Honeywell STT25D User manual

Product of France Issue 6 - 02/00 EN1I-6190
STT 3000 - Series STT250
Smart Temperature Transmitter
Models STT25D, STT25H, STT25M
Operator Manual

Smart Temperature Transmitter STT250 – Operator Manual i
TABLE OF CONTENTS
1. OVERVIEW ..........................................................................................................1
1.1 INTRODUCTION ................................................................................................1
2. TECHNICAL SPECIFICATIONS......................................................................2
2.1 ENVIRONMENTAL CONDITIONS........................................................................2
2.1.1 Physical Specifications.........................................................................2
3. THEORY OF OPERATION................................................................................3
3.1 BASIC OPERATION...........................................................................................3
3.2 CONFIGURATION TOOLS..................................................................................4
3.2.1 Smart Field Communicator (SFC)......................................................4
3.2.2 HART Communicator (model 275).....................................................4
3.2.3 Smartline Configuration Toolkit (SCT)...............................................5
4. BENCH CHECK INSTALLATION/COMMISSIONING.................................7
4.1 UNPACKING.....................................................................................................7
4.2 EQUIPMENT......................................................................................................7
4.3 INSTALLATION ..................................................................................................7
4.4 GROUNDING AND SHIELDING TECHNIQUES.....................................................8
4.5 STT250 CONFIGURATION ..............................................................................8
4.5.1 Analog Output Configuration (based on STS103)..........................8
4.5.2 DE Digital Output Configuration.......................................................11
4.5.3 HART Configuration...........................................................................12
4.6 MOUNTING....................................................................................................14
4.6.1 DIN Rail Mounting ..............................................................................14
4.6.2 Mounting Module in Housing............................................................14
4.7 COMMISSIONING...........................................................................................18
4.8 START UP.....................................................................................................18
5. MAINTENANCE/TROUBLESHOOTING..................................................19
5.1 MAINTENANCE..............................................................................................19
5.2 TROUBLESHOOTING......................................................................................19
5.2.1 Troubleshooting with SFC.................................................................19
5.2.2 Troubleshooting with HART communicator...................................22
5.3 RECOMMENDED PARTS................................................................................24
5.4 WIRING AND INSTALLATION DRAWINGS NUMBERS.......................................25
6. INDICATION METERS ................................................................................27
6.1 INTRODUCTION .............................................................................................27
6.2 CONNECTION INFORMATION .........................................................................27
6.3 INSTALLATION/COMMISSIONING...................................................................28
6.3.1 Transmitter Operating in 6 ByteOutput Mode...............................28

ii Smart Temperature Transmitter STT250 – Operator Manual
6.3.2 Transmitter Operating in 4 Byte Digital Output or in 4-20 mA
Analog Mode.................................................................................................28
6.3.3 Transmitter Operating in 4-20 mA Analog Output Mode..............28
6.4 DIAGNOSTIC AND TROUBLESHOOTING.........................................................29
6.4.1 Analog Meter.......................................................................................29
6.4.2 Smart Meter.........................................................................................29
6.4.3 4-20 mA Analog Mode Calibration of Smart Meter.....................30
APPENDIX A TRANSIENTPROTECTOR INSTALLATION
INSTRUCTION..............................................................................33
A.1 OVERVIEW ....................................................................................................33
A.2 FEATURES AND BENEFITS ............................................................................33
A.3 ELECTRICAL CHARACTERISTICS...................................................................33
A.4 INSTALLATION PROCEDURE.........................................................................34
A.5 WIRING REFERENCE....................................................................................35
FIGURES AND TABLES
Figure 1 : Operating Areas......................................................................................2
Figure 2: Bench Check Wiring Connections ........................................................7
Figure 3: Output Sensor Wiring Connections ......................................................8
Figure 4: Flow Chart for analog and DE Configuration..................................10
Figure 4-1: Specific Flow Chart for DE Configuration.....................................11
Figure 5: Flow Chart for HART Configuration...................................................13
Figure 6: DIN Rail Mounting................................................................................14
Figure 7: Wall Mounting Dimensions .................................................................15
Figure 8: Pipe Mounting Dimensions .................................................................15
Figure 9: Spring Loading and Sensor Assembly..............................................16
Figure 10: Aluminium Direct Head Mount Housing Dimensions....................17
Figure 11: Plastic Direct Head MountHousing Dimensions ..........................17
Figure 12: Cast Iron Direct Head Mount Housing Dimensions ......................17
Figure 13: Stainless Steel Direct Head Mount Housing Dimensions............18
Figure 14: Meters Connections ...........................................................................27
Figure 15: Horizontal Style Bargraph.................................................................29
Figure A-1: Typical wiring of transient protector to STT250 transmitter......35
Table A-1 Electrical Characteristics ...................................................................33
Table A- 2 Transient Protector Installation.......................................................34

Smart Temperature Transmitter STT250 – Operator Manual 1
1. OVERVIEW
1.1 Introduction
The STT250 Smart Temperature Transmitter is a microprocessor based unit suitable
for accepting a wide variety of thermocouple and resistance temperature detector
sensor inputs or direct ohm or milli-volt inputs and providing a 2 wire
4-20 mA “Analog”, digital “DE”, or analog “HART” proportional output.
The transmitter offers high accuracy and stability together with wide flexibility to suit a
wide range of applications. All adjustments and operational settings are implemented
through the Smart Field Communicator (DE) or the HART communicator (HART).
Both field communicators access the transmitter by connecting across the 4-20 mA
wiring in parallel with the STT250 anywhere along the wiring up to 1500 meters from
the transmitter for both the DE and HART protocol versions.
Note: 1500 m is the maximum HART cable length but may be restricted by cable
capacitance limits.
nModel STT25H provides the HART protocol output. The terminal assembly is
blue for visible differentiation.
nModel STT25M provides a 4-20mA analog output and is configurable with the
Honeywell Smart Field Communicator (SFC) or the PC based Smartline
Configuration Toolkit (SCT).
nModel STT25D provides both the 4-20mA analog output as in Model STT25M or
the digital DE protocol for digital integration to the Honeywell control system or
other compatible interfaces.
The STT250 is based on a rugged compact package with encapsulated electronics for
high reliability and includes facilities for spring loading of the sensor at a 33 mm
pitch in accordance with DIN 43729. The unit is available either for DIN rail mounting
or supplied in a variety of enclosures for direct sensor, pipe or wall mounting (See
Figures 6 through 13).
“HART is a Registered Trademark of HART Communication Foundation.”
“The STT3000 Smart Temperature Transmitters are manufactured under at least one
of the following patent numbers: 4.734.873, 4.592.002, 4.587.466, 4.553.104,
4.494.183”

2Smart Temperature Transmitter STT250 – Operator Manual
2. TECHNICAL SPECIFICATIONS
2.1 Environmental Conditions
Reference Rated
conditions
Operating limits Storage
Temperature 23°C 73°F -40°C to 85°C
-40°F to 185°F -40°C to 85°C -40°F to 185°F -50°C to 100°C -58°F to 212°F
Humidity
(%RH) 10 to 55 5 to 95 5 to 100 5 to 100
Supply
voltage 24 V /
250 Ω(See Figure 1)
Shock/
Vibration 40 g max 4 g max over
15-200 Hz (3 g
with meter)
CE MARK compliance:
In compliance with EMC directive 89/336/ECC:
- without shielded wires 10 V/m, 0.1% of Max span
- with shielded wires and mounted in metallic housing: 30 V/m,
0.1% of max span.
2.1.1 Physical Specifications
The STT250 is available in 3 physical variations to suit various application
requirements.
Loadresistance
(Ohms)
DE operating area
0
0
0
HART operating area
Supply
voltage
(Vdc)
1100
100
Load resistance
(Ohms)
10.8 13
operating communication area
35 V
Supply
voltage
(Vdc)
1100
250
10.8 16.3
operating communication area
35 V
operating area
with no
communication
0
operating area
with no
communication
Figure 1: Operating Areas

Smart Temperature Transmitter STT250 – Operator Manual 3
3. THEORY OF OPERATION
3.1 Basic Operation
As shown in Figure 2, the transmitter is powered via the 2 wire, 4-20 mA signal
connected to the + and - terminals on the output side of the module. Inputs are
sampled at a rate of 2 times per second and digitized by the A/D converter. Data is
then transferred across the galvanic isolation interface (both power supply and signal
interface of the A/D converter are galvanically isolated), compensated for cold
junction or resistance lead length. The process value is post read validated for
sensor wiring and signal integrity against reference values. Digital data is then
linearized and ranged to the lower and upper range values held in non volatile
memory and converted back to an analog signal. Any configuration changes are held
in non volatile memory so that they are secured against power failure. If a custom
configuration was not specified, the data programmed into the non volatile memory of
the unit at the manufacturing location is the default shipping data shown below.
Tag I.D. xxxxxxxx
Sensor type mV
Sensor fault detection ON
Latching Disabled
Line filter 50 Hz (Amiens) - 60 Hz (Phoenix)
Output type Linear
Write protect Disabled (1)
Password 0000
Damping 0 second
LRV (Lower Range Value) 0mV
URV (Upper Range Value) 45mV
Output mode Analog (DE or HART)
Digital DE conf. 6 byte/Single rng.-S V
The data can be configured in the field by connecting a Communicator across the 4-
20 mA wires or a PC. The fail-safe link between the + and - terminals determines
where the output will drive when the STT250 detects an open sensor input or internal
failure. The unit will drive upscale to 21.8 mA when the fail-safe link is in the U position
and downscale to 3.8 mA in the D position.
The output of the STT250 can be 4-20mA analog (DE or HART) or digital DE protocol.
The digital DE output is used primarily with Honeywell’s control system where it
improves performance by avoiding conversion to/from an analog signal and offers full
database integration of field transmitters with the central control system.
(1) To protect the integrity, write protect is software configurable and accessible
through a password. The fall-back password is an algorithm based on the unit serial
number. If the password is lost, contact your regional Technical Assistance Center
(TAC) with the unit serial number.

4Smart Temperature Transmitter STT250 – Operator Manual
3.2 Configuration Tools
3.2.1 Smart Field Communicator (SFC)
As previously indicated, the SFC communicates by connecting across the 4-20 mA
wiring. DE Communication is by 16 mA pulses which disturb the 4-20 mA output
signal. When in analog mode, ensure that receiving instruments are not on automatic
control. The SFC does not feed 16 mA pulses into the loop but instead merely uses
the power on the 4-20 mA wires and switches it through a field effect transistor output
switch. The SFC always acts as a master and the transmitter as a slave. When the
transmitter is operating in the digital DE mode, there is no wake-up pulse required and
the SFC communication does not disturb the PV signal. Consequently, there is no
need to put the loop on manual control when operating in the DE mode.
Supported Commands:
∗Read/write ID (e.g. TID 250)
∗Select a sensor type (e.g. Pt100)
∗Select linear/non linear reading (i.e. Linear for °C etc., Non linear for
Ωand V)
∗Enable/disable sensor break detection
∗Set damping time (e.g. 0 second)
∗Read URL (upper range limit), LRL (lower range limit) and span
∗Read process value and cold junction value in engineering units
∗Read output in % of span
∗Read STT250's software version
∗Read fail-safe direction configured by link
∗Set/reset user calibration to specific sensor
∗Set 0 and 100% output calibration
∗Force output current
∗Read/write scratch pad
∗Select broadcast type 4 or 6 bytes (Digital DE only). 6 bytes broadcasts PV and
transmitter database while 4 bytes broadcasts PV only
∗Enable/disable write protect
∗Select 50 Hz/60 Hz power line filter
∗Enable/disable latching. Latching means the alarm needs acknowledgment. Press
"STATUS" key to acknowledge the alarm.
If latching is disabled, the STT250 will leave the alarm mode as soon as the alarm
cause disappears.
3.2.2 HART Communicator (model 275)
The HART Communicator communicates by connecting across the 4-20 mA wiring.
Communication is by a high frequency carrier superimposed onto the 4-20 mA signal.
The HART transmitter transmits by modulating the 4-20 mA DC loop current with a 1
mA p-p AC current signal. This modulated signal does not disturb the output signal
(PV) since the average value of the communication signal is zero. Thus, it is
unnecessary to put the loop on manual control with Model STT25H.

Smart Temperature Transmitter STT250 – Operator Manual 5
Supported Commands:
∗Read/write ID
∗Select sensor type
∗Select units
∗Change units (linear / non-linear)
∗Set LRV and URV
∗Set damping time
∗Read URL and LRL
∗Read process value and cold junction value
∗Read output
∗Read STT250's software version
∗Read fail-safe direction
∗Set/reset user calibration
∗Set 0% and 100% output calibration
∗Read/write scratch pad
∗Force output current
∗Enable/disable sensor break detection
∗Enable/disable latching
∗Read/write multidrop address
3.2.3 Smartline Configuration Toolkit (SCT)
The SCT supports several Smartline products which use the DE protocol, including
the STT350, STT25M and STT25D. Since the STT25M and STT25D
configuration/data are a subset of the STT350, most functions are supported by the
current version of the SCT software. The only confusion which may occur is if you try
to configure the STT250 for functions which are available only with the STT350
transmitter, as shown below.
•Sensor types C, D, Ni/NiMo, Radiamatic, Pt500, Ni500, Cu10 and Cu25 are only
available with STT350.
•External cold junction compensation is only available with STT350.
•High/Low PV read is only available with STT350.
•SCT does not support HART protocol and should not be used with Model
STT25H.
•The STT25M cannot be changed from analog to digital DE mode.
To access to the new functionalities of the STT25M and STT25D, you need a
SCT3000 Version 154 or greater.
The procedure below outlines the steps to set the three new configuration options.
There are two methods to configure the STT25M and STT25D new functionalities,
both using the Generic Property Sheets.
•Method 1
Open the BLANK Generic Property Sheets called BLANK.GDT by selecting the "File -
New" menu which displays the "Add File Template". Select "Generic Templates" TAB
and BLANK.GDT file.

6Smart Temperature Transmitter STT250 – Operator Manual
INDEX DATA TYPE VALUE
To set the Input Latching to LATCHED 0UInt8 103
To set the Input Latching to NOT
LATCHED 0UInt8 102
To turn on the NAMUR configuration 8UInt8 1
To turn off the NAMUR configuration 8UInt8 0
To enable Write Protection 12 UInt8 255
To disable Write Protection 13 String XXXX
(Note 1)
ATTENTION: To change the PASSWORD 14 String XXXX
(Note 2)
(Note 3)
NOTES:
1. Enter the 4 character password.
2. Enter the NEW 4 character password in numeric or capital alpha characters.
3. PLEASE USE EXTREME CAUTION WHEN USING THIS INDEX. THE OLD
PASSWORD IS NOT VALIDATED BEFORE ENTERING THE NEW PASSWORD.
4. The fall-back password is an algorithm based on the unit serial number. If the
password is lost, contact your regional Technical Assistance Center (TAC) with
the serial number.
•Method 2:
Open one of the 6 Generic Property Sheets set up to configure each of the following:
1. Input Status Latching àOn
2. Input Status Latching àOff
3. "NAMUR" Configuration àOn
4. "NAMUR" Configuration àOff
5. Enable Database Write Protection
6. Disable Database Write Protection (via user entered password).
NOTE: Since no template is provided for changing the password, use the
BLANK.GDT file described in Method 1 to change the password.
Action Select the "File - New" menu which
displays the "Add File Template". Select
"Generic Templates" TAB and:
Input Status Latching àON LATCHED.GDT file
Input Status Latching àOFF NOTLATCH.GDT file
"NAMUR" Configuration àOn NAMON.GDT file
"NAMUR" Configuration àOff NAMOFF.GDT file
Enable Database Write Protection ENABWP.GDT file
Disable Database Write Protection DISABWP.GDT file
Once you select the template, download the template to the STT250.

Smart Temperature Transmitter STT250 – Operator Manual 7
4. BENCH CHECK INSTALLATION/COMMISSIONING
4.1 Unpacking
Unpack the unit and verify the contents are as ordered.
4.2 Equipment
If a bench check is intended, the equipment needed is:
üan input sensor suitable for the required application or an equivalent calibrator
which can simulate milli-volts, resistance temperature detector, thermocouple or
resistance (ohms) inputs,
üa nominal 24 Vdc power supply with less than 100 mV peak ripple and able to
supply at least 40 mA,
üa Smart Field Communicator (SFC) with STT25M or STT25D or HART
Communicator (model 275) with STT25H,
üconnection wiring and 250 ohms resistor,
üa Digital Voltmeter (DVM) with range covering 0-5 Vdc. If a high speed sampling
DVM is used, a 1 Hz (160 msec.) averaging filter is recommended.
NOTE: If you are going to check calibration using a thermocouple input, ensure
that the cold junction temperature is stabilized. After connecting and powering
up all equipment, including the transmitter, protect the transmitter from air
drafts and allow at least 1 hour before taking readings.
4.3 Installation
Connect the equipment as in Figures 2 and 3. For more detailed wiring drawings, refer
to drawings listed in Section 5.4.
ATTENTION: Do not connect power supply to sensor wiring terminals.
24 Vdc
Power supply
SFC
or
HART
communicator
4-20 mA
DVM
250 ohms
+-
+
-
Figure 2: Bench Check Wiring Connections

8Smart Temperature Transmitter STT250 – Operator Manual
RTD
2 wires RTD
or 2 wires ohm 3 wires RTD
or3wiresohm 4 wires RTD
or 4 wires ohm
RTD RTD
Single T/C and mV
White
White
Red
Red
White
Red
Red
White
Red
2wires 4 wires
Potentiometer wiring
3 wires
46188466-201
Figure 3: Output Sensor Wiring Connections
4.4 Grounding and Shielding Techniques
The current output signal will operate in either a floating or grounded system. If the
signal appears noisy or erratic, it is recommended to ground the loop at the negative
terminal of the power supply.
Shielding should only be connected to ground at one point to avoid ground loops.
4.5 STT250 Configuration
NOTE: If the transmitter is Model STT25D and configured for digital DE output,
the DVM will not display the output during the bench check. The output can be
changed to 4-20 mA analog for calibration checks. Remember to change the
mode back to digital DE at the completion of the check.
4.5.1 Analog Output Configuration (based on STS103)
1. Turn on the power supply and the SFC. On power up, the SFC will display "Self
Check" for a few seconds, verify proper operation and display "put loop in
manual".
2. Press ID button. The transmitter will respond with a display of its name, typically
"STT TagNo XXXXXXXX". "STT" cannot be changed since it identifies the type of
transmitter. The current name XXXXXXXX has a cursor under the first letter
showing that it can be changed to an 8 character alpha-numeric tag number by
using number and letter keys.

Smart Temperature Transmitter STT250 – Operator Manual 9
NOTE: Even though the transmitter is working properly, the SFC may display
"CRITICAL STATUS"and an error message when you press"STATUS".
The error messages are "INPUT OPEN""UNCERTAIN READING""I/P OUT OF
SPEC".
The "CRITICAL STATUS" message is caused by one of the following:
⇒You have not connected a sensor to the input.
⇒There is an open circuit in the sensor, connecting wiring or terminal connections.
⇒You have connected a T/C or other milli-volt source to the T/C terminals and the
transmitter is configured for RTD input (or vice versa).
3. Press "Status" to verify "Status Check = OK" is displayed.
4. Press "Conf" to access the transmitter database and configure it as required. As
mentioned earlier, the default shipping mode of engineering units is
0-45 mV input, mV range.
You can now customize the unit to your specific application. The flow chart in Figure 4
gives a simplified overview of selections and key strokes.
See SFC Operating Card 34-ST-11-16 for more details on Latching, NAMUR and
Write Protection functionalities.
In summary: - Press "Next" (or ) and "Prev" (or ) to scroll through the
different categories.
- Press "Menu Item" to access the possible selections of any
category: the èkey steps on to the next selection while the
çkey steps back to the previous selection.
Note that with the "Menu Item" key you can only move to the right.
5. When a desired configuration item appears on the SFC display, this item may be
configured in the SFC "Hold" memory by pressing "Enter".
When you have completed configuring all items accessible via the "STT Conf"
Key, or you try to exit via the "CLR" Key, the SFC will ask "Download Change?".
Press "Yes" (Enter) and the changes will be down-loaded from the SFC to the
transmitter, or press "No" (CLR) and the SFC hold memory will be erased.
6. Having now configured the input type etc., press "LRV" and key in the required
temperature for 4 mA output (e.g. 100°C [212°F]).
7. Press "Enter" to load this into the transmitter and repeat with "URV" for the 20 mA
output (e.g. 500°C [932°F]).
Note that if the input type is changed or the output type is changed from linear
to non-linear (or vice versa), the LRV and URV values will default to factory set
values and the unit selection (°C/°F) will default to°C.
Your STT250 is now configured for your applications.
You can check out the performance by varying the input and observing the output
response on the DVM.

10 Smart Temperature Transmitter STT250 – Operator Manual
Keys Shift
Keys Menu 1 Menu 2
ID
A
DE READ
CONF
BEnter
CHANGE
CONF
Enter
PROBE (J, K, etc...)
CJ Ext / Int
Line Filter
Next
Inp Fault Det
O/P Linear
LATCHING
CONFIG?
Enter
CHG LATCHING
CFG?
NAMUR
CONFIG?
Enter
CHG NAMUR
CFG *?
WRITE
PROTECT?
Enter
CHG WRITE PROT?
DAMP
C
UNITS
D
LRV
E
URV
F
SET
G
OUTPUT
J
CORRECT
K
PREV
L
-->
M
7
N
8
O
9
P
<--
Q
A <--> DE
4
R
5
S
6
T
STAT
U
F/S DIR
1
V
2
W
3
X
SW VER
SPAN
Y
URL
0
Z
.
→
SCR PAD
+/-
NUM / ALPHA
SHIFT
∧
CLR (NO)
ENTER (YES) NON-VOL
NEXT
H
MENU ITEM
I
RESET
INPUT
LRL
SER #
READ CJ
Figure 4: Flow Chart for analog and DE Configuration

Smart Temperature Transmitter STT250 – Operator Manual 11
4.5.2 DE Digital Output Configuration
The STT25D transmitter can operate in either an analog or a digital DE
communications mode. You can use the Smart Field Communicator (SFC) to set
transmitter operation mode as analog or digital DE communications. Note that
STT25D transmitters are factory set for analog communications operation.
This addendum outlines additional steps for the Configuration Flow Chart in
Figure 4-1 of this Operator Manual to configure parameters for DE communications
mode and change transmitter operation from analog to digital DE communications.
The DE configuration parameters are:
- Type of transmitter operation
- Message format
- Failsafe mode for the digital control system.
Use the following flow chart to supplement in Figure 4 to configure the DE mode
parameters and to set your STT25D for DE communications operation.
ADDITIONAL NOTE:
Not all failsafe mode selections apply for given type of transmitter operation.
Keys Shift Keys Menu 1 Menu 2
MENU ITEM IDE CONF Enter Typeof
transmitter
operation(single
range, dual range
STDC, single range
W/SV)
Message format
(W/O DB - 4 bytes
W/DB - 6 bytes)
Fail-safemode
(B/O Lo, B/O Hi,
LKG, FSO)
<-- Q A <--> DE Enter Change to DE? Enter Are you
sure? *
Figure 4-1 : Specific Flow Chart for DE Configuration
You cannot change to DE with a STT25M. If you attempt to do it, an “INVALID
REQUEST” message will appear.

12 Smart Temperature Transmitter STT250 – Operator Manual
Operating card (34-ST-11-16) included with the STS103 covers the smart transmitter
functions included in the STT250 (e.g. damping, calibration, output mode etc.). Since
the SFC is a universal configuration tool for a wide range of Honeywell transmitters,
some proposed menu items are not possible with the STT250, as listed in Section
3.2.3. In this case, the download will result in an “invalid request” response.
Additional configuration notes:
1. This series mode filter should match the local AC supply frequency. It is set to 60
Hz for United States and to 50 Hz for other countries.
2. Sensor fault detection "ON" will drive the output upscale or downscale as selected
in the event of an open input condition or in response to most electronic
malfunctions. Sensor fault detection "OFF" will give an indeterminate output with
an open input condition.
3. O/P linear will always read in degrees (C, F, R or K, as selected) for T/C and RTD
inputs. O/P non linear will read in milli-volts for T/C inputs and in ohms for RTD
inputs.
4.5.3 HART Configuration
1. Turn on the power supply and the HART Communicator.
2. On power up, the communicator will display "Self Test in Progess", verify proper
operation and display "STT250 Temp: xxxxxxxxxx" (xxxxxxxxxx represents the
tag) and "On-line".
The process value, output current, LRV and URV are displayed a few seconds
later.
NOTE: Even though the transmitter is working properly, the HART Communicator may
display "Sensor failure".
- Press "NEXT". "Sensor 1 failed" is displayed.
- Press "NEXT" again. "Ignore next 50 occurrences of status" is displayed.
- Confirm with "YES" to correct the problem.
The cause is probably one of the following:
⇒You have not connected a sensor to the input.
⇒There is an open circuit in the sensor, connecting wiring or terminal connections.
⇒You have connected a T/C or other milli-volt source to the T/C terminals and the
transmitter is configured for RTD input (or vice versa).
3. Press èto select "Devicesetup" menu.
4. Then use êto highlight the "Basic setup" followed by èto access the
transmitter database and configure it as required.
As mentioned earlier, the default shipping mode for units is 0-45mV input,
0-45 mV range.
You can now customize the unit to your specific application. The flow chart in Figure 5
gives a simplified overview of selections and key strokes.
In summary: - pressingèselects a menu,
- pressingéorêaccesses the selections of any
category,
- pressingçsteps back to the previous menu.

Smart Temperature Transmitter STT250 – Operator Manual 13
You can check out the performance by varying the input and observing the output
response on the DVM.
Additional note :
This series mode filter should match the local AC supply frequency.
PV
1 Process
PV % rnge
4mA
Variables
PVAO 20mA
SV Other
End
1 Device
Setup
Master Reset
2 PV
2 Diagnostics Loop Test
3 PV AO
& Services Calibration
4 PV LRV
D/A trim
5 PV URV Connect Reference Meter
Tag
3 Basic Setup
PV Snsr Unit
PV LRV
Enter values
PV URV
Device info
PV LRL
PV Damp
PV URL
SV Unit
Distributor
Model
Dev id
Tag
Write protect
Message
Sensor Name
Line filter
PV Damp
PV LRV
4 Detailed
PV URV
Setup
PV % range
Analog Output
HART Output
Model
Tag
Message
Dev id
Break detect
Latching alarm on/off
5 Review
Latch clear
Sensors
Signal Condition
Output Condition
Device Information
Alarm
Write protect
1
2
3
4
Sensor selection
Write protect
WP on/off
Change pwd
Apply values
Enter values
Correct input LRV
Correct input URV
Reset Corrects
1
2
3
4
5
1
2
3
4
5
6
1
2
3
4
5
6
1
2
3
4
5
1
2
3
4
1
2
3
4
5
1
2
1
2
3
4
1
2
3
4
1
2
3
4
5
6
7
1
2
3
4
1
2
3
1
2
3
4
Device status
1
2
3
4
5
PV
Alarm direction
Namur
Loop test
D/A trim
1
2
Poll addr
Num req preams
Alarm direction
Compensation
Universal revision
1
2
Software revision
Revisions
Universal revision
1
2
Software revision
Revisions
Figure 5: Flow Chart for HART Configuration

14 Smart Temperature Transmitter STT250 – Operator Manual
4.6 Mounting
4.6.1 DIN Rail Mounting
If the STT250 is to be installed on DIN Rail then the main considerations are electrical
connections and mechanical fixing. Electrical connections are identical to the bench
test instructions (see page 7) except that compensation cable is likely to be used with
thermocouples. Mechanical fixing of the module is by means of the snap-in DIN Rail
Clips which are screwed to the bottom lugs of the module.
INSTALLATION WITH "G" DIN
RAILRIGHTVIEW
INSTALLATION WITH TOP HAT/
" " DIN RAIL RIGHT VIEW
46188464-201
31
(1.22)
41.4
(1.63)
"G" DIN RAIL
TOP HAT/ " " DIN RAIL
PROTECTIVE CAP
44.4
(1.75)
Figure 6: DIN Rail Mounting
4.6.2 Mounting Module in Housing
The STT250 module can be installed in a variety of housings suitable for direct head
mounting, 2'' (50mm) pipe mounting or wall mounting.
Ensure that the installation location is suitable for reliable transmitter operation (e.g.
for high temperature applications, a thermowell extension is recommended to
minimize failure rates due to high ambient temperatures near the transmitter).

Smart Temperature Transmitter STT250 – Operator Manual 15
FIELD MOUNT HOUSING
WITHMETER
RIGHTVIEW
FIELD MOUNT HOUSING
WITHOUTMETER
RIGHT VIEW
FIELD MOUNT HOUSING
WITH OR WITHOUT
METER
FRONT VIEW
A
46188467-201
A
BB
142
(5.59)
40
(1.57)
59.5
(2.34)
60
(2.36)
94
(3.7)115
(4.53)
Figure 7: Wall Mounting Dimensions
FIELD MOUNT HOUSING WITH
OR WITHOUT METER (FRONTVIEW)
14,9
[0.59]
FIELD MOUNT HOUSING
WITH METER (RIGHT VIEW) FIELD MOUNT HOUSING WITHOUT METER
(RIGHTVIEW)
14,9
[0.59]
CLEARANCE FOR CAP
REMOVAL CLEARANCE FOR CAP
REMOVAL
A
B
A
B
142
[5.59]
40
[1.57]
191,5
[7.54]
60
[2.36]
61,8
[2.43]
39
[1.54]
94
[3.7]
115
[4.53]129,5
[5.1] 46188468-201
Figure 8: Pipe Mounting Dimensions
Dimensions Aluminium (field mount
housing) 316 Stainless Steel (field mounthousing)
A B A B
Without integral
meter 70 mm
[2.76 inch] 120,8 mm [4.76 inch] 95,5 mm [3.76 inch] 146,3 mm [5.76 inch]
With integral meter 127 mm
[5.00 inch] 210,8 mm [8.30 inch] 127 mm [5.00 inch] 210,8 mm [8.30 inch]

16 Smart Temperature Transmitter STT250 – Operator Manual
SCREWS M4
SPRINGS
FEED-THROUGH
HOLE FOR
SENSOR WIRES
STT250
SENSOR PLATE
ASSEMBLY
CIRCLIPS
46188463-201
33 mm
Figure 9: Spring Loading and Sensor Assembly
Spring loading is available worldwide with direct head mounting. In North America, the
spring loading is typically included in the sensor/thermowell assembly and is available
with all housings. For non-North American spring loading as shown in Figure 9, simply
include the springs under the 33 mm pitch mounting screws, pass the screws through
the module and sensor mounting plate and snap in the retaining circlip to the screws
to hold the assembly together. Guide the sensor assembly through the housing sensor
entry and screw down the 33 mm screws until the limit is reached as the sensor
presses against the bottom of thermowell.
For wall or 2'' pipe mounting, the temperature sensor can be remote from the STT250
field mount housing or integral to the housing. For remote installations, the sensor
wiring should be run in shielded, twisted pair wiring and connected via one of the
housing wiring entries. For explosionproof/flameproof installations, ensure that the
cable entries are fitted with flameproof adaptors and that the wiring grade complies
with local standards.
Note that for internal spring loading applications including flameproof requirements,
the direct head mount housing should be ordered with the sensor to incorporate the
flame trap. Then connect the sensor wiring to the appropriate input terminals. Ensure
that you have selected the desired failsafe link direction (up/down). Connect the
output 2 wire signal to power connections. Screened, twisted pair wiring is
recommended but not essential. The connection route to the receiving device may be
run in multicore cable without any cross talk concerns for either HART or DE protocol
units. However, ensure that no digital I/O signals co-exist in the same multicore as
HART protocol signals since these signals can cause interference. Galvanic isolation
of input/output circuits enables use with grounded or ungrounded probes. This
enables connection of the output signal to ground (e.g. at safety barriers), without
creating a ground loop.
Screw down the housing cover securely.

Smart Temperature Transmitter STT250 – Operator Manual 17
BB section AA section
(Dimensions in millimeters) 46188452-0XX
(33)
2 x M4
(40)
2 x M3
(41)
1/2" NPT
or M20
1/2" NPT
Figure 10: Aluminium Direct Head Mount Housing Dimensions
CC sectionBB section
46188455-0XX
2 x M4
(26.5)
(57)
AAsection
(33)
2 x M4
A
A
(85)
1/2"
NPT
1/2"
NPT or
M20
(57)
A
A
(26.5)
Figure 11: Plastic Direct Head Mount Housing Dimensions
AA sectionBB section
46188453 -0XX
1/2"
NPT or
M20
2 x M4
2 x M4
(111)
( 104)
1/2" NPT
33 mm
(41)
Figure 12: Cast Iron Direct Head Mount Housing Dimensions