Isotech 820 Operating Manual

AQUARIUM LARGE

VOLUME LIQUID BATH

MODEL 820

User Maintenance Manual/Handbook

Isothermal Technology Limited, Pine Grove, Southport, PR9 9AG, England

Tel: [phone] Fax: [phone] Internet: www.isotech.co.uk E-mail: [e-mail]

The company is always willing to give technical advice 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.

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Aquarium 820 Iss.06 – 01/13

CONTENTS

EMC INFORMATION...................................................................................................................................................................... 4

ELECTRICAL SAFETY ..................................................................................................................................................................... 4

HEALTH AND SAFETY INSTRUCTIONS .................................................................................................................................. 5

GUARANTEE.................................................................................................................................................................................... 6

TEMPERATURE CALIBRATION USING STIRRED-LIQUID BATHS ..................................................................................... 7

OPENING REMARKS ..................................................................... 7

TEMPERATURE CALIBRATION WITH STIRRED-LIQUID BATHS ....................................... 7

BASIC PRINCIPLES ....................................................................... 8

INFERENCES OF USING SENSORS "NOT DESIGNED FOR CALIBRATION" ............................... 8

SOME THOUGHTS ABOUT CALIBRATORS ..................................................... 9

SUMMARISING PART 1 OF THIS TUTORIAL ..................................................... 9

TWO WRONGS CAN MAKE A RIGHT (APPROXIMATELY) ........................................... 9

CAN SENSORS BE DAMAGED BY THE LIQUIDS IN A STIRRED LIQUID BATH? ............................ 10

APPENDIX; THERMOMETER IMMERSION ............................................................................................................................. 11

PRACTICAL APPLICATIONS ............................................................... 12

Example ..................................................................................................................................................................................... 12

INTRODUCTION .......................................................................................................................................................................... 13

On Arrival ............................................................................ 13

GENERAL LAYOUT ...................................................................................................................................................................... 14

LIQIUD LEVEL ................................................................................................................................................................................ 15

CHANGING LIQUIDS .................................................................................................................................................................. 15

CAUTION ................................................................................................................................................................................... 15

COOLING COIL ............................................................................................................................................................................. 15

USING THE COOLING COIL .............................................................. 15

OPERATING THE CONTROLLER .............................................................................................................................................. 16

FRONT PANEL LAYOUT ................................................................. 16

The Temperature Controller ........................................................................................................................................................ 16

Altering the Setpoint ................................................................................................................................................................... 16

ADVANCED CONTROLLER FEATURES ....................................................... 16

Setpoint Ramp Rate .................................................................................................................................................................... 16

Instrument Address ..................................................................................................................................................................... 17

Monitoring the Controller Status ................................................................................................................................................. 17

Units .......................................................................................................................................................................................... 17

OVERTEMPERATURE CONDITION .......................................................... 17

DIAGNOSTIC ALARMS ............................................................................................................................................................... 18

CONTROLLER ERROR MESSAGES ........................................................... 18

NORMAL RUNNING .................................................................................................................................................................... 19

CAL NOTEPAD .............................................................................................................................................................................. 20

MINIMUM SYSTEM REQUIREMENTS ......................................................... 20

DEVELOPMENT ....................................................................... 20

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License ....................................................................................................................................................................................... 20

CAL NOTEPAD .............................................................................................................................................................................. 21

Minimum System Requirements ............................................................. 21

Development .......................................................................... 21

License ....................................................................................................................................................................................... 21

Installing Cal NotePad .................................................................... 22

Starting Cal NotePad ..................................................................... 22

Protocol ............................................................................. 22

OPTIONAL ACCESSORIES ......................................................................................................................................................... 23

EQUALISING BLOCK (optional) ............................................................. 24

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Symbol Identification

Publication

Description

ISO3864

Caution (refer to handbook)

IEC 417

Caution, Hot Surface

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 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 are
fully screened.

The product meets the susceptibility 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.

Conductive pollution, e.g. Carbon dust, must be excluded from the apparatus. EN61010 pollution degrees 2.

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HEALTH AND SAFETY INSTRUCTIONS

1. Read this entire handbook before use.

2. Wear appropriate protective clothing.

3. Operators of this equipment should be adequately trained in the handling of hot and cold items and liquids.

4. Do not use the apparatus for jobs other than those for which it was designed, i.e. the annealing of
thermometers.

5. Do not handle the apparatus when it is hot (or cold), unless wearing the appropriate protective clothing and
having the necessary training.

6. Do not drill, modify or otherwise change the shape of the apparatus.

7. Do not dismantle the apparatus.

8. Do not use the apparatus outside its recommended temperature range.

9. If cased, do not return the apparatus to its carrying case until the unit has cooled.

10. There are no user serviceable parts inside. Contact your nearest Isotech agent for repair.

11. Ensure materials, especially flammable materials are kept away from hot parts of the apparatus, to prevent
fire risk.

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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, provided the failure is not the
result of misuse. 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 TO PROPERLY 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.

ISOTHERMAL TECHNOLOGY LTD.
PINE GROVE, SOUTHPORT
PR9 9AG, ENGLAND

TEL: [phone]/544611
FAX: [phone]

The company is always willing to give technical advice 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.

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TEMPERATURE CALIBRATION USING STIRRED-LIQUID BATHS

OPENING REMARKS

Practical thermometry is derived by relating the gas laws (Boyle, Charles, Avagadro) to practically realisable devices
such as triple-, freeze- and melt-point cells of various very pure substances.

Calibration is carried out after heat transfer processes have produced thermal equilibrium between apparatus
containing the cell and temperature sensors placed in them.

Energy exchange is governed by the laws of thermodynamics. Such has been the difficulty of understanding this area
of science that only after the first three laws were discovered was the most fundamental property defined.
Consequently, this was called, somewhat incongruously, the zeroth law. It states: "If two systems, in equilibrium,
each have the same temperature as a third, then they also have the same temperatures as each other".

Read the zeroth law a few times and think about it; it is the key factor in being able to make comparison calibrations.
Translated, it says that if a calibrated standard thermometer is at the same temperature as a calibration bath and an
industrial temperature sensor is also at the same temperature as the bath, then the calibrated standard and the
industrial sensor will be at the same temperature as each other.

An intriguing truism also to bear in mind is: "A thermometer measures its own temperature". This, of course, applies
to a contact-type thermometer and refers quite specifically to the sensing element within it. Immediately called into
question is the manner of application of the thermometer to ensure establishment of thermal equilibrium as defined
by the zeroth law. Factors that introduce errors and uncertainties will be discussed later.

TEMPERATURE CALIBRATION WITH STIRRED-LIQUID BATHS

Calibrating thermometers is done at many levels of accuracy. For highest accuracies, freeze-point cells have been
designed, together with Standard Platinum Resistance Thermometers (S.P.R.T.'s) to realise temperatures defined by
the gas laws (upon which laws practical temperature scales are based).

Personnel involved at this level of measurement can easily become dismissive of the problems faced daily by plant
maintenance engineers whose job it is to ensure that temperature sensors, indicators and controllers are reading
correctly. We neglect this area at our peril since it represents the majority of calibrations performed daily and is one
of the most important reasons for introducing temperature scales in the first place.

This tutorial acknowledges, and attempts to redress, the omission, albeit in a simplified and generalised manner.

During the past decade there has been an increase in the use of stirred-liquid baths for industrial calibration work. It
is to the users and would-be users of these products that this tutorial is addressed.

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BASIC PRINCIPLES

The principle implicit in the operation of calibration baths is that of maintaining spatial and temporal uniformity of
temperature in the measuring zone. This represents an ideal situation, although a well-designed bath can provide a
close approximation to these conditions. Mechanical and thermal properties of the heat transfer fluid will both have
an influence on spatial uniformity of temperature in any given system. Heat sources and cooling devices are
necessarily localised and the distribution of energy by way of the thermal transport properties of the fluid will, in
general, require to be supplemented by forced convective mixing to achieve the desired aim. A fluid circulating or
agitating mechanism in conjunction with a suitable configuration of flow-path can be very effective in producing a
sufficiently uniform temperature, provided that the fluid viscosity is low. In practice, different liquids will be employed
to cover the total temperature range applicable to calibration baths.

Bath temperatures are normally controlled by a proportional or proportional-integral-derivative (often called 3-term
or PID) system, sometimes with an auto-tune facility. The very nature of this type of control (as distinct from, say,
the constancy of fixed-point temperatures) inevitably involves the feature of temperature cycling, however small.
Typically, there will be short-term fluctuations superimposed upon longer-term, greater amplitude, fluctuations and
any measurement technique must take this situation into account.

For carefully-executed comparison measurements, neither small short-term swings nor slow long-term drifts need
invalidate the calibration procedure; indeed, making satisfactory calibration measurements is feasible because:

i. The ratios of PRT resistances and emf-deviations between thermocouples of a given type are not particularly

sensitive to small temperature changes (of a magnitude easily realisable by thermostatic controllers) provided
that these changes apply equally to all thermometers involved (no temperature gradients).

ii. It is not difficult to determine a suitable period of time over which to evaluate meaningful average values, if

thought necessary.

iii. Metal blocks of high thermal inertia and conductance can often be used (depending on thermometer size and

shape) to attenuate temperature swings in the bath and to provide good thermal coupling between
thermometers.

INFERENCES OF USING SENSORS "NOT DESIGNED FOR CALIBRATION"

Unlike S.P.R.T.'s, which are designed solely for calibration purposes, the great majority of industrial temperature
sensors are designed with insufficient consideration of their suitability for calibration.

For example, an engineer wished to measure ambient temperature to an accuracy of ±0.001°C. He proposed the
use of a temperature sensor 40mm long. When asked how he proposed to calibrate his sensor, he confessed not
have considered this aspect of his measurement.

Most industrial temperature sensors are designed to penetrate a pipe, or to strap on to a surface, or even to fit into
the wall of a vessel or into a thermowell attached to it.

In a perfect world the industrial temperature sensor would be long enough to calibrate without errors caused by heat
transfer along the stem. Thermocouples and bead thermistors, because of their small size, not only measure
temperature essentially at a point but, also, can be contained in a thermometer tube of small diameter. On the other
hand, sensing elements of industrial platinum resistance thermometers have a length of, typically, 25mm and require
envelopes of relatively large (e.g. 6mm) diameter to contain them; both dimensions constrain the magnitude of
minimum acceptable immersion length to enable a given level of temperature measurement accuracy to be attained.

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