Factory phone numbers are listed on the back cover
of this manual.
If problems involve a particular TRZ, there are several
pieces of information that can be gathered
before
you call the factory
that will help our staff get the an-
swers you need
in the shortest time possible.
For
the fastest service, gather the complete model and
serial number(s) of the problem unit(s) and the job
number of the original sale.
Operation
Once programmed, calibrated, installed, and supplied
with the correct power, TRZ transmitters begin to op-
erate immediately. Depending upon environmental
conditions, they can be expected to operate unat-
tended for extended periods of time.
HART Protocol
This section of the manual gives an overview of the
HART format used by TRZ modules during operation.
Use the information in this section to process the data
provided by the module(s) during operation. For more
information on the HART protocol, contact the HART
Foundation at:
The HART Communication Foundation
9390 Research Blvd, Suite 1-350
Austin, TX 78759-6540 U.S.A.
(512) 794-0369
www.ccsi.com/hart
Device Types
To implement two-way communication between the
TRZ and the device being used to configure it or re-
ceive its information, the TRZ operates in a HART
Master/Slave structure. The TRZ is the Slave (or
slaves in a multidrop network).
There can be two Masters per system: a Primary
Master and a Secondary Master. Masters are typi-
cally either a HART Hand-Held Communicator or a
HART-based control system.
In many applications, the Primary Master is a HART
Hand-Held Communicator. The communicator is
used solely as a configuration tool to set up the TRZ,
periodically view its real-time process measurement,
or view its operating and diagnostic information from a
loop termination point.
Digital Signal
One of the advantages of the HART protocol is that
the digital information is conveyed by the same wires
used to output the 4-20mA signal. After being polled
by the master, the TRZ responds to the inquiry by
modulating the 4-20mA current 0.5 mA above or be-
low the output signal. 1200 Hz represents 1 and
2200 Hz represents 0.
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