OPERATING MANUAL
BAT-12
Microprobe Thermometer
CONTENTS
Section
1.0 INTRODUCTION
2.0 INITIAL INSTALLATION
3.0 OPERATING INSTRUCTIONS
4.0 BATTERY REPLACEMENT
5.0 ANALOG OUTPUT
6.0 TEMPERATURE MEASUREMENT WITH
THERMOCOUPLE SENSORS
7.0 TROUBLE SHOOTING
8.0 CHECKING CALIBRATION
9.0 SPECIFICATIONS
10.0 REPAIRS AND WARRANTY
QX EB BAT-12 Rev 09/01
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OPERATING INSTRUCTIONS FOR BAT-12 THERMOMETER
1.0 INTRODUCTION
The Physitemp BAT-12 thermometer is a compact, portable, digital thermometer for
use in the lab or in the field. It can be used with any Type T thermocouple sensor and
is available in two versions:
BAT-12, for battery operation only, uses a 9V alkaline battery.
BAT-12R, a rechargeable version, is supplied with a 9V Nickel/Metal-Hydride
battery and may be battery operated in the field or AC operated in the lab. A
heavy duty vinyl carrying case is supplied with both versions.
2.0 INITIAL INSTALLATION
2.1 Remove the packing list (usually found in a transparent envelope on the outside of the carton) and unpack the instrument. Check that all items shown on the
packing list are present. Sensor probes ordered with the instrument will be packed in
the same box if small or a separate package if they are longer than 12 inches.
2.2 BAT-12, for battery operation, is supplied ready for use with a 9V alkaline battery already installed. Shipment will include the carrying case and a male plug for
connection to the analog output.
2.3 BAT-12R for AC and battery operation, is supplied with a 9V Nickel/MetalHydride battery installed. This is shipped with a full charge. To recharge or for AC
use, connect the small phono plug on the AC adaptor to the jack on the rear of the
instrument and plug the charger into a live 115V outlet. 14 hours are required for a
complete recharge. Overcharging will not harm the unit. If requested, an adaptor for
220VAC operation can be supplied. A carrying case and male plug for connection to
the analog output are supplied with
the BAT-12R.
2.4 If Tilt Stand TTS-2 has been
ordered, mount the instrument on the
stand by attaching the ball and socket
mount to the threaded fitting on the
underside of the case.
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TTS-2 TILT STAND
3.0 OPERATING INSTRUCTIONS
3.1 The following instructions are found on the metal label fixed to the BAT-12.
They are reprinted here in case the label ever becomes defaced.
3.2 The special indications mentioned in 3.1 alert the user to unusual conditions
and can prevent the recording of erroneous readings.
3.3 When the instrument is switched on and a probe is connected, it should read
room temperature. This is normally about 25°C. Hold the tip of the probe between
the thumb and forefinger; if reading increases to 28-34°C, which is normal skin
temperature, it may be assumed that the instrument is working correctly. If the
instrument reads low, your hand may be cold. BAT-12 reads to 1/10°C.
3.4 Normal use of the thermometer is very simple. Switch ON, apply probe, read
temperature.
4.0 BATTERY REPLACEMENT
4.1 When a colon (:) appears in the center of the ditigal display, the battery needs
to be replaced. However, BAT-12 can be used without significant calibration error
for about one hour after the appearance of the colon.
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TO MEASURE
TEMPERATURE
TEMPERATURE
RANGE
SPECIAL
INDICATIONS
BATTERY
REPLACEMENT
RECORDER
OUTPUT
Insert the plug of any Type T thermocouple
probe into the blue socket marked INPUT.
Switch ON. Apply probe. Read temperature.
Model BAT-12 reads -100° to +200°C
0.1° resolution
Probe is above max. temp. See range
above.
Probe is disconnected or broken
Colon between center digits indicates
low battery.
Switch OFF. Use coin to undo 2 screws in back
and slide case off. Remove battery from clip
and replace with similar 9V battery.
3.5 mm miniature jack socket on front panel.
10mV/°C
MODEL: BAT-12 SERIAL NO.
BAT-12
OPERATING NOTES
PHYSITEMP INSTRUMENTS INC
154 HURON AVENUE, CLIFTON NJ 07013 U.S.A. MADE IN U.S.A.
0
18:88
1
4.2 Switch instrument OFF. Use a coin to undo screws on the back of the case and
slide case off. Remove battery from clip and replace with a similar 9V battery.
For BAT-12, alkaline batteries are recommended. Battery life will be approxi-
mately 160 hours.
For BAT-12R, a suitable 9V rechargeable battery should be used. DO NOT
INSTALL A NON-RECHARGEABLE BATTERY IN BAT-12R. If you accidently try to recharge a non-rechargeable battery it may burst, leak and damage the instrument.
5.0 ANALOG OUTPUT
5.0 A DC output, whose amplitude is approximately proportional to instrument
reading, is provided from the 3.5mm miniature jack on the front panel. A mating plug
is supplied with each BAT-12. This plug may be left in the socket until it is required
for use.
5.1 Use of the analog output with strip chart recorder
The output impedance of BAT-12 is 2 Kilohms, so connection to a potentio-
metric recorder will not affect either the calibration or accuracy.
The analog output is proportional to the input thermocouple voltage and is adequate
for most strip chart recordings where small temperature ranges are involved. The
output bears a non-linear relationship to temperature and, over wider ranges,
thermocouple tables can be used to compensate for linearity changes. Physitemp will
supply a copy of these tables on request.
5.2 Use of the analog output with Physitemp TCAT-1A Temperature Control
and Alarm Unit
BAT-12 with TCAT-1A can be used to control a heating or cooling device such as a
heat lamp or pad. This system is frequently used to control the temperature of animal
cages, etc.
For more information on the TCAT-1A, see our website, www.physitemp.com or call
us at 1-800-452-8510.
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POSITIVE
OUTPUT (SIGNAL)
NEGATIVE
COMMON (RETURN)
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6.1 The thermocouple is a simple and widely accepted device for measuring temperature. It comprises two wires of dissimilar metals fused together to form a junction which produces an electrical output proportional to temperature. The National
Institute of Standards and Technology (NIST Monograph 125, 1974) has tabulated
the voltage/temperature relationships of many commonly used thermocouple pairs;
their tables on Copper-Constantan form the basis for calibration of Physitemp
thermometers.
6.2 At one time, accurate thermocouple temperature measurements needed elaborate potentiometers and reference to a source of known temperature, such as an ice
bath. The advent of modern solid state devices has made possible the design of an
inexpensive thermocouple thermometer which is direct reading. The first of these
was Bailey thermometer BAT-4, which was designed in 1969 and is now in use
throughout the world. Your BAT-12 is an advanced version of the original equipment
using the latest low power digital technology and compensated electronic reference
circuitry.
6.3 As compared with thermistor sensors which were formerly used exclusively in
portable thermometers, thermocouples have these advantages:
(a) Wide temperature range, e.g. -200°C to over +1300°C.
(b) High stability of output.
(c) Interchangeability - no recalibration required.
(d) Accuracy traceable to NIST calibrations.
(e) Low cost; users can even make their own sensors.
(f) Microscopic size when needed, as in Physitemp microprobes.
(g) Nearly instant response.
(h) Better measurement accuracy due to low mass with smaller heat loss.
6.4 The main disadvantage of the thermocouple, low sensitivity, was overcome by
the development of auto zeroing amplifiers which are now used in all Physitemp
thermometers. This type of amplifier is essentially drift-free. It makes possible an
electronic thermometer which is permanently calibrated, just like a mercury thermometer. The following notes may help the user to avoid some of the errors most
frequently made in temperature measurement.
6.5 Faulty measurement technique with any type of thermometer can produce
errors of several degrees. Errors attributed to "out of calibration" equipment can
often be corrected by a simple change of technique.
6.0 TEMPERATURE MEASUREMENT WITH THERMOCOUPLE SENSORS
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6.6 Thermocouple probes, like all other temperature sensing devices, must be
placed so that they reach, as closely as possible, the temperature of the material to be
measured. Probes are tip-sensitive, but when measuring the temperatures of liquids,
semi-solids or hard surfaces, it is not sufficient to bring only the tip into contact with
the material being measured. This is because there will be loss of heat along both the
thermocouple wires and their sheath, so readings will be low. The effect can be
greatly reduced if part of the metal sheath is also placed in contact with the material.
In liquids and semi-solids, the tip and sheath are simply immersed; on solid surfaces,
the sheath is laid against the surface.
Here is a useful rough rule: Heat leakage effects are substantially reduced
when an amount of probe equal to 10 or more sheath diameters is
immersed or laid on the surface. For example, with a probe of 1/16” diameter, 10 x 1/16” = 10/16” = .625” = the minimum immersion depth.
6.7 Errors between thermocouple probes. All Physitemp clinical probes and sensors are
made with thermocouple wire that has been specially tested to meet our own stringent
standards. Our clinical probes are guaranteed accurate to within 0.1oC in the range 050oC. Copper-Constantan (type T) thermocouples from other manufacturers are not
normally this accurate. Probes made from wire to “special limits of error” may be
accurate to ±0.5°C in this range. This interchangeability of sensor, including microprobes, is a major advantage of Physitemp thermocouple thermometers.
6.8 Measurements in Liquids. These are quite easy to make, because there is
good thermal contact between liquid and probe. The latter quickly reaches liquid tem-
perature and readings can be taken within a few seconds.
However, a liquid which has been heated above or cooled below
ambient will be losing or gaining heat, and convection currents
will give rise to temperature variations of up to several degrees.
These variations can be reduced by vigorous stirring. This simple
precaution must always be taken.
6.9 Measurements of Air Temperature. Temperature can vary widely in different
parts of a room; differences of at least several degrees will be noted. When a microprobe is used to indicate air temperature, readings will often fluctuate rapidly,
responding to actual temperature changes caused by air currents. Breathing near the
microprobe will produce wide fluctuations. These effects indicate the sensitivity of
the BAT-12/microprobe combination, due to high discrimination of the instrument
and almost instant response of the probe. Fluctuations can easily be eliminated by
bringing the probe into contact with a metallic object, thus increasing its effective
mass and slowing the response. Using a larger probe will have the same results.
6.10 Measurements on Solid Surfaces. These are most easily made with surface
probes such as our BT-1 and MT-D. The rightangled tip provides the 10 diameters of probe
contact specified in Section 6.6. Straight probes
may also be used, provided that sufficient shaft
length is in contact with the surface to be measured. In general, the smaller the probe, the more
accurately it will measure the surface temperature of a solid. For instance, an MT29 microprobe, because of its small size, needs to be in contact with the surface for
as little as 1/8”. SST-1 has a 1/4” gold disc sensor. Gold is an excellent conductor,
and is non-allergenic and non-polluting. It makes a fine skin surface probe.
6.11 Measurements in Electronics. BAT-12 and ICT-4 provide the quickest and
cheapest method of getting accurate reading on both discreet components and integrated circuits used in electronic equipment. ICT-4 has two important differences
from the regular MT-4 probe. There is a 5 1/2” handle suitable for use in the hand or
in a micromanipulator and the micro-thermocouple protrudes slightly beyond the
steel sheath and has some thermal isolation from it. This probe was designed for use
on areas of 5-100 microns in diameter and is used perpendicular to the surface to be
measured. The heat loss described in 6.3 occurs and temperature readings are slightly low -- normally about 0.5°C low. Each probe can be readily calibrated on a larger surface. First lay it parallel to the surface and note the reading. Then take a reading with it perpendicular to the surface; note the difference. Add this difference to
the subsequent reading when using the perpendicular position.
6.12 BAT-12 with a suitable probe has the ability to measure surface gradients,
giving almost instant readings at each point. This feature enables heat sinks to be
designed without guesswork, for maximum efficiency with minimum metal. It is
equally easy to check the adequacy of thermal bonding between a power transistor
or rectifier and its heat sink. General purpose probe BT-1 is suitable for this and
many other measurements. When probes such as BT-1 and the larger HT-1 and HT-2
are used for surface measurements, speed of response and accuracy can often be
improved by use of a heat conductive material such as ‘thermal grease’ or silicone
grease applied between the probe and surface. Note: BT-1, HT-1 and HT-2 should
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not be used on electrical equipment where voltages are present as the sensor is connected to the stainless steel sheath. The following probes are isolated and suitable for
use on certain electrical equipment: TFT series, RET-1, ESO-1, IT-14, IT-18, IT-21.
Check with out technical department for details.
7.0 TROUBLE SHOOTING
a. Check that the instrument is switched on
b. Replace or recharge batteries
c. Excessive loading on the analog output. Remove the output plug
d. Probe or sensor may be faulty (open circuit). Check by substituting another probe or by a resistance check. All probes should read less than 2000
ohms.) If you do not have a second sensor, bend a paper clip or other suitable
wire into a ‘U’ and insert into the socket instead of the probe. The instrument
should read room temperature.
e. Probe temperature is too high
f. Review measurement technique (Section 6.0)
g. Probe temperature below -100°C
Symptom Check below
Readout not illuminated a, b
Readout indicates 1 e
Readout indicates 0 d
Colon (:) in center of display b
Calibration error suspected c, f, g
7.1
8.0 CHECKING CALIBRATION
8.1 The BAT-12 thermometer can have a ‘worst case’ error of 0.2°C. The ‘worst
case’ is rarely met as it assumes that all sources of error are at their maximum, and
that all are additive.
A further possiblity of error is in the sensor. This is a maximum of 0.1°C at 50°C,
0.2°C at 100°C, rising to 3/8% of reading, i.e. a possible 1.5°C at 400°C. This is the
maximum error for Special Limits Copper-Constantan thermocouples permitted by
ANSI (American National Standards Institute.)
In practice, these errors are usually much lower unless poor measurement techniques
are being applied.
8.2 If errors are suspected, check F in Section 7 should first be made. Then the
instrument should be checked against a glass thermometer with 1/10th degree calibrations traceable to NIST. Note that the calibration of a glass thermometer can be
invalidated by overheating -- ensure that this never happens.
8.3 Bind the thermocouple probe to the tip of the glass thermometer so that they
are close together. Do not compress the glass thermometer bulb.
8.4 Insert probe and thermometer in a Dewar flask or Thermos bottle containing
liquid at a suitable temperature. Do not allow the probe or thermometer to touch the
sides of the vessel. Ensure that the thermometer is immersed to its proper depth.
STIR WELL.
8.5 Allowing for some reading error in the glass thermometer (there can be none
in the digital BAT-12), readings should agree with the limits noted in 8.1. If readings
are outside these limits, the instrument should be returned for further checks. (See
section 10.0.) Recalibration of BAT-12 should not be attempted unless you have an
accurate temperature standard and a voltage standard such as a potentiometer with
one microvolt resolution.
A service manual is available. This includes circuit diagram, servicing information
and calibration instructions. Price is $25.
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9.0 SPECIFICATIONS
Temperature range: -100° to +200°C
Resolution: 0.1°
Accuracy: 0.1° ±1 digit between 0 - 50°C
0.1% ± 1 digit over the full range
Calibration: Conforms to National Institute of Standards
and Technology tables -- (NIST monograph 125)
Ambient Cold Junction ±0.1°C from 0° to 50°C
Temp Compensation:
Readout: 3 1/2 digits, 1/2” liquid crystal numerals
Analog output: 10mV per degree C, approximately
Power Supply: BAT-12: 9V alkaline battery, available everywhere
BAT-12R: AC 115V and NimH rechargeable battery
with charger/adaptor
Dimensions: 5”W x 2.5”H x 6”D
Weight: 2 lbs, including carrying case
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10.0 REPAIRS AND WARRANTY
10.1 If the BAT-12 is to be returned for any reason, please pack it with care and
sent it prepaid to:
Service Department
PHYSITEMP INSTRUMENTS INC
154 Huron Avenue
Clifton, NJ 07013 USA
Please include with the instrument:
1. A note describing any problems encountered
2. The name and telephone number of a person we can contact
3. The complete return address for shipping.
For service information on this instrument contact us at:
Tel: 973-779-5577
Fax: 973-779-5954
E-mail: physitemp@aol.com
10.2 Physitemp Instruments Inc. warrants this system to be free from defects in
material or workmanship for 12 months from date of shipment. Repair or replacement will be made at no charge at the discretion of Physitemp if the defect is not
the result of misuse or abuse. Physitemp accepts no consequential liability for
delay in delivery, alleged faulty performance of the product or any other cause.
Cables and probes are considered expendable and are not covered by this warranty.
For your protection, please pack the item carefully and insure against possible
damage or loss. Physitemp will not be responsible for damage resulting from careless packaging. Please return freight prepaid.
PHYSITEMP INSTRUMENTS INC
154 Huron Avenue
Clifton, NJ 07013 U.S.A.
Tel: 973-779-5577
Fax: 973-779-5954
e-mail: physitemp@aol.com
OPERATING MANUAL
BAT-12
Microprobe Thermometer
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