www.miinet.com
Moore Industries-International, Inc.
- 123 -
User’s Manual
238-741-00K
May 2019
Programmable Smart HART Temperature Transmitter
THZ
3
/ TDZ
3
SECTION 7
Multidrop Networks Save Wiring Costs
Any combination of up to 15 THZ
3
and TDZ
3
smart transmitters connect in parallel onto a
HART digital communication link (Figure 7.3). This means you can use a single loop, instead
of 15 separate loops, to connect multiple transmitters. In a multidrop network, the transmitter’s
measured process variable is output digitally, so the 4-20mA signal (set to 4mA) is not used.
A HART-based control system uses each transmitter’s individual address (1-63) to configure or
view the transmitter’s data. A HART Communicator or a PC can be used in this configuration to
access information from, or transmit configuration information to, the transmitter from anywhere
on the HART loop.
–
+
–
+
–
+
HART-
Based
DCS
(Primary
Master)
HART
Communicator
(Secondary
Master)
THZ
(HART
Slave)
THZ
(HART
Slave)
TDZ
(HART
Slave)
3
3
3
16 Individual Temperature Sensors
SMART HART
TEMPERATURE
TRANSMITTER
DUAL SENSOR
ADDR
TDZ
3
Figure 7.3.
Save time and money by networking up to 15 of our Smart HART transmitters onto a single digital data link.
HART Master/Slave Structure
To implement two-way communications between the transmitter and the device configuring or
receiving its information, the transmitter operates in a HART
Master/Slave structure.
The THZ
3
or TDZ
3
is a Slave (or Slaves in a multidrop network). There can be two Masters per
system: a Primary Master and a Secondary Master. In the majority of applications, the Master is
a HART Hand-Held Communicator, but it can also be a HART-based control system. Operating
in HART’s Poll/Response (Normal) Mode, the HART Master polls the transmitter two times per
second to access the current process variable status, send setup data to the transmitter, or
remotely view its identification, configuration and diagnostic data.
