Honeywell STT25D, STT25H, STT25M Operator's 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 Byte Output 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 TRANSIENT PROTECTOR 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 Mount Housing 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.
n Model STT25H provides the HART protocol output. The terminal assembly is
blue for visible differentiation.
n Model 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).
n Model 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”
2 Smart 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 sp an
- 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.
Load resistance
(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.
4 Smart 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
Ω and 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.
6 Smart Temperature Transmitter STT250 – Operator Manual
INDEX DATA TYPE VALUE
To set the Input Latching to LATCHED 0 UInt8 103
To set the Input Latching to NOT
LATCHED
0 UInt8 102
To turn on the NAMUR configuration 8 UInt8 1
To turn off the NAMUR configuration 8 UInt8 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 à On
2. Input Status Latching à Off
3. "NAMUR" Configuration à On
4. "NAMUR" Configuration à Off
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 à ON LATCHED.GDT file
Input Status Latching à OFF NOTLATCH.GDT file
"NAMUR" Configuration à On NAMON.GDT file
"NAMUR" Configuration à Off 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:
ü an input sensor suitable for the required application or an equivalent calibrator
which can simulate milli-volts, resistance temperature detector, thermocouple or
resistance (ohms) inputs,
ü a nominal 24 Vdc power supply with less than 100 mV peak ripple and able to
supply at least 40 mA,
ü a Smart Field Communicator (SFC) with STT25M or STT25D or HART
Communicator (model 275) with STT25H,
ü connection wiring and 250 ohms resistor,
ü a 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
8 Smart Temperature Transmitter STT250 – Operator Manual
RTD
2 wires RTD
or 2 wires ohm
3 wires RTD
or 3 wires ohm
4 wires RTD
or 4 wires ohm
RTD RTD
Single T/C and mV
White
White
Red
Red
White
Red
Red
White
Red
2 wires
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 è key steps on to the next selection while the
ç key 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.
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