MARTINDALE DT73 User manual

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Martindale Electric Company Limited
Metrohm House, Penfold Trading Estate, Imperial Way, Watford WD24 4YY, UK
Tel: [phone] Fax: [phone]
E-mail: [e-mail]
Website: www.martindale-electric.co.uk
© 2012 Martindale Electric Company Ltd.
Registered in England No. 3387451. E. & O.E. Document Rev1 LITDT73/75
DT73/DT75
DIGITAL THERMOMETER
INSTRUCTION
MANUAL

GENERAL SAFETY INFORMATION: Always read before proceeding.
Warning
These instructions contain both information and warnings that are necessary for
the safe operation and maintenance of this product. It is recommended that you
read the instructions carefully and ensure that the contents are fully understood.
Failure to understand and to comply with the warnings and instructions can result
in serious injury, damage or even death.
In order to avoid the danger of electrical shock, it is important that proper safety
measures are taken when working with voltages exceeding 30V AC rms, 42V AC
peak or 60V DC.
This product must only be used by a competent person capable of interpreting the
results under the conditions and for the purposes for which it has been
constructed. Particular attention should be paid to the Warnings, Precautions and
Technical Specifications. Always check the unit is in good working order before
use and that there are no signs of damage to it. Do not use if damaged.
Where applicable other safety measures such as use of protective gloves, goggles
etc. should be employed.
Please keep these instructions for future reference. Updated instructions and
product information are available at: www.martindale-electric.co.uk
REMEMBER: SAFETY IS NO ACCIDENT
MEANING OF SYMBOLS:
Specification
DT73/DT75
Digital Thermometer
Equipment complies with relevant EU Directives
Caution - risk of danger & refer to instructions
Caution - risk of electric shock
Equipment protected by double or reinforced insulation (Class II)
End of life disposal of this equipment should be
in accordance with relevant EU Directives
Direct current (DC)
Alternating current (AC)
Earth (ground)
Input protection: 60V DC or 24V AC rms maximum input voltage on any
combination of input pins
Input connector: Accepts standard miniature thermocouple connectors (flat
blades spaced 7.9mm. center to center)
TT1P thermocouple probe:
4-foot Type K thermocouple bead probe (teflon tape insulated)
Maximum insulation temperature 260°C (500°F)
Probe accuracy ± 2.2°C or ± 0.75% of reading (whichever is greater)
GENERAL
Display: 3½ digit liquid crystal display (LCD) with maximum reading of 1999
Reading rate: 2.5 times per second.
Ambient operating range: 0°C to 50°C (32°F to 122°F)
Storage temperature: -20°C to 60°C (-4°F to 140°F)
Relative humidity: 0% to 80% (0°C to 35°C) (32°F to 95°F)
0% to 70% (35°C to 50°C) (95°F to 122°F)
Power: Single standard 9V battery (PP3, NEDA 1604, or equivalent)
Battery life: 200 hours typical with carbon zinc battery
Dimensions: 147 mm (H) x 70 mm (W) x 39 mm (D)
Weight: Approx. 210g including battery
Approx. 337g including battery and holster
Includes: Rubberised holster, TT1P Type K thermocouple probe (x2 for
DT75), Velcro strap, 9V battery (installed) and instructions
SAFETY:
BS EN 61010-1 50V
Class II Double Insulation
Pollution Degree: 2
EMC: Conforms to BS EN 61326-1

Thank you for buying one of our products. For safety and full
understanding of its benefits please read this manual before
use. Technical support is available from 01923 441717 and
[e-mail].
CONTENTS
1 Introduction 1
1.1 Inspection 1
1.2 Description 1
1.3 Accessories 1
1.4 Battery Installation 1
2 Product Specific Safety Information 2
2.1 Precautions 2
3 Operation 3
3.1 General 3
3.2 Low Battery Indication 3
3.3 Description of Press Buttons 4
3.4 Description of LCD Symbols 5
3.5 Temperature Scale Selection 5
3.6 Display Resolution Selection 5
3.7 MAX Function 6
3.8 Data Hold 6
3.9 Temperature Measurement 6
3.10 Differential Temperature Measurement 7
3.11 Temperature Offset Adjustment 7
4 Maintenance 8
4.1 Battery Replacement 8
4.2 Calibration 8
4.3 Cleaning 8
4.4 Repair & Service 9
4.5 Storage Conditions 9
5 Warranty 10
Specifications
All specified accuracies are at 23°C ± 5°C, <75% RH for 1 year, not
including thermocouple error
Temperature coefficient: 0.1 x (specified accuracy) per °C. (0°C to 18°C,
28°C to 50°C)
Temperature scale: Celsius or Fahrenheit user-selectable
Thermocouple type: K
Measurement range: -50°C to 1300°C. (-58°F to 2000°F)
Note: Measurement range will be limited by the range of the thermocouple
probe used
Resolution: 0.1° to 199.9°C/°F, 1° ≥ 200°C/°F
Temperature accuracy:
DT73: -50°C to 1000°C ± (0.3% of rdg + 1°C)
1000°C to 1300°C ± (0.5% of rdg + 1°C)
-58°F to 2000°F ± (0.3% of rdg + 2°F)
DT75: -50°C to 0°C ± 2°C
0°C to 1000°C ± (0.3% of rdg + 1°C)
1000°C to 1300°C ± (0.5% of rdg + 1°C)
-58°F to 32°F ± 4°F
32°F to 2000°F ± (0.3% of rdg + 2°F)
Specification
DT73/DT75
Digital Thermometer

1. INTRODUCTION
1.1 Inspection
Examine the shipping carton for any sign of damage. Inspect the
unit and any accessories for damage. If there is any damage then
consult your distributor immediately.
1.2 Description
The DT73 and DT75 are portable, 3½ digit, compact thermometers
for use with Type K thermocouples. The measuring range is from
-50°C to 1300°C (-58°F to 2000°F). The DT73 and DT75 have
maximum reading and data hold functions.
The DT75 is dual input and may be used in differential mode when
thermocouples are connected to both inputs.
1.3 Accessories (included)
The DT73 and DT75 come with the following accessories:
Rubberised holster
TT1P type K thermocouple probe (x2 for DT75)
Velcro strap
9V battery (installed)
Instructions
1.4 Battery Installation
Refer to Section 4.1 (Battery Replacement) for the battery
installation instructions for the DT73 and DT75.
110
5. WARRANTY AND LIMITATION OF LIABILITY
This Martindale product is warranted to be free from defects in material
and workmanship under normal use and service. The warranty period
is 2 years and begins on the date of receipt by the end user. This
warranty extends only to the original buyer or end-user customer, and
does not apply to fuses, disposable batteries, test leads or to any
product which, in Martindale’s opinion, has been misused, altered,
neglected, contaminated, or damaged by accident or abnormal
conditions of operation, handling or storage.
Martindale authorised resellers shall extend this warranty on new and
unused products to end-user customers only but have no authority to
extend a greater or different warranty on behalf of Martindale.
Martindale's warranty obligation is limited, at Martindale's option, to refund
of the purchase price, free of charge repair, or replacement of a defective
product which is returned to Martindale within the warranty period.
This warranty is the buyer’s sole and exclusive remedy and is in lieu of
all other warranties, expressed or implied, including but not limited to
any implied warranty of merchantability or fitness for a particular
purpose. Martindale shall not be liable for any special, indirect,
incidental or consequential damages or losses, including loss of data,
arising from any cause or theory.
Since some jurisdictions do not allow limitation of the term of an
implied warranty, or exclusion or limitation of incidental or
consequential damages, the limitations and exclusions of this warranty
may not apply to every buyer. If any part of any provision of this
warranty is held invalid or unenforceable by a court or other decision-
maker of competent jurisdiction, such holding will not affect the validity
or enforceability of any other provision or other part of that provision.
Nothing in this statement reduces your statutory rights.

2. PRODUCT SPECIFIC SAFETY INFORMATION
Test Equipment Without A Rated Measurement Category is
applicable to testing and measurement of circuits not connected
directly to the MAINS supply. If test and measurement equipment
does not have a CAT marking then it should be regarded as a
maximum of 50V rating unless otherwise specified.
2.1 Precautions
This product has been designed with your safety in mind, but please
pay attention to the following warnings and cautions before use.
Warning
This unit must NOT be connected to CAT II, CAT III or CAT IV circuits.
Warning
Before use check the unit for cracks or any other damage. Make sure
the unit is free from dust, grease and moisture. Also check any
associated leads and accessories for damage. Do not use if damaged.
Warning
Do not use if the battery/fuse cover is not fitted.
Warning
To avoid electrical shock, and damage to the instrument, do not use
this instrument and the associated temperature probe when voltages
at the measurement surface exceed 24V AC rms or 60V DC.
Caution
To avoid burns or damage to equipment, do not take temperature
measurements inside microwave ovens.
Caution
Avoid severe mechanical shock or vibration and extreme
temperature.
9 2
4.4 Repair & Service
There are no user serviceable parts in this unit other than those
that may be described in section 3. Return to Martindale Electric if
faulty. Our service department will quote promptly to repair any
fault that occurs outside the guarantee period.
Before the unit is returned, please ensure that you have checked
the unit, batteries, fuses, poor connections and leads.
4.5 Storage Conditions
The instrument should be kept in warm dry conditions away from
direct sources of heat or sunlight, and in such a manner as to
preserve the working life of the unit. It is strongly advised that the
unit is not kept in a tool box where other tools may damage it.

3. OPERATION
3.1 General
If the thermometer displays OL then the measurement limits of the
range have been exceeded.
The maximum temperature measurement of the DT73/DT75 is
1300°C (2000°F), but the thermocouple probe being used may
be specified to a lower temperature. For example, the TT1P
supplied is specified to 260°C (500°F). Be sure that the
thermocouple probe is adequate for the measurement being
made.
3.2 Low Battery Indication
If the symbol is displayed then the battery needs replacing
(see section 4.1 Battery Replacement).
3 8
4. MAINTENANCE
4.1 Battery Replacement
To avoid shock or injury, disconnect the thermocouple/s from
any external surface and remove before proceeding.
Using a Phillips screwdriver, remove the three screws from the
back of the meter, and lift off the front cover.
Replace the battery with a new standard 9V battery (PP3, NEDA
1604, or equivalent) observing correct polarity.
NOTE: It is essential to transfer the protective insulating sleeve
from the old battery to the new battery.
Replace the front cover and re-install the screws.
4.2 Calibration
To maintain the integrity of measurements made using your
instrument, Martindale Electric recommends that it is returned at
least once a year to an approved Calibration Laboratory for
recalibration and certification.
Martindale Electric is pleased to offer you this service. Please
contact our Service Department for details.
Email: [e-mail]
Tel: [phone]
4.3 Cleaning
The unit may be cleaned using a soft dry cloth. Do not use moisture,
abrasives, solvents, or detergents, which can be conductive.

3.3 Description of Press Buttons
3.10 Differential Temperature Measurement (DT75 Only)
Connect Type K thermocouple probes, suitable for the type of
temperature measurement and temperature range being made, to
the thermocouple input sockets T1 and T2.
Taking all necessary safety precautions position the thermocouples
at the surfaces to be measured.
Press the T1-T2 button. The LCD displays the symbol.
The difference between the measured temperatures of
thermocouples T1 and T2 will be displayed.
3.11 Temperature Offset Adjustment
The offset adjustment allows an individual Type K thermocouple to
be optimised for the best measurement accuracy at a chosen
reference temperature.
Connect the thermocouple to the input socket and select 0.1°
display resolution.
Place the thermocouple in a known, stable temperature environment
at the reference temperature.
Allow the readings to stabilize.
Slowly adjust the OFFSET so that the thermometer reading matches
the temperature of the known environment.
Leave sufficient time between adjustments to allow for measurement lag.
The calibration of the thermometer-thermocouple combination is
now optimized for measurements at the reference temperature.
The factory setting for the offset adjustment is 0.0°C (32.0°F).
T1-T2
7 4
DT73
ON Powers up the DT73
OFF Powers down the DT73
MAX Selects/deselects the
maximum reading function
HOLD Selects/deselects the data
hold function
0.1° Selects 0.1° resolution
1° Selects 1° resolution
°C Selects the Celsius
temperature scale
°F Selects the Fahrenheit
temperature scale
DT75
ON/OFF Powers up/down the DT75
F/C Selects the Celsius/Fahrenheit
temperature scales
MAX Selects/deselects the
maximum reading function
HOLD Selects/deselects the data
hold function
0.1°/1° Selects 0.1°/1° resolution
T1 Selects thermocouple T1 input
T2 Selects thermocouple T2 input
T1-T2 Selects differential input mode

3.4 Description of LCD Symbols
MAX Maximum reading function is selected
Thermocouple T1 input is selected (DT75 only)
Thermocouple T2 input is selected (DT75 only)
Differential input mode is selected (DT75 only)
°C Degrees Celsius temperature scale is selected
°F Degrees Fahrenheit temperature scale is selected
Indicates battery is low
hold function is selected
3.5 Temperature Scale Selection
Readings are displayed in either degrees Celsius (°C) or degrees
Fahrenheit (°F).
To select the Fahrenheit (°F) scale press the °F (DT73) F/C (DT75)
button. The LCD displays the °F symbol.
To select the Celsius (°C) scale press the °C (DT73) F/C (DT75)
button. The LCD displays the °C symbol.
On power up, the instrument defaults to the scale last selected
before power down.
3.6 Display Resolution Selection
The display resolution can be set to 0.1° or 1° below 200.0°C/°F.
Above 199.9°C/°F OL will be displayed if 0.1° resolution is selected.
To select 1° resolution press the 1° (DT73) 0.1°/1° (DT75) button.
To select 0.1° resolution press the 0.1° (DT73) 0.1°/1° (DT75)
button.
T1
T2
T1-T2
D-H
3.7 MAX Function
Press the MAX button to activate the maximum reading function.
The latest maximum reading will be continually updated and
displayed. The LCD displays the MAX symbol.
When in the maximum reading function, pressing the HOLD button
will stop the update. Press HOLD again to resume updating.
Press the MAX button to exit the maximum reading function.
3.8 Data Hold
To hold a displayed reading press the HOLD button. The LCD
displays the symbol.
To exit data hold press the HOLD button.
3.9 Temperature Measurement
Connect a Type K thermocouple probe, suitable for the type of
temperature measurement and temperature range being made, to
the thermocouple input socket (T1 or T2 or both on the DT75).
For the DT75 only press either the T1 or T2 button to select the
thermocouple input to be displayed. The LCD displays the or
symbol according to the input selection.
Taking all necessary safety precautions position the thermocouple
at the surface to be measured and read the measured temperature
from the display.
Note: Repeated flexing can break the thermocouple leads. To
prolong lead life, avoid sharp bends in the leads, especially near
the connector.
D-H
T1
T2
5 6