Tegam 840A, 845, 850, 855 Instruction Manual

840A, 845, 850, 855

Digital Temperature Calibrator - Thermometer

MODEL 840A, 845, 850, 855

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.

Instruction Manual

PN# 840A-901-01CD

Publication Date: November 2019

REV. M

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TABLE OF CONTENT S

TABLE OF CONTENTS

General Information

Common Specifications ...................................................................... .................... 1

Unique Specifications .............................................................................................. 4

Features ............................................................................................................... 5

Manual Addenda .................................................................................................... 5

Unpacking and Inspection ....................................................................................... 6

Safety Information ................................................................................................. 6

Safety Precautions ................................................................................................. 6

Battery Installation/Replacement ..............................................................................8

Memory Backup .................................................................................................... 9

Operation with Rechargeable Battery ....................................................................... 9

Operating Instructions ............................................................................................ 9

1. Diagnostics and Error Messages .................................................................... 9

2. Initial Turn On .......................................................................................... 11

3. Meter Mode Operation (Thermocouple) ........................................................ 12

4. Meter Mode Operation (RTD, Thermistor, Ohms) ........................................... 12

5. Data Logging & Recall ............................................................................... 14

6. Calibrator Mode Operation (Thermocouples) ................................................. 16

7. Calibrator Mode Operation (RTD, Thermistor, Ohms) ...................................... 17

8. Storage and Recall of Calibrator Settings ..................................................... 19

9. Step Function ........................................................................................... 20

10. Ramp Function ........................................................................................ 20

Service Information

1. Calibration Procedures ............................................................................... 21

A. Thermocouple Calibration ...................................................................21

B. Resistance Calibration ........................................................................26

2. Calibration Verification ............................................................................... 30

3. Mechanical Parts Diagram .......................................................... ............. .. 36

Warranty ................................................................. .......................................... 37

Limitation of Warranty .......................................................................................... 37

Statement of Calibration .......................................................................... .............37

MAINTENANCE

DO NOT

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INST

RUCT

IONS WITHIN THIS M

ATTE

MPT ANY SERVICING OTHER

INST

RUCTIONS UNLESS YOU ARE QUALIFIED TO DO SO.

ANUAL ARE FOR USE BY QUALIFIED SE

PERSONNEL ONLY.

THAN THAT CONTAINED IN THE OPERATION

RVICE

I

GENERAL INFORMATION

GENERAL INFORMATION

This manual provides operating instructions and maintenance information for four temperature
instruments. These instruments are high performance calibrator-thermometers capable of
simulating and measuring a wide-variety of sensors. In addition, features such as data storage
and ramping further enhance their versatility.

It is recommended that you read this manual thoroughly, especially the sections on safety, prior
to operating these instruments.

COMMON SPECIFICATIONS

THERMOMETER INPUTS: THERMOCOUPLE; Miniature TC jack. RTD, OHMS, THERMISTOR; T­series instrumentation connector.

CALIBRATOR OUTPUTS: THERMOCOUPLE; Miniature TC jack. RTD, OHMS, THERMISTOR; T­series instrumentation connector.

THERMOCOUPLE TYPES: K, J, T, E, N, B, R, S, G, C, D.

RTD TYPES: 100Ω platinum (α = 0.00385)

1000Ω platinum (α= 0.00385)

THERMISTOR TYPE: 2252Ω (YSI Series 400).

RANGES: K; -200°C to 1372°C, -328°F to 2502°F
J; -210°C to 760°C, -346°F to 1400°F

T; -200°C to 400°C, -328°F to 752°F
E; -230°C to 1000°C, -382°F to 1832°F N; -200°C to 1300°C, -328°F to 2372°F
B; 500°C to 1820°C, 932°F to 3308°F R; 0°C to 1768°C, 32°F to 3214°F
S; 0°C to 1768°C, 32°F to 3214°F
G; 300°C to 2316°C, 572°F to 4201 °F C; 0°C to 2316°C, 32°F to 4201 °F
D; 0°C to 2316°C, 32°F to 4201 °F RTD; -200°C to 850°C, -328°F to 1562°F
THERMISTOR; -40°C to 150°C, -40°F to 302°F
OHMS; 0-999.99
0-9,999.9
0-99,999

ACCURACY: All stated accuracies are exclusive of sensor errors and lead resistance induced

errors. Refer to 'UNIQUE SPECIFICATIONS' for detail accuracy specs.

Ω

Ω

Ω

RESOLUTION: TEMPERATURE; 0.1 °/1° F/C

OHMS; 0.01Ω/0.1Ω/1Ω

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1

GENERAL INFORMATION

REPEATABILITY (1 week at constant ambient temperature):

K, J, T, E, N; ±0.2°F typ.
B, R, S, G, C, D; ±1.0°F typ.
RTD, THERMISTOR; ±0.1 °F typ.
OHMS; ±0.01 % rdg typ.

METER-MODE INPUT-CURRENT (THERMOCOUPLES): 50nA typ.

METER-MODE READING-RATE: 1 reading/second typ.

METER-MODE EXCITATION-CURRENTS:

100Ω RTD; <2mA
1000Ω RTD; <200

999.99Ω; <2mA

9999.9Ω; <200
99999Ω; <50
THERMISTOR; T ≤113°F <50

T> 113°F, <2mA

CALIBRATOR MODE OUTPUT LOAD (THERMOCOUPLES): 500Ω min.

CALIBRATOR-MODE EXCITATION-CURRENTS:

100Ω RTD; 0.5 - 1mA (0.1 - 2mA typ.)
1000Ω RTD; 50 - 100μA (10-200μA typ.)

999.99Ω; Same as 100Ω RTD

9999.9Ω; Same as 1000Ω RTD
99999Ω; 10 - 20μA (1 - 20μA typ.)
THERMISTOR; T ≤113°F, 10 - 20μA

MAXIMUM COMMON MODE VOLTAGE: 42V peak to earth.

KEYPAD: 12 momentary switches with tactile feedback select;

• On/Off

• Change/Enter

• Clear/-0

• Sensor Select/1

• °F/°C/2

• Resolution/3

• Operate/4

• Store/5

• Recall/6

• Calibrator/Meter/Up Ramp/7

• Calibrator Step/Down Ramp/8

• Calibrator Ramp/Meter Hold/9

T> 113°F, 0.5- 1mA

μ

A

μ

A

μ

A

μ

A

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GENERAL INFORMATION

DISPLAY: 5 digit LCD, 0.4" height, polarity indication and decimal point. Annunciators;

• Loaded Memory Locations (10 for data storage, 4 for ramp parameters)

• Low Battery (BAT)

• Number Change Mode (NUM)

• Calibrator Mode (CALIB)

• Meter Mode (METER)

• Operate Mode (OPR)

• Store Mode (STO)

• Recall Mode (RCL)

• Meter Hold (HOLD)

• Scale (°F/°C)

• Sensor Type

POWER OFF CONFIGURATION RETENTION: Instrument retains last selected;

• Sensor Type

• °F/°C Scale

• 0.1°/1° Resolution

• Calibrator/Meter Mode

• Memory Contents (data storage and ramp parameters).

DIAGNOSTICS: Display codes indicate following conditions;

• 'BAT': Low Battery

• 'OPEN': Open Input Thermocouple, RTD or Thermistor.

• 'E-1' (momentary): Invalid Keypad Entry

• 'E-2' (momentary): Ramp Function Not Installed

• 'HI': Temperature Reading or Keypad Entry Exceeds Rating

• 'LO': Temperature Reading or Keypad Entry Too Low For Accuracy

• LCD Test: During power-up, all segments and annunciators enabled momentarily

ENVIRONMENTAL LIMITS FOR OPERATING: 0°C to 50°C, less than 90% relative humidity
(R.H.) up to 35°C; reduce R.H. limit by 3%/°C from 35°C to 50°C.

ENVIRONMENTAL LIMITS FOR STORAGE: -35°C to 60°C, less than 95% relative humidity
(R.H.) up to 35°C; reduce R.H. limit by 3%/°C from 35°C to 60°C.

POWER: 9 volt alkaline battery (NEDA 1604A).

BATTERY LIFE, CONTINUOUS: 10 hrs. typical, alkaline; 3 hrs typical, Ni-Cd (rechargeable).

BATTERY INDICATOR: Display indicates BAT when less than 10% of life remains.

DIMENSIONS, WEIGHT: 7.0" x 2.9 x 1.1". Net weight 12 oz.

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3

GENERAL INFORMATION

UNIQUE SPECIFICATIONS

NOTE: The specifications below are specific to the model(s) as identified by

model number. The difference specifications are in addition to the

• MODEL 840A:

SENSOR SELECTION: K, J, T Thermocouples
ACCURACY: (18°C to 28°C ambient, 2 years):
K, J, T; ±0.5°F (rdg ≥ -50°F).

±0.04% rdg (rdg > 1250°F)

TEMPERATURE COEFFICIENT: From 0°C to 18°C, and 28°C to 50°C;

less than ±(0.006% rdg +0.03°C)/°C.

RAMP FUNCTION: Not Included.

BATTERY LIFE, CONTINUOUS: 16 hrs typical, alkaline; 4 hrs typical, Ni-Cd (rechargeable).

• MODEL 845:

SENSOR SELECTION: K, J, T, E, N, B, R, S, G, C, D Thermocouples
ACCURACY: (18°C to 28°C ambient, 2 years):

K, J, T, E, N; ±0.5°F (rdg ≥ -50°F)

B, R, S, G, C, D; ±1.7°F

TEMPERATURE COEFFICIENT: From 0°C to 18°C, and 28°C to 50°C;
K, J, T, E, N; ±(0.002% rdg + 0.03°C)/°C

B, R, S, G, C, D; ±(0.002% rdg + 0.1°C)/°C

RAMP FUNCTION: Included.

BATTERY LIFE, CONTINUOUS: 16 hrs typical, alkaline; 4 hrs typical, Ni-Cd (rechargeable).

• MODEL 850:

SENSOR SELECTION: K, J, T, E Thermocouples

100Ω Platinum RTD

2252Ω Thermistor

ACCURACY: (18°C to 28°C ambient, 2 years):
K, J, T, E; ±0.5 °F (rdg ≥ -50°F).

OHMS; ±0.04% range

RTD; ±0.2°F (rdg≥ - 50°F) (Calibrator mode)

Thermistor; ±0.5°F

TEMPERATURE COEFFICIENT: From 0°C to 18°C, and 28°C to 50°C;
K, J, T, E; ±(0.006% rdg + 0.03°C)/°C

RTD, THERMISTOR, OHMS; ±(0.006% rdg +0.012% rng)/°C

RAMP FUNCTION: Not Included.

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'COMMON SPECIFICATIONS' found on pages 2-4.

±1.0°F (rdg < -50°F)

±1.0°F (rdg < -50°F)

1,000Ω/100,000Ω Resistance

±0.04% rdg (rdg > 1250°F)

±1.0°F (rdg <-50°F)

±0.5°F (rdg < - 50°F) (Calibrator mode)
±0.2°F ±0.04% rdg (rdg ≥ -50°F) (meter mode)
±0.5°F±0.04% rdg (rdg < -50°F) (meter mode)

4

GENERAL INFORMATION

• MODEL 855:
SENSOR SELECTION: K, J, T, E, N, B, R, S, G, C, D Thermocouples

100Ω/1000Ω Platinum RTD

1,000Ω/10,000Ω Resistance

ACCURACY: (18°C to 28°C ambient, 2 years):
K, J, T, E, N; ± 0.5°F (rdg ≥ -50°F)

±1.0°F (rdg < -50°F)
B, R, S, G, C, D; ±1.7°F
RTD; ±0.2°F (rdg ≥ - 50°F) (Calibrator Mode)

±0.5°F (rdg < - 50°F) (Calibrator Mode)
±0.2°F ±0.04% rdg (rdg ≥ -50°F) (meter mode)
±0.5°F ±0.04% rdg (rdg < -50°F) (meter mode)
OHMS; ±0.02% range
TEMPERATURE COEFFICIENT: From 0°C to 18°C, and 28°C to 50°C;
K, J, T, E, N; ±(0.002% rdg + 0.03°C)/°C
B, R, S, G, C, D; ±(0.002% rdg + 0.1°C)/°C
RTD, OHMS; ±(0.002% rdg + 0.004% rng)/°C

RAMP FUNCTION: Included.

FEATURES

•Combination calibrator, thermometer and datalogger.

•Function selection and numeric data entered via 12 keyswitch color coded keypad.

•Keyswitches have tactile feedback.

•5 digit LCD includes annunciators for operating modes.

•Up to 11 thermocouple types, 2 RTD types, and thermistor.

•1° or 0.1° resolution over temperature range of each sensor.

•°F and °C scales.

•Reading hold mode.

•10 memory locations for saving meter readings and/or calibrator outputs.

•Step mode for quick sequential recall of calibrator outputs from memory.

•Manual/automatic ramping for testing controller setpoints.

•Conforms to ITS-90 thermocouple & RTD tables. Refer to 'Service Information' (page 23) for
more information.

•Dust proof, splash proof, drop proof construction.

•Built-in tilt stand/hanger for bench use or hands free field measurements.

•User friendly programming.

•Retains data and programming, even when turned off.

•Performs diagnostic tests and indicates fault conditions.

•Low battery and open sensor indications.

MANUAL ADDENDA

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

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5

GENERAL INFORMATION

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 occurred during transit. Report any damage to the shipping agent. Retain and use
the original packing materials if reshipment is necessary.

SAFETY INFORMATION

SAFETY SYMBOLS AND TERMS

The symbol

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

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

on the instrument denotes that the user should refer to the operating

instructions.

death.

SAFETY PRECAUTIONS

WARNING

These instruments are intended for use by qualified
personnel trained in the safe operation of electronic testing
equipment. Read the instruction manual thoroughly before
using, to become familiar with the instrument's operations
and capabilities.

Do not touch a temperature probe sheath when measuring
excessively high or low temperatures, or toxic substances.

Do not attempt to measure temperatures beyond the range

of the probe being used. Probe damage or personal injury

could result from exceeding a probe's maximum

Do not substitute a metal part for the nylon screw in the rear

case. Doing so will degrade electrical isolation of the case.

WARNING

WARNING

temperature rating.

WARNING

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6

GENERAL INFORMATION

WARNING

The American National Standards Institute (ANSI) states that

a shock hazard exists when probes or sensors are exposed

to voltage levels greater than 42VDC or 42V peak AC. Do

not use this instrument where voltages at the measurement

surface exceed these levels.

WARNING

The battery is accessible through a cover on the back of the

instrument. To avoid electrical shock hazard, disconnect all

temperature probes and sensors and turn the unit off before

removing the cover.

WARNING

Never use this instrument or any probe or sensor inside a

microwave oven.

CAUTION

Avoid making sharp bends in probe or sensor lead wires.

Bending lead wires at a sharp angle can damage the wire

causing probe failure.

CAUTION

Keep inputs electrically isolated from outputs. Do not

connect an external voltage source between the two

connectors, and avoid any external electrical pathways

between input and output (T2 & T1).

Failure to do so will disturb meter readings and calibrator

output levels. Damage to the instrument is also possible.

Where the meter and calibrator connectors are

simultaneously wired into a system lacking the above

isolation, it is necessary to use an "ungrounded" (i.e.

electrically isolated) probe at the thermometer input.

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7

GENERAL INFORMATION

BATTERY INSTALLATION/REPLACEMENT

A 9V alkaline battery is supplied with the instrument but not installed. Read the following
installation instructions before attempting to install or remove the battery. Replacement batteries
should also be alkaline types.

WARNING

Turn the unit off and disconnect any input/output

connections before replacing the battery. Put the cover

back into place on the battery compartment before

resuming use of the instrument.

1. Remove the cover from the battery compartment by sliding it off in the direction of the
arrow located on the battery cover.

2. Remove the old battery.

3. Place the new battery in the battery compartment. Be sure to observe proper polarity.

4. Re-install the battery cover before resuming use of the instrument.

NOTES:

• Less than 10% of battery life remains when the BAT annunciator turns
on.

• When the battery is excessively discharged, the display is blanked.

• If the instrument is going to be stored for a long period of time or in a
high temperature environment, remove the battery to prevent leakage
damage.

• After a new battery is installed, allow approximately 5 seconds

for display turn-on the first time the unit is turned on. During
this period, microcomputer initialization is performed.

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Figure 1. Battery Installation

8

GENERAL INFORMATION

Vin:

90-110 VAC

108-132 VAC

198-242 VAC

50/60 Hz

50/60 Hz

50/60 Hz

MEMORY BACKUP

During battery replacement, the contents of user-programmed memory (data, operating modes,
etc.) can be saved. Prior to removing the old battery, turn off the instrument, and connect a
Model 80010 battery charger. Then exchange batteries, and disconnect the battery charger. Do
not leave the battery charger connected to instruments with non-rechargeable batteries.

OPERATION WITH RECHARGEABLE BATTERY

Model 80010 provides a 9-volt Ni-Cd battery and recharger suitable for use with the unit. This
battery provides 3-4 hours of continuous operation.

NOTE: Instrument accuracy is degraded while recharging the Ni-Cd battery, and

published specifications do not apply to measurements made during
recharging.

Turn off the instrument to recharge the battery. Allow 7 hours to recharge the battery fully. Then
unplug the recharger to avoid overcharging. Allow 20 minutes after charging before taking
measurements.

MODEL 80010 SPECIFICATIONS

Model

80010/100 80010 80010/220

Vout: 40 VDC @ 5mA 40 VDC @ 5mA 40 VDC @ 5mA

OPERATING INSTRUCTIONS

1. DIAGNOSTICS AND ERROR MESSAGES

Unit self-diagnostics provide fault condition readouts which are described below:

PROBLEM: LIKELY CAUSE:

Blank display, unit does not power-up. (1) Improper battery installation.

Check battery polarity.

BAT Annunciator. (1) Low battery voltage, install a new

Display reads OPEN. (1) No thermocouple, RTD or thermistor

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(2) Dead battery.

battery. If problem persists, consult
factory.

is plugged into the meter input.

9

GENERAL INFORMATION

Display reads E1 momentarily. (1) This indicates that an invalid keypad

entry has been made. Review keystroke
sequence, or consult manual for input
instructions.

Display reads E2 momentarily. (1) Attempt made to activate non-

installed ramp function.

NOTE: RAMP Function enabled on Models 845 and 855 only.

Display reads HI. (1) Meter-mode input-temperature

exceeds rating of selected sensor.

(2) Calibrator-mode keypad-entry

exceeds rating of sensor type.

Display reads LO. (1) Meter-mode input-temperature

too low for accurate measurement.
(2) Calibrator-mode keypad-entry too
low for accurate simulation.

Figure 2. Keypad

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10