Page 1
TRU100 MODEL 937
TEMPERATURE
REFERENCE
UNIT HANDBOOK
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
Isotech North America
158 Brentwood Drive, Unit 4
Colchester, VT 05446
Phone: (802)-863-8050
Fax: (802)-863-8125
www.isotechna.com
sales@isotechna.com
The company is always willing to give technical advice and assistance wh ere appropriate.
Equally, because of the programme of continual development and improvement we reserve the
Page 1 of 15
Page 2
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
right to amend or alter characteristics and design without prior notice. This publication is for
information only.
CONTENTS
DESCRIPTION PAGE NO:
Guarantee
CE Information
Health & Safety 6
Thermocouple Referencing
Outline Description
Temperature Control
Installation 10
Supply & Alarm Wiring
Maintenance
Panel & Layout Function 13
TRU 100 Spares Parts List
3
4 - 5
7
8
9
11
12
14
Page 2 of 15
Page 3
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
GUARANTEE
This instrument has been manufactured to exacting standards and is guaranteed for twelve
months against electrical break-down or mechanical failure caused through defective material
or workmanship. Failure caused by misuse is not covered. In the event of failure covered by
this guarantee, the instrument must be returned, carriage paid, to the supplier for examination,
and will be replaced or repaired at our option.
FRAGILE CERAMIC AND/OR GLASS PARTS ARE NOT COVERED BY THIS GUARANTEE
INTERFERENCE WITH, OR FAILURE PROPERLY TO MAINTAIN THIS INSTRUMENT MAY
INVALIDATE THIS GUARANTEE
RECOMMENDATION
The life of your ISOTECH instrument will be prolonged if regular maintenance and cleaning to
remove general dust and debris is carried out.
We recommend this instrument to be re-calibrated annually.
Serial No:........................................
Date:...............................................
Isotech North America
158 Brentwood Drive, Unit 4
Colchester, VT 05446
Phone: (802)-863-8050
Fax: (802)-863-8125
www.isotechna.com
sales@isotechna.com
Page 3 of 15
Page 4
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
EMC INFORMATION
This product meets the requirements of the European Directive on Electromagnetic Compatibility
(EMC) 89/336/EEC as amended b y EC Di rective 92/31/EEC and the European Low Voltage
Directive 73/25/EEC, amended by 93/68/EEC. To ensure emission compliance please ensure that
any serial communications connecting leads (RS232 or RS422(485)) are fully
screened.
The product meets the susceptibility requirements of EN 50082-1, criterion B.
Symbol Identification
ISO3864
Caution
( R
e f
er to Handbook)
IEC 417 Caution, Hot Surface
Publication Description
ELECTRICAL SAFETY
This equipment must be correctly earthed.
This equipment is a Class 1 Appliance. A protective earth is used to ensure the conductive parts
can not become live in the event of a failure of the insulation.
Page 4 of 15
Page 5
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
The protective conductor of the flexible mains cable which is coloured green/yellow MUST be
connected to a suitable earth.
The blue conductor should be connected to Neutral and the Brown conductor to Live (Line).
Warning: Internal mains voltage hazard. Do not remove the panels.
There are no user serviceable parts inside. Contact your nearest Isotech agent for repair.
Voltage transients on the supply must not exceed 2.5kV.
Conductive pollution, eg. Carbon dust, must be excluded from the apparatus. EN61010 pollution
degree 2.
The apparatus has two input connectors for temperature sensors, see Figure 1. The se i nputs
are only suitable for either a thermocouple or resistance thermometer. No other sensor or signal
may be connected.
ENVIRONMENTAL RATINGS
Operating Temperature
Relative Humidity
0-50°C
5-95%, non condensing
Page 5 of 15
Page 6
HEALTH AND SAFETY INSTRUCTIONS
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
1.
2. Wear appropriate protective clothing.
3.
4.
5.
6. Do not drill, modify or otherwise change the shape of the apparatus.
7.
8.
9. If cased, do not return the apparatus to its carrying case until the unit has cooled.
Read all of this handbook before use.
Operators of this equipment should be adequately trained in the handling of hot and cold
items and liquids.
Do not use the app a ra tus for jobs other than those for which it was designed, ie. the
calibration of thermometers.
Do not handle the apparatus when it has hot (or cold), un l ess wearing the appropriate
protective clothing and having the necessary training.
Do not dismantle the apparatus.
Do not use the apparatus outside its recommended temperature range.
10.
11.
There are no user serviceable parts inside. Contact your nearest Isotech agent for
repair.
Ensure mat erials, especially flammable materials are kept away from hot parts of the
apparatus, to prevent fire risk.
Page 6 of 15
Page 7
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
THERMOCOUPLE REFERENCING
It cannot be emphasised too strongly that thermocouple o utp uts are dependent upon emfs
generated by temperature differentials along individual conductors and not upon the presence
of junctions in the circuitry. However, access to an emf of this type, for measurement purposes,
requires the connection of additional conductors, and these ineluctably introduce th eir own
characteristic thermo-emfs into the circuit. The resultant nett emf will be the algebraic sum of
the individual emfs corre sponding to the respective temperatures of the end-points of each
conductor, i.e., of the junctions present in the measuring circuit. Indeed, it is this principle that
governs the practical application of thermocouples, although it should be noted that nett emfs are
functions of actual temperatures and are not uniquely det ermined by temperature differences.
In o the r words, the Seebeck coefficient (which is defined as the emf generated per unit
temperature difference) for a given material is, itself, a function of temperature and, moreover,
the uniqueness of its value at any given temperature is conditional upon physical and chemical
homogeneity of that material.
For practicability as a measuring device, the principal implication for a thermocouple is that it must
contain two junctions, one (the measuring junction) held at the temperature required to be
determined and the other (the referenc e junction) maintained at a known (reference)
temp e rature. Connections to the terminals of a measuring instrument potentially constitute
thermocouple junctions and care must be taken in arranging circuitry to eliminate their contribution
or to compensate for any influences thereby introduced. Qualitative acknowledgement, from a
thermoelectric point of view, of the presence of every element in a composite circuit has led to
a variety of arrangements to eliminate unwanted components of emf from thermocouple
measurements. However, the practical necessity remai ns of providing some means of
temperature referencing.
Some instruments involve the use of their terminals as reference junctions, for application with
a specified type of thermocouple that possesses one other junction only (th e m ea suring
junction). Such instruments usually incorporate a fa ci l ity for (electronic) "cold junction
compensation", thus indicating an emf relative to 0°C or, possibly, a direct reading of
temperature. However, a f undamentally more satisfactory procedure is to form reference
junctions using the conductors themselves and to employ an isothermal environment at a known
temperature (typically 0°C) into which the se junctions can be immersed. Several Isotech
products are dedicated to the provision of such environments; it is interesting to note, also, the
application of another thermoelectric phenomen on, Peltier cooling, to establish the working
conditions of those Isotech units designed to provide a reference temperature of 0°C.
Page 7 of 15
Page 8
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
Page 8 of 15
Page 9
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
OUTLINE DESCRIPTION
The TRU 100 unit is intended to produce a 0°C reference temperature environment that is
sufficiently accurate and stable for thermocouple applications.
It is a self-contained unit, housing a calibration environment in the form of a metal block cooled
by Peltier re fri geration modules controlled by solid-state circuitry, thus providing essentially
maintenance-free operation. Heat sinks and fan-cooling are incorporated in the assembly.
A feature of the TRU 100 is its rapid rate of cooling; a stable working temperature can normally
be attained within a period of ten minutes of switching on. The unit is very tolerant of high
ambient temperatures.
Two models are available. They differ when the number of thermocouples to be referenced is
more than 50 double junctions. Above 50 both sides ha ve an isothermal enclosure fitted to
accommodate the additional connectors.
Page 9 of 15
Page 10
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
TEMPERATURE CONTROL
Set in the underside of the block is a platinum resistance thermometer (PRT), which is used to
control the cooling function.
A Eurotherm 2216 PID Controller is used to give excellent stability and accuracy at the desired
temperature.
Page 10 of 15
Page 11
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
INSTALLATION
The thermocouple connections will be found by unscrewing a retentive screw on the side panel
(s) and opening the isothermal enclosure.
The top section of the klippon connectors have the wires for the reference thermocouples. Each
klippon is identified by a number and its polarity for both the thermocouple inputs and copper wire
outputs.
The top rows of the klippons are the inputs and the bottom rows are the outputs. When viewing
the klippons and the numbers 1, 2 etc. appear for the second time, these are the corresponding
copper outputs to the thermocouple inputs.
Termination should be with the correct sized screwdriver to avoid damage to the connectors.
Once all wires have been terminated secure the side panel (s).
Page 11 of 15
Page 12
SUPPLY AND ALARM WIRING
The colour convention for the mains-supply cable is:
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
LIVE
NEUTRAL - BLUE
EARTH - YELLOW AND GREEN
An Amphenol 7-pin circular socket is provided to facilitate connection to an al a rm system, if
desired, to signal out-of-temperature or power failure conditions.
The alarm leads have two wires on cool down or heat up, the alarm will switch for as long as
the T RU has deviated more than ±0.2°C of it’s set temperature.
- BROWN
ALARM WIRING
Page 12 of 15
Page 13
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
MAINTENANCE
Units intended for use in dusty environments can be equipped with a fan filter for the purpose
of keeping the heat-sink surfaces clean, thus maintaining efficiency of heat dissipation.
Other than changing the fan filter (if fitted), no maintenance is normally required.
Page 13 of 15
Page 14
PANEL AND LAYOUT FUNCTION
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
1.
2. Alarm Cable Socket
3.
4.
5. Cooling ducts and heat sink fins
6.
7.
Controller
Switched mains-cable socket and fuse holder
Metal block with pockets for thermocouple junctions
Isothermal probe enclosure
Isothermal enclosure for thermocouples
Page 14 of 15
Page 15
TRU 100 SPARE PARTS LIST
DESCRIPTION PART NUMBER
Controller 935-01-101B
TRU 100 HANDBOOK
MODEL 937
ISSUE 01 11/00
Block Assembly
P.R.T
Mains Transformer 935-19-29
Capacitor
Bridge Rectifier
Power Transistor 935-24-01
Switch Mains Plug & Fuse Holder 935-15-17
Alarm Socket
Fan 110V
Fan 240V 935-17-35
Fan Guard
940-02-00
935-14-33
935-04-01
935-38-08
935-16-40
935-17-31
935-17-18A
Fan Filter
Fuse 1.6A (T) 935-12-13
Page 15 of 15
935-17-32
Loading...