Tegam Budget 874F, Budget 874C, Budget 875F, Budget 875C, Budget 878 Instruction Manual

Budget Series
Digital Thermometer

Instruction manual
Models 874F/C, 875F/C, 878 and 879

TEGAM is a manufacturer of electronic test and measurement
equipment for metrology, calibration, and production test. We
also provide repair, calibration, and other support services for
a wide variety of test and measurement equipment including
RF power sensor calibration systems, RF attenuation meas­urement systems, resistance standards, ratio transformers,
arbitrary waveform generators, micro-ohmmeters, LCR
meters, handheld temperature calibrators, thermometers,
humidity and temperature control devices, and more.

TEGAM also repairs and calibrates test and measurement
equipment formerly manufactured by Elcto-Scientific
Industries (ESI), Gertsch, Keithley Instruments, Lucas
Weinschel, and Pragmatic Instruments. A complete list can be
viewed on our Product Service Directory at www

.tegam.com

For more information about TEGAM and our products, please
visit our website at www

.tegam.com: or contact one of our
customer service representatives at [e-mail] or
800-666-1010.

Ten Tegam Way,
Geneva, Ohio 44041

Telephone: [phone]
Fax: [phone]
E-mail: [e-mail]

This owner’s manual was as current as possible when this product was manufactured.
However, products are constantly being updated and improved. Because of this, some
differences may occur between the description in this manual and the product you
received.

TEGAM, INC.

TEN TEGAM WAY
GENEVA, OH 44041
TEL: [phone]
FAX: [phone]

www.tegam.com

Publication Date: Nov. 1996

Document Number: 874-901-02A

TABLE OF CONTENTS

Specifications . . . . . . . . . . . . . . . . . . . .1

Manual Addenda . . . . . . . . . . . . . . . . . .2

Unpacking and Inspection . . . . . . . . . . . .2

Preparation for Use . . . . . . . . . . . . . . . . .2

Operation . . . . . . . . . . . . . . . . . . . . . . .2

Environmental Conditions . . . . . . . . . . . .4

Safety Symbols and Terms . . . . . . . . . . . .4

Safety Precautions . . . . . . . . . . . . . . . . .4

Maintenance Information . . . . . . . . . . . . .5

Functionality Check . . . . . . . . . . . . . . . .5

Performance Verfication . . . . . . . . . . . . . .5

Battery Installation/Replacement . . . . . . .6

Optional Accessories . . . . . . . . . . . . . . . .7

Warranty Information . . . . . . . . . . . . . . .9

Statement of Calibration . . . . . . . . . . . . .9

Custom Probes to suit your special temperature measurement appli­cations are also available from T egam, Inc. Please call or send your cus­tom probe design to Tegam for price and delivery information.

Additional Instruction Manuals are available. Order the manual
package, T egam Part Number 878-901-01, for a manual and any appli­cable addenda.

Calibration Instructions, are available upon request. Please call or
write.

WARRANTY

Tegam, Inc. warrants this product to be free from defects in
material and workmanship for a period of one year from date of
shipment. During the warranty period, we will at our option,
either repair or replace any product that proves to be defective.

To exercise this warranty, write or call Tegam, Inc. in Geneva,
Ohio. You will be given prompt assistance and return instruc­tions. Send the instrument, transportation prepaid, to the indi­cated servive facility. Repairs will be made and the instrument
returned, transportation prepaid. Repaired products are war­ranted for the balance of the original warranty period, or at least
90 days.

LIMITATION OF WARRANTY

This warranty does not apply to defects resulting from unautho­rized modification or misuse of any product or part. This war­ranty also does not apply to fuses, batteries, or damage from
battery leakage.

This warranty is in lieu of all other warranties, expressed or
implied, including any implied warranty of merchantability or fit­ness for a particular use. Tegam, Inc. shall not be liable for any
indirect, special or consequential damages.

STATEMENT OF CALIBRATION

This instrument has been inspected and tested in accordance
with specifications published by Tegam, Inc.

The accuracy and calibration of this instrument are traceable to
the National Bureau of Standards through equipment which is
calibrated at planned intervals by comparison to certified stan­dards maintained in the Laboratories of Tegam, Inc.

9

Model 8717 Hypodermic Probe for the measurement of soft and semi-soft
materials. Miniature junction responds with one second time constant. All stain­less steel construction is suitable for food industry, biological and chemical appli­cations. Accuracy is ±2.2°C or 0.75%, whichever is greater. Time constant is
1sec (liquids). Max tip temperature is 500°C or 932°F.

Model 8731 Package of 5 miniature thermocouple connectors. Type K (male).
Model 8732 Standard to miniature thermocouple adapter. The female end of

the adapter is on the standard side. The male end of the adapter is on the minia­ture side.

TYPE J PROBES (For Model 879)

Model 8722 Thermocouple Sensor is a three foot, 24 gauge thermocouple

wire that has a beaded thermocouple junction. Accuracy is ±2.2°C or 0.75%,
whichever is greater. Time constant is < 1sec. Max tip temperature is 480°C or
900°F.

Model 8723 Regular General Purpose/Immersion Probe for liquids and
general applications. Accuracy is ±2.2°C or 0.75°, whichever is greater. Time
constant is 1sec (stirred liquids). Max tip temperature is 760°C or 1400°F.

Model 8725 Regular Surface Probe for measurements of flat surfaces of
solids. Keeping the sensor tip flush to most surfaces provides fast responding
measurements. Accuracy is ±2.2°C or 0.75%, whichever is greater. Time con­stant is 3sec (High thermal capacity/conductive solids). Max tip temperature is
400°C or 750°F.

Model 8726 Regular Air/Gas Probe for measurement of air/gasses. Exposed
junction within protection shroud responds to ambient temperature while shield­ed from incident radiation. Accuracy is ±2.2°C or 0.75%, whichever is greater.
Time constrant is 3sec. (5m/s air flow). Max tip temperature is 300°C or 570°F.

TYPE T PROBES (For Models 875F & 875C)

Model 8752 Thermocouple Sensor is a three foot, 24 gauge thermocouple

wire sensor that has a beaded thermocouple junction. Accuracy is a ±2.2°C or

0.75%, whichever is greater. Time constant is <1sec. Max tip temperature is
400°C or 752°F.

Model 8753 Compact General Purpose/Immersion Probe for liquids and
general purpose applications. Has a one foot (5’ extended) coil cord, with a
molded plastic handle. Accuracy is a ±2.2°C or 0.75%, whichever is greater.
Time constant is 2sec (stirred liquids). Max tip temperature is 200°C or 392°F.

Model 8754 Compact Penetration Probe for measurements within soft or
semi-frozen materials. Has a one foot (5’ extended) coil cord, with a molded
plastic handle. Accuracy is ±2.2°C or 0.75%, whichever is greater. Time con­stant is 1sec (stir-red liquids). Max tip temperature is 200°C or 392°F.

Model 8756 Compact Air/Gas Probe for measurement of air/gasses.
Exposed junction within protective shroud responds to ambient temperature
while shielded from incident radiation. Has a one foot (5’ extended) coil cord,
with a molded plastic handle. Accuracy is ±2.2°C or 0.75%, whichever is
greater. Time constant is 1.5sec (5 m/s air flow). Max tip temperature is 300°C
or 570°F.

8

SPECIFICATIONS

TEGAM T.C. TEMPERATURE ACCURACY

2

MODEL TYPE

1

RANGE SPAN RESOLUTION (18° to 28°C; 1 year)

874F K 200°F -40.0° to 199.9°F 0.1° ±(0.5% rdg. + 1.0°F)

2000°F -120° to 1999°F 1° ±(1% rdg. + 2°F)

874C K 200°C -40.0° to 199.9°C 0.1° ±(0.5% rdg. + 0.5°C)

1100°C -85° to 1100°C 1° ±(1% rdg. + 1°C)

875F T 200°F -112.0° to 199.9°F 0.1° ±(0.4% rdg. + 1.1°F)

752°F 200° to 752°F 1° ±(1% rdg. + 2°F)

875C T 200°C -80.0° to 199.9°C 0.1° ±(0.4% rdg. + 0.6°C)

400°C 200° to 400°C 1° ±(1% rdg. + 1°C)

878 K °F -120° to 1999°F 1° ±(1% rdg. + 2°F)

°C -85° to 1100°C 1° ±(1% rdg. + 1°C)

879 J °F -112° to 1400°F 1° ±(1% rdg. + 2°F)

°C -80° to 760°C 1° ±(1% rdg. + 1°C)

GENERAL SPECIFICATIONS

INPUT CURRENT:< 1 microamp, typical.
REPEATABILITY:0.3°F (0.2°C) typical for 1 week at constant ambient temperature.
TEMPERATURE COEFFICIENT: 18° to 28°C; included in accuracy specification.

From -10° to 18°, and 28° to 50°C; less than ±(0.025% of rdg +0.1°C)/°C.

ENVIRONMENTAL LIMITS FOR OPERATING: -10° to 50°C, less than 80% rela-

tive humidity (R.H.) up to 35°C; reduce R.H. limit by 3%/°C from 35° to 50°C.

ENVIRONMENTAL LIMITS FOR STORAGE: -35° to 60°C, less than 90% relative

humidity up to 35°C, reduce R.H. limit by 3%/°C from 35° to 60°C.

DISPLAY: 3 1/2 digit LCD, 13mm (0.5”) height. Polarity indication. Decimal point when

req’d.

CONVERSION RATE: 1.3 readings per second.
OVERRANGE AND OPEN SENSOR INDICATION: 3 least significant digits

blanked.

MAXIMUM COMMON MODE VOLTAGE: 42V peak to earth.
THERMOCOUPLE INPUT: Miniature TC Connector.
POWER: 9V alkaline or carbon-zinc (NEDA 1604) battery.
BATTERY LIFE, CONTINUOUS: 350 hours typical with alkaline; 200 hours typical

with carbon-zinc.

BATTERY INDICATOR: Display indicates “LO BAT” when less than 10% of life

remains.

DIMENSIONS: 160mm long x 69mm wide x 31mm thick (6.3” x 2.7” x 1.2”).

Net weight 210gm (7.5 oz.)

CONSTRUCTION: Heavy duty ABS plastic housing.
ACCESSORIES SUPPLIED: Battery and Instruction Manual.

Specifications subject to change without notice.
1

Type K=NiCr-NiAl Thermocouple, Type T=Cu-CuNi Thermocouple, Type J=Fe-CuNi
Thermocouple.
2

Excludes thermocouple sensor errors.

1

MANUAL ADDENDA

Improvements or changes to this manual will be explained on an
addendum included with the instrument. All changes information
should be incorporated immediately into the appropriate places in the
manual.

UNPACKING AND INSPECTION

Each instrument is inspected both mechanically and electrically before shipment.
Upon receiving your instrument unpack all items from the shipping container and
check for any obvious damage that may have occured during transit. Report any
damage to the shipping agent. Retain and use the original packing materials if
reshipment is necessary.

PREPARATION FOR USE

Each instrument is supplied with a 9 volt battery (See page 6 of this
manual for battery installation instructions). Connect the appropriate
probe to the miniature TC connector located on the top of the instru­ment (just above the display).

OPERATION

The digital thermometer is easy to use. There is only one control (locat­ed on the side of the instrument) that turns the instrument on/off and
selects the range. Use the following procedure to operate the instru­ment:

1. Select the appropriate temperature probe and insert it into the
miniature TC-input connector, located on the top of the instru­ment.

2. Turn on the power to the instrument by selecting the desired
range. Note: For the best accuracy always use the low range
when measuring temperatures below 200°.

3. Make the measurement:
A. Touch the probe tip tothe material to be measured.
B. Read the display.

2

OPTIONAL ACCESSORIES

The following accessories can be used with your thermometer to enhance the
performance of the instrument. These accessories are available through your
local Tegam distributor or the factory.

Model 8660 Tilt Stand/Belt Clip/Probe Holder can be used as a tilt stand
or clipped to your belt. It will hold the instrument and one compact probe.

Model 8668 Soft Carrying Case for all models.

TYPE K PROBES (For Models 874F, 874C & 878)

Model 8711A Thermocouple Kit includes the Model 8712 Thermocouple

Sensor, 6m (20’) of AWG #24 Type-K duplex TC wire, a mininature TC plug and
jack, and a standard TC plug and jack.

Model 8712 Thermocouple Sensor is a three foot, 24 gauge TC wire sensor
that has a beaded thermocouple junction. Accuracy is ±2.2°C or 0.75%,
whichever is greater. Time constant is <1sec. Max tip temperature is 480°C or
900°F.

Model 8713 Regular General/Immersion Probe for liquids and general pur­pose applications. Accuracy is ±2.2°C or 0.75%, whichever is greater. Time con­stant is 1sec (stirred liquids). Max tip temperature is 900°C or 1650°F.

Model 8733 Compact General Purpose/Immersion Probe has a one foot
(5’ extended) coil cord with a molded plastic handle. Accuracy is ±2.2°C or

0.75%, whichever is greater. Time constant is 1sec (stirred liquids). Max tip
temperature is 200°C or 392°F.

Model 8714A Regular Penetration Probe for measurements within soft or
semi-frozen materials. Accuracy ±2.2°C or 0.75%, whichever is greater. Time
constant is 2sec (stirred liquids). Max tip temperature is 900°C or 1650°F.

Model 8734 Compact Penetration Probe has a one foot (5’ extended) coil
cord, with a molded plastic handle. Accuracy is ±2.2°C or 0.75%, whichever is
greater. Time constant is 1sec (stirred liquids). Max tip temperature is 200°C or
392°F.

Model 8715 Regular Surface Probe for measurements of flat surfaces of
solids. Keeping the sensor tip flush to most surfaces provides fast responding
measurements. Accuracy is ±2.2°C or 0.75%, whichever is greater. Time con­stant is 3sec (high thermal capacity/conductive solids). Max tip temperature is
400°C or 750°F.

Model 8716 Regular Air/Gas Probe for measurement of air gasses. Exposed
junction within protective shroud responds to ambient temperature while shield­ed from incident radiation. Accuracy is ±2.2°C or 0.75%, whichever is greater.
Time constant is 3sec (5m/s air flow). Max tip temperature is 300°C or 570°F.

Model 8736 Compact Air/Gas Probe has a one foot (5’ extended) coil cord,
with a molded plastic handle. Time constant is 1.5sec (5m/ air flow). Accuracy
is ±2.2°C or 0.75%, whichever is greater. Max tip temperature is 200°C or
392°F.

7

4. Turn on the instrument and use the following table to verify that
the readings on each range are within specifications.

Table 1. Performance Verification

Model No. Range Reading Model No. Range Reading

874F 200 32.0 ± 1.2°F 879 760 0 ± 1°C

2000 32 ± 2°F 1400 32 ± 2°F

874C 200 0.0 ± 0.5°C 875F 200 32 ± 1.2°F

1100 0 ± 1°C 752 32 ± 2°F

878 1100 0 ± 1°C 875C 200 0.0 ± 0.6°C

2000 32 ± 2°F 400 0 ± 1°C

BATTERY INSTALLATION/REPLACEMENT

WARNING

Turn the instrument off and disconnect the
input probe before removing the bottom
cover. Reinstall the cover before resuming
use of the instrument.

1. Place the unit face down on a bench or other similar surface
and remove the screws from the bottom cover.

2. Separate the bottom cover from the rest of the instrument by

grasping the top of the case (just above the display) and care­fully lifting it away from the display.

3. Remove the old battery.

4. Place the new battery in the battery compartment. Be sure to
observe the proper polarity. Refer to Figure 2.

5. Reinstall the bottom cover before resuming use of the instru­ment.

Figure 2 Battery Installation

6

NOTE

An open sensor or overrange condition is indicated by the
following display.

3

Figure 1.

Model 878 Control Layout

All Others Similar

On/Off Range Switch

3 1/2 Digit Display

Minus Sign Displayed

Plus Sign Implied

Low Battery Indicator

Miniature TC Connector

i

First digit displays
the number one.

Remaining display
blank.

BATTERY

BATTERYTERMINALS

ENVIRONMENTAL CONDITIONS

Operation of the instruments should take place at an ambient temper­ature of -10°C to 50°C (14°F to 122°F), less than 80% relative humid­ity up to 35°C, reduce R.H. limit by 3% per °C from 35°C to 50°C.

SAFETY SYMBOLS AND TERMS

The symbol ! on the instrument denotes that the user should refer
to the operating instructions.

The WARNING used in this manual explains dangers that could
result in personal injury or death.

The CAUTION used in this manual explains hazards that could dam­age the instrument.

SAFETY PRECAUTIONS

1. Do not touch the probe tip when measuring excessively high or low
temperature.

2. Do not exceed 42V peak from the probe tip or input jack to earth

ground.

WARNING

A shock hazard exists on the thermometer
input jacks when probes or sensors are
exposed to voltage levels greater than 42V
peak to earth ground

CAUTION

Do not attempt to measure temperatures
beyond the range of the probe being used.
Probe damage may occur. Maximum probe
temperatures are given in the optional
accessories section.

4

MAINTANCE INFORMATION

This section contains information needed to maintain your instrument.
The following information is included: functional check, performance veri­fication, and battery installation/replacement.

WARNING

The information presented in this section
is intended for use by qualified personnel
only. Turn off the power and remove all
probes from the instrument before replac­ing the battery.

FUNCTIONALITY CHECK

At room temperature hold the tip of a probe sensor between
your thumb and index finger. A reading between 25°C and
40°C (77°F and 104°F) should be observed to confirm func­tionality of the instrument.

PERFORMANCE VERIFICATION

Accuracy Check

The instrument should be at an ambient temperature of 23°C ± 1°C
and a relative humidity of less than 80% during accuracy check.

1. Prepare a pure water ice bath as follows:
A. Drill a hole in the cap of a Dewar flask or thermos to accom-

modate the thermocouple.

B. Firmly pack the flask with pea-size ice cubes made from distill-

ed water and then fill the flask with distilled water.

C. Replace the melted ice with more ice while removing the

excess water.

D. Place the cap on the flask.

2. Connect a TC probe to the input jack of the instrument.

3. Immerse the TC probe into the pure water ice bath and allow
10 minutes for thermal stabilization.

5