Isotech 944 Operating Manual
TRUE SURFACE TEMPERATURE
MEASUREMENT SYSTEM
MODEL 944
TTI 4 HANDBOOK
MODEL 944
ISS.04 - 06/06
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 ad vi ce and assistance where appropriate.
Equally, because of the programme of continual development and improvement we reserve the
right to amend or alter characteristics and design without prior notice. This publication is for
information only.
Page 1 of 32
TTI 4 HANDBOOK
MODEL 944
ISS.04 - 06/06
Page 2 of 32
CONTENTS
TTI 4 HANDBOOK
MODEL 944
ISS.04 - 06/06
Page No.
EMC Information
Health & Safety Instructions
Guarantee 5
Safety Precautions
Introduction
Technical Notes 7 - 13
TTI 4 System
Front & Rear View - Figures 4 & 5
Operation
Using the PC Interface 17
Using Cal Notepad
3
4
6
6
14
15
16
18 - 19
Tutorial
Fault Finding 28
Page 3 of 32
20 - 27
TTI 4 HANDBOOK
MODEL 944
ISS.04 - 06/06
EMC INFORMATION
This product meets the requirements of the European Directive on Electromagnetic Compatibility
(EMC) 89/336/EEC as amended by EC Directive 92/31/EEC.
T he product meets the susceptibili ty
requirements of EN 50082-1, criterion B.
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
cannot become live in the event of a failure of the insulation.
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.
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HEALTH AND SAFETY INSTRUCTIONS
1. Read all of this handbook before use.
TTI 4 HANDBOOK
MODEL 944
ISS.04 - 06/06
2.
3.
4.
5.
6.
7.
8.
9. If cased, do not return the apparatus to its carrying case until the unit has cooled.
10.
Wear appropriate protective clothing.
Operators of this equipment should be adequately trained in the handling of hot and cold
items and liquids.
Do not use the apparatus for jobs othe r th a n those for which it was designed, ie. the
calibration of thermometers.
Do no t handle the apparatus when it is hot (or cold), unless wearing the appropriate
protective clothing and having the necessary training.
Do not drill, modify or otherwise change the shape of the apparatus.
Do not dismantle the apparatus without disconnecting it from the supply and leaving time
for it to reach ambient temperature.
Do not use the apparatus outside its recommended temperature range.
There are no use r servi ceable parts inside. Contact your nearest Isotech agent for
repair.
11.
12.
13.
Product covered by this document are described in our manual attached.
Ensure materials, especially flammable mat e ri als are kept away from hot parts of the
apparatus, to prevent fire risk.
Ensure adequate ventilation when using oils at high temperatures.
Each apparatus is protected by an over temperature circuit. Please consult handbook
for details.
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TTI 4 HANDBOOK
MODEL 944
ISS.04 - 06/06
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.
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
The Company is always willing to give technical adv i ce and assistance where appropriate.
Equally, because of the programme of continual development and improvement, we reserve the
right to am end or alter characteristics and design without prior notice. This publication is for
information only.
Page 6 of 32
TTI 4 HANDBOOK
MODEL 944
ISS.04 - 06/06
SAFETY PRECAUTIONS
1. Please read this manual before operating the instrument.
2. All warnings, notes, etc. within this manual must be observed.
3. The TTI 4 system is maintenance free. Servicing should be carried out by qualified
personnel only.
4. Disconnect power before servicing or removing parts.
5. When using the TTI 4 any operating conditions that cause damage to objects or danger to
human beings must be avoided.
6. The measuring results of the TTI 4 system not only depend on the correct functioning of
the instrument itself but also depend on various other conditions, such as the calibration of
the surface sensor.
Therefore, the results must be verified by an expert before further steps based on those
results are taken.
7.The compensated surface sensor is often and by its nature HOT. Appropriate precautions
must be observed when handling the sensor.
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TTI 4 HANDBOOK
MODEL 944
ISS.04 - 06/06
INTRODUCTION
Surface temperature measurement with contact thermometers has always been a problem
because of the heat flux from the surface being measured affects the surface temperature, and
the temperature as indicated by the measuring sensor.
The following article describes the problems and the principle of operation of the Isotech True
Temperature Indicator 4.
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TTI 4 HANDBOOK
MODEL 944
ISS.04 - 06/06
TRUE SURFACE TEMPERATURE MEASUREMENT
Summary:
The mechanism of surface tem p e rature sources of error are described. These all have to do
with conduction of heat away from the surface being measured. By thermally compensating for
these conduction mechanisms a new and novel device is described th a t will measure true
surface temperature. This device, already in production and use has reduced errors by up to
95%.
Introduction:
As soon as a measuring device is attached to a surfa ce he at flows from the hot to the cold
surface.
This for a hot surface means that the surface is cooled locally, and that the measuring device
is heated. The rate a t which heat is transferred depends on the thermal contact between
surface and measuring device. Often silicone grease or other conducting material is introduced,
to help conduction. The smoothness of the surface also affects the heat flow.
Wh a t wo ul d b e ideal is a surface sensor that generated an equal and opposite heat flux
reflected back into the surface.
This would eliminate all the errors associated with surface temperature measurement.
Causes of measurement errors:
There are three main problem areas in determining the surface temperature of a solid which is
in equilibrium with the surrounding atmosphere, which we shall call the first, second and third
partial error.
The first partial error results from the loading effect on the object being measured by bringing a
cold measuring probe into contact with it. The heat flow from the surface of the object in contact
with the probe increases from its equilibrium value as flux is drawn up the probe. The result is
a disturbance of the temperature field and a drop in surface temperature at that point. This error
is particularly severe with non-metallic objects where the low thermal conductivity of the object
results in large temperature field disturbances.
The non-ideal contact conditions between the probe and the object surface result in a thermal
resistance at the interface between the two. T h e in te nse heat flux up the probe has to pass
through this resistance, and a temperature drop is experienced, resulting in the second partial
error.
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TTI 4 HANDBOOK
MODEL 944
ISS.04 - 06/06
The third partial error is caused by the temperature drop with distance from the surface of the
object being measured to the sensitive point of the probe which i s re sp on si ble for the
thermometer readings. Due to the physical construction of the probes, this distance, /, is nonzero. Figure 1 shows the effects of these three partial errors on the reading of the contact
thermometer.
These three errors can be represented by the following equations [1]:
1.
R
1= -
2.
2= -
1
3. 3= -
where:
qd = nett heat flux density up probe
qT = total heat flux density up probe
T = total heat flux up probe
RT = radius of the probe
b and T = thermal conductivity of the object probe respectively
W
= contact resistance
c
W
T
T
b
c.T
(
.
F
). q
m
d
q
T
F
and
= constant
m
From these equations it can be seen that all three errors are proportional to either the heat flux
or the heat flux density that flows up the measuring probe d u e to the te m perature gradient
between object and probe. If this h e a t flux can be reduced, then it follows that the errors of
measurement will also be reduced.
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