www.miinet.com
Moore Industries-International, Inc.
- 7 -
User’s Manual
238-760-00K
May 2019
Functional Safety Dual Input Smart HART® Temperature Transmitter
STZ
SECTION 1
Section 1 - Introduction
The Moore Industries’ Functional Safety HART Temperature Transmitter (STZ) is designed and
manufactured to provide a high level of availability for safety critical applications and for use as a
component part of a safety instrumented system.
This is the user’s manual for Moore Industries’ STZ
Programmable Smart HART Temperature
Transmitters. It contains all of the information needed to configure, install, operate and maintain
the instruments.
Overview
The STZ has the ability to accept one or two sensor inputs. The output of the STZ can be
configured to reflect either sensor 1, sensor 2, average, differential, backup, low or high select.
In backup, the STZ automatically switches to the secondary sensor input if the primary sensor
fails; either sensor can be selected as the primary sensor. This substantially increases the
overall reliability of the unit. Upon switching to the secondary sensor, an alert is displayed on
the transmitter’s LCD (HP version), and is available via the HART “additional status” diagnostic
bit. If a sensor fault occurs while the STZ is making a differential or average measurement, the
transmitter will drive the analog output upscale, downscale, preset value, or will hold last output.
The STZ has enhanced device intelligence which includes sensor drift, corrosion detection,
range alarms and device diagnostics. These can check and alert the user when thermocouples
fail unexpectedly, resistance thermometers exceed set parameters or the device has failures. A
more detailed explanation of these features is provided later in this section. For more information
on the STZ diagnostics refer to tables in Section 6.
HART 7 compliance provides device configuration via DD, HART diagnostic data and exception
based reporting. In addition a DTM is provided to enable programming and monitoring with any
FDT compliant host or program such as PACTware.
To prevent unauthorized or accidental reconfiguration of the STZ while it’s performing its safety
function, it has an added security feature to allow users to set HART communication into a Read
Only or Disable mode. In Read Only mode, the STZ responds to HART7 commands to access
device variables and diagnostic status but does not allow any changes to be made to the unit
configuration. In Disable mode, all HART messages sent to the unit are ignored and no HART
messages are sent from the unit.
The STZ HP model has an additional feature, an easy-to-read customizable display.
The STZ [DIN] is also available with an AIS option which allows direct connection of sensors
from an intrinsically safe area. See Section 3 Installation and Wiring for more information