SMAR TT302 Manual

TT302ME

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Index
III
Table of Contents
INSTALLATION...........................................................................................1.1
GENERAL.................................................................................................................................1.1
MOUNTING..............................................................................................................................1.1
NETWORKWIRING..................................................................................................................1.2
BUS TOPOLOGY AND NETWORK CONFIGURATION .............................................................1.4
OPERATION................................................................................................2.1
FUNCTIONAL DESCRIPTION – HARDWARE...........................................................................2.1
TEMPERATURE SENSOR........................................................................................................2.3
CONFIGURATION.......................................................................................3.1
TRANDUCER BLOCK...............................................................................................................3.1
HOW CONFIGURE A TRANSDUCER BLOCK...........................................................................3.1
SENSOR TRANSDUCER NUMBER..........................................................................................3.1
SENSOR WIRING.....................................................................................................................3.1
JUMPER CONFIGURATION.....................................................................................................3.3
SENSOR CONFIGURATION ....................................................................................................3.3
HOW TO CONNECT TWO SENSORS TO TT302......................................................................3.5
COMPENSATION OF LEAD RESISTANCE FOR RTD or Ohm...................................................3.5
COMPENSATION OF LEAD RESISTANCE FOR RTD or Ohm Double Sensors.........................3.6
CALIBRATION IN TT302 BY THE USER...................................................................................3.6
CHANGING UNITS IN TEMPERATURE SENSORS...................................................................3.7
TRANSDUCER DISPLAY – CONFIGURATION..........................................................................3.7
DISPLAY TRANSDUCER BLOCK .............................................................................................3.8
DEFINITION OF PARAMETERS AND VALUES.........................................................................3.9
PROGRAMMING USING LOCAL ADJUSTMENT.....................................................................3.12
J1 JUMPER CONNECTIONS..................................................................................................3.13
W1 JUMPER CONNECTIONS.................................................................................................3.13
LOCAL PROGRAMMING TREE..............................................................................................3.14
MAINTENANCE PROCEDURES ................................................................4.1
TOUBLESHOOUTING...............................................................................................................4.1
DISASSEMBLY PROCEDURE..................................................................................................4.2
REASSEMBLY PROCEDURE...................................................................................................4.2
INTERCHANGEABILITY ...........................................................................................................4.3
RETURNING MATERIALS........................................................................................................4.3
TECHNICAL CHARACTERISTICS..............................................................5.1
FUNCIONAL SPECIFICATIONS................................................................................................5.1
PERFORMANCE SPECIFICATIONS.........................................................................................5.1
PHYSICAL SPECIFICATIONS...................................................................................................5.2
APPENDIX................................................................................................................................5.4

TT302 – Fieldbus Temperature Transmitter
IV

Introduction
V
Introduction
The TT302 is from the first generation of FIELDBUS devices. It is a transmitter mainly
intended for measurement of temperature using RTDs or thermocouples, but can also accept
other sensors with resistance or mV output such as: pyrometers, load cells, resistance position
indicators, etc. The digital technology used in the TT302 enables a single model to accept
several types of sensors, an easy interface between the field and the control room and several
others features that considerably reduces the installation, operation and maintenance costs.
FIELDBUS is not only a replacement for 4-20 mA or intelligent/smart transmitter protocols. It
contains much more. FIELDBUS is a complete system enabling distribution of the control
function to equipment in the field.
Some advantages of bi-directional digital communications are known from existing smart
transmitter protocols: higher accuracy, multivariable access, remote configuration and
diagnostics and multi-dropping of several devices on a single pair of wires. These protocols
were not intended to transfer control data, but maintain information. Therefore they were slow
and not efficient enough to be used.
The main requirements for Fieldbus were to overcome these problems. Closed loop control
with performance like a 4-20 mA system requires higher speed. Since higher speed means
higher power consumption, this clashes with the need for intrinsic safety. Therefore a
moderately high communication speed was selected, and the system was designed to have
minimum communication overhead. Using scheduling, the system controls the variable
sampling, the algorithm execution and the communication to optimize the usage of the
network, thus achieving high closed loop performance.
Using Fieldbus technology, with its capability to interconnect several devices, very large
control schemes can be constructed. In order to be user friendly, the function block concept
was introduced (users of SMAR CD600 should be familiar with this, since it was implemented
several years ago). The user may now easily build and overview complex control strategies.
Another advantage is adding flexibility, the control strategy may be edited without having to
rewire or change any hardware.
Now, thanks to Fieldbus, the transmitter accepts two channels, i.e., two measurements. This
reduces the cost per channel. Other function blocks are also available. They allow flexibility in
control strategy implementation.
The need for Fieldbus implementation in small as well as large systems was considered when
developing the entire 302 line of Fieldbus devices. They have the common features of being
able to act as a master on the network.
Get the best result of the TT302 by carefully reading these instructions.

TT302 – Fieldbus Temperature Transmitter
VI
WARNING
This Manual is compatible with version 3.XX, where 3 denote
software version and XX software release. The indication 3.XX
means that this manual is compatible with any release of
software version 3.

Section 1
1.1
Installation
General
The overall accuracy of temperature and other measurements depends on several variables.
Although the transmitter has an outstanding performance, proper installation is essential in order to
maximize its performance.
Among all factors which may affect transmitter accuracy, environmental conditions are the most
difficult to control. There are, however, ways of reducing the effects of temperature, humidity and
vibration.
Locating the transmitter in areas protected from extreme environmental changes can minimize
temperature fluctuation effects.
In warm environments, the transmitter should be installed in such a way as to avoid, as much as
possible, direct exposure to the sun. Installation close to lines and vessels subjected to high
temperatures should also be avoided. For temperature measurements, sensors with cooling-neck
can be used or the sensor can be mounted separately from the transmitter housing.
Use of sunshades or heat shields to protect the transmitter from external heat sources should be
considered.
Humidity is fatal for electronic circuits. In areas subjected to high relative humidity, the O-rings for
the electronic housing covers must be correctly placed and the covers must be completely closed by
tightening them by hand until you feel the O-rings being compressed. Do not use tools to close the
covers. Removal of the electronics cover in the field should be reduced to the minimum necessary,
since each time it is removed, the circuits are exposed to humidity. The electronic circuit is protected
by a humidity proof coating, but frequent exposure to humidity may affect the protection provided. It
is also important to keep the covers tightened in place. Every time they are removed, the threads
are exposed to corrosion, as painting cannot protect these parts. Code-approved sealing methods
should be employed on conduit entering the transmitter.
Connecting the sensor as close to the transmitter as possible and using proper wires (See Section 2
Operation), can decrease measurement error.
Mounting
The transmitter may be mounted in two basic ways:
Separated from the sensor, using optional mounting brackets.
Mounted on the sensor assembly.
It can be mounted in several different positions using the bracket, as shown in Figure 1.3 -
Dimensional Drawing and Mounting Positions. You can also see in the Figure 1.3 how the
conduit inlets for electrical connection are used to mount the sensor integral to the
temperature transmitter.
For better visibility, the digital display may be rotated in steps of 90º. (See Figure 4.1 – Four
Possible Positions of the Display).

TT302 - Fieldbus Temperature Transmitter
1.2
Network Wiring
Access the terminal block by removing the Electrical Connection Cover. This cover can be locked
closed by the cover locking screw (See Figure 1.1 - Cover Locking).To release the cover, rotate the
locking screw clockwise.
Figure 1.1 - Cover Locking
Cable access to wiring connections are obtained by one of the two conduit outlets. Conduit threads
should be sealed by means of code-approved sealing methods. The unused outlet connection
should be plugged accordingly.
The wiring block has screws on which fork or ring type terminals can be fastened. (See
Figure 1.2 - Ground Terminals).
Figure 1.2 - Ground Terminals
For convenience, there are three ground terminals: one inside the cover and two externally, located
close to the conduit entries.
WARNING
Do not connect the Fieldbus network wires to the sensor
terminals. (Terminals 1, 2, 3 and 4).

Installation
1.3
Figure 1.3 - Dimensional Drawing and Mounting Positions
The TT302 uses the 31.25-kbit/s voltage mode option for the physical signaling. All other devices on
the same bus must use the same signaling. All devices are connected in parallel along the same
pair of wires.
Various types of Fieldbus devices may be connected on the same bus. The TT302 is powered via
the bus. The limit for such devices is 16 for one bus for non-intrinsically safe requirement.
In hazardous areas, the number of devices may be limited to 6 devices by intrinsically safe
restrictions.
The TT302 is protected against reverse polarity, and can withstand ±35 VDC without damage.
Use of twisted pair cables is recommended. It is also recommended to ground shield of shielded
cables at one end only. The non-grounded end must be carefully isolated.
NOTE
Please refer to the General Installation, Operation and Maintenance
Manual for more details.

TT302 - Fieldbus Temperature Transmitter
1.4
Bus Topology and Network Configuration
Special requirements are applied to the terminator when used in a safety bus.
When intrinsic safety is required, a barrier should be inserted on the trunk between the power supply
and the terminator.
The barrier’s impedance should be greater than 460 Ωat 7.8 to 39 kHz.
The capacitance measured on both ends should not have a difference greater than 250pF from
each other.
The DF47 is recommended.
WARNING
HAZARDOUS AREAS
In hazardous areas with explosion proof requirements, the covers must be tightened with at least 8 turns. In
order to avoid the penetration moisture or corrosive gases, tighten the O’ring until feeling it touching the
housing. Then, tighten more 1/3 turn (120°) to guarantee the sealing. Lock the covers using the locking
screw.
In hazardous zones with intrinsically safe or non-incendive requirements, the circuit entity parameters and
applicable installation procedures must be observed.
Cable access to wiring connections is obtained by the two conduit outlets. Conduit threads should be sealed
by means of code-approved sealing methods. The unused outlet connection should be plugged and sealed
accordingly.
Should other certifications be necessary, refer to the certification or specific standard for installation
limitations.
The connection of couplers should be kept at less than 15 per 250 m.
Figure 1.4 - Bus Topology
CORRECT
WIRES
INCORRECT

Installation
1.5
Figure 1.5 - Bus Topology
Figure 1.6 - Bus Topology
Spur
Terminato
r
Spur
Spur
Shield
Junction
Box
Terminator
Enabled
++
+
PS302
FAIL
smar
ON
PSI302
FAIL 1
FAIL 2
FAIL 3
FAIL 4
smar
ON
smar
FUSE
2,5A
PSI3023.0(PowerSupplyImpedance)
1A
2A
3A
4A
IN
24VDC
BT
OUT 1
FieldbusH1
OUT 2
FieldbusH1
OUT 3
FieldbusH1
OUT 4
FieldbusH1
5A
6A
7A
8A
9A
10A
Coupler
++
+
+
Terminator
Enabled
Junction
Box
smar
PS302
FAIL
smar
ON
PSI302
FAIL 1
FAIL 2
FAIL 3
FAIL 4
smar
ON
FUSE
2,5A
PSI3023.0(PowerSupplyImpedance)
1A
2A
3A
4A
IN
24VDC
BT
OUT 1
FieldbusH1
OUT 2
FieldbusH1
OUT 3
FieldbusH1
OUT 4
FieldbusH1
5A
6A
7A
8A
9A
10A

TT302 - Fieldbus Temperature Transmitter
1.6

Section 2
2.1
Operation
The TT302 accepts signals from mV generators such as thermocouples or resistive sensors such as
RTDs. The criterion is that the signal is within the range of the input. For mV, the range is -50 to 500
mV and for resistance, 0-2000 Ohm.
Functional Description – Hardware
The function of each block is described below.
Figure 2.1 - TT302 Block Diagram
MUX Multiplexer
The MUX multiplexes the sensor terminals to the signal conditioning section ensuring that the
voltages are measured between the correct terminals.
Signal Conditioner
Its function is to apply the correct gain to theinput signals to make them suit the A/D - converter.
A/D Converter
The A/D converts the input signal to a digital format for the CPU.
Signal Isolation
Its function is to isolate the control and data signal between the input and the CPU.
(CPU) Central Processing Unit, RAM, PROM and EEPROM
The CPU is the intelligent portion of the transmitter, being responsible for the management and
operation of measurement, block execution, self-diagnostics and communication. The program is
stored in a PROM. For temporary storage of data there is a RAM. The data in the RAM is lost if the
power is switched off. However there is a nonvolatile EEPROM where data that must be retained is
stored. Examples, of such data are trim, calibration, block configuration and identification data.

TT302 - Fieldbus Temperature Transmitter
2.2
Communication Controller
It monitors line activity, modulates and demodulates communication signals and inserts and deletes
start and end delimiters.
Power Supply
Takes power of the loop-line to power the transmitter circuitry.
Power Isolation
Just like the signals to and from the input section, the power to the input section must be isolated.
Isolation is achieved by converting the DC supply into a high frequency AC supply and galvanically
separating it using a transformer.
Display Controller
Receives data from the CPU informing which segments of the Liquid Crystal Display, should be
turned on.
Local Adjustment
There are two switches that are magnetically activated. They can be activated by the magnetic tool
without mechanical or electrical contact.
Figure 2.2 - LCD Indicator

Operation
2.3
Temperature Sensors
The TT302, as previously explained, accepts several types of sensors. The TT302 is specially
designed for temperature measurement using thermocouples or Resistive Temperature Detectors
(RTDs).
Some basic concepts about these sensors are presented below.
Thermocouples
Thermocouples are constructed with two wires made from different metals or alloys joined at one
end, called measuring junction or "hot junction". The measuring junction should be placed at the
point of measurement. The other end of the thermocouple is open and connected to the temperature
transmitter. This point is called reference junction or cold junction.
For most applications, the Seebeck effect is sufficient to explain thermocouple behavior as
following:
How the Thermocouple Works (Seebeck Effect)
When there is a temperature difference along a metal wire, a small electric potential, unique to every
alloy, will occur. This phenomenon is called Seebeck effect. When two wires of dissimilar metals are
joined at one end, and left open at the other, a temperature difference between the two ends will
result in a voltage since the potentials generated by the dissimilar materials are different and do not
cancel each other out. Now, two important things must be noted. First: the voltage generated by the
thermocouple is proportional to the difference between the measuring-junction and the cold junction
temperatures. Therefore the temperature at the reference junction must be added to the
temperature derived from the thermocouple output, in order to find the temperature measured. This
is called cold junction compensation, and is done automatically by the TT302, which has a
temperature sensor at the sensor terminals for this purpose. Secondly, if the thermocouple wires are
not used, all the way to the terminals of the transmitter (e.g., copper wire is used from sensor-head
or marshaling box) will form new junctions with additional Seebeck effects. It will be created and ruin
the measurement in most cases, since the cold-junction compensation will be done at the wrong
point.
NOTE
Use thermocouple wires or appropriate extension wires all the way
from sensor to transmitter.
The relation between the measuring junction temperature and the generated mili-voltage is
tabulated in thermocouple calibration tables for standardized thermocouple types, the reference
temperature being 0 ºC.
Standardized thermocouples that are commercially used, whose tables are stored in the memory of
the TT302, are the following:
NBS (B, E, J, K, N, R, S & T)
DIN (L & U)
Resistive Temperature Detectors (RTDs)
Resistance Temperature Detectors, most commonly known as RTD’s, are based on the principle
that the resistance of metal increases as its temperature increases.
Standardized RTDs, whose tables are stored in the memory of the TT302, are the following:
JIS [1604-81] (Pt50 & Pt100)
IEC, DIN, JIS [1604-89] (Pt50, Pt100 & Pt500)
GE (Cu10)
DIN (Ni120)
For correct measurement of RTD temperature, it is necessary to eliminate the effect of the
resistance of the wires connecting the sensor to the measuring circuit. In some industrial
applications, these wires may be hundreds of meters long. This is particularly important at locations
where the ambient temperature changes constantly.

TT302 - Fieldbus Temperature Transmitter
2.4
The TT302 permits a 2-wire connection that may cause measuring errors, depending on the length
of connection wires and on the temperature to which they are exposed. (See Figure 2.3 - Two-Wire
Connection).
In a 2-wire connection, the voltage V2 is proportional to the RTD resistance plus the resistance of
the wires.
V2 = [RTD + 2 x R] x I
Figure 2.3 - Two-Wire Connection
In order to avoid the resistance effect of the connection wires, it is recommended to use a 3-wire
connection (See Figure 2.4 – Three-Wire Connection) or a 4-wire connection (See Figure 2.5 - Four
- Wire Connection).
In a 3-wire connection, terminal 3 is a high impedance input. Thus, no current flows through that
wire and no voltage drop is caused. The voltage V2-V1 is independent of the wire resistances since
they will be cancelled, and is directly proportional to the RTD resistance alone.
V2-V1 = [RTD + R] x I - R x I = RTD x I
Figure 2.4 - Three – Wire Connection
R
V2
TRANSMITTER
2,1
3,4 R
RT
D
I
R
V2
V1
TRANSMITTER
2,1
4
3
R
RT
D
I

Operation
2.5
In a 4-wire connection, terminals 2 and 3 are high impedance inputs. Thus, no current flows through
those wires and no voltage drop is caused. The resistance of the other two wires is not of interest,
since there is no measurement registered on them. Hence the voltage V2 is directly proportional to
the RTD resistance.
(V2 = RTD x I)
Figure 2.5 - Four - Wire Connection
A differential or dual channel connection is similar to the two-wire connection and gives the same
problem (See Figure 2.6 - Differential or Dual Connection). The resistance of the wires will be
measured and do not cancel each other out in a temperature measurement, since linearization will
affect them differently.
Figure 2.6 - Differential or Dual Connection
R
V2
2
1
+
-
3
4
R
RT
D
TRANSMITTER
I
R
R
V2
V1
1,3
2
4R
RTD1
RTD2
TRANSMITTER
I
I

TT302 - Fieldbus Temperature Transmitter
2.6

Section 3
3.1
Configuration
One of the many advantages of Fieldbus is that device configuration is independent of the
configurator. The TT302 may be configured by a third party terminal or console operator. Any
particular configurator is therefore not addressed here.
The TT302 contains two input transducer blocks, one resource block, one display transducer block
and other function blocks.
For explanation and details of function blocks, see the “Function Blocks Manual”.
Transducer Block
Transducer block insulates function blocks from the specific I/O hardware (sensors and actuators).
The transducer block controls the access to I/O through manufacturer specific implementation. This
allows the transducer block to be executed as frequently as necessary to obtain good data from
sensors without burdening the function blocks that uses the data. It also insulates the function
blocks from the manufacturer specific characteristics of certain hardware.
By accessing the hardware, the transducer block can get data from the I/O or pass control data to it.
The connection between Transducer block and Function block is called channel. These blocks can
exchange data through the interface.
Normally, transducer blocks perform functions, such as linearization, characterization, temperature
compensation and control of data exchange with the hardware.
How to Configure a Transducer Block
The transducer block has an algorithm, a set of contained parameters (it means you are not able to
link these parameters to other blocks or publish the link via communication), and a channel
connecting it to a function block.
The algorithm describes the behavior of the transducer as a data transfer function between the I/O
hardware and other function block. The set of contained parameters defines the user interface to the
transducer block. They can be divided into Standard and Manufacturer Specific.
The standard parameters are defined specifically to each device class such as, pressure,
temperature, etc., no matter is the manufacturer. Oppositely, the manufacturers specific are only
defined by the manufacturer. As common manufacturer specific parameters, we have calibration
settings, material information, linearization curve, etc.
When you perform a standard routine such as calibration, you are conducted step by step by a
method. The method is generally defined as guideline to help the user make common tasks.
SYSCON identifies each method associated to the parameters and enables the interface to it.
Sensor Transducer Number
The Sensor Transducer Number associates the sensor to the transducer. It can be set from one up
to two, in case of dual sensor.
Sensor Wiring
The TT302 accepts up to two sensors and may operate in one of four modes:
Single channel single sensor measurement
Dual channel dual sensor measurement
Single channel dual sensor differential measurement.
Single channel dual sensor backup measurement.

TT302 - Fieldbus Temperature Transmitter
3.2
When the sensor is dual, the sensor connected between terminals 3 and 4 is associated with the
first transducer, and the sensor connected between terminals 2 and 4 is associated with the second
transducer.
NOTE
Avoid routing sensor wiring close to power cables or switching equipment.
In accordance with connection and sensor types, the terminal blocks shall be wired as shown in
figure below (See Figure 3.1 - Sensor Wiring).
2 - WIRE RTD OR OHM INPUT
4 - WIRE RTD OR OHM INPUT
DUAL OR DIFFERENTIAL
RTD OR OHM INPUT DUAL OR DIFFERENTIAL THERMOCOUPLE OR
MILLIVOLT INPUT
THERMOCOUPLE
INPUT MILLIVOLT INPUT
3 - WIRE RTD OR OHM INPUT
1234
1234 1234 1234
1234
1234
12
DUAL OR DIFFERENCTIAL
RTD AND TC INPUT
341234
10 M Ω
DUAL OR DIFFERENTIA
L
RTD AND T
C
INP
U
T
++
12
10 M Ω
34
+
+
++
Figure 3.1 - Sensor Wiring