Omega 865, 866 User Manual

®

User’s Guide

http://www.omega.com

e-mail: [e-mail]

Digital Thermometers

Model 865 and 866

omega.com

TM

OMEGA

®

OMEGAnetSMOn-Line Service Internet e-mail

http://www.omega.com [e-mail]

Servicing North America:

USA: One Omega Drive, Box 4047

ISO 9001 Certified Stamford, CT 06907-0047

Tel: [phone] FAX: [phone]
e-mail: [e-mail]

Canada: 976 Bergar

Laval (Quebec) H7L 5A1
Tel: [phone] FAX: [phone]
e-mail: [e-mail]

For immediate technical or application assistance:

USA and Canada: Sales Service: 1-800-826-6342 / 1-800-TC-OMEGA

Customer Service: 1-800-622-2378 / 1-800-622-BEST
Engineering Service: 1-800-872-9436 / 1-800-USA-WHEN
TELEX: 996404 EASYLINK: 62968934 CABLE: OMEGA

SM

SM

SM

Mexico and
Latin America:

Tel: (95) 800-TC-OMEGA
En Espan˜ol: [phone] ext: 2203 e-mail: [e-mail]

SM

FAX: [phone]

Servicing Europe:

Benelux: Postbus 8034, 1180 LA Amstelveen, The Netherlands

Tel: [phone] FAX: [phone]
Toll Free in Benelux: 06 0993344
e-mail: [e-mail]

Czech Republic: Ostravska 767, 733 01 Karvina

Tel: [phone] FAX: [phone]
e-mail: [e-mail]

France: 9, rue Denis Papin, 78190 Trappes

Tel: [phone] FAX: [phone]
Toll Free in France: 0800-4-06342
e-mail: [e-mail]

Germany/Austria: Daimlerstrasse 26, D-75392 Deckenpfronn, Germany

Tel: [phone] FAX: [phone]
Toll Free in Germany: 0130 11 21 66
e-mail: [e-mail]

United Kingdom: 25 Swannington Road, P.O. Box 7, Omega Drive,

ISO 9002 Certified Broughton Astley, Leicestershire, Irlam, Manchester,

LE9 6TU, England M44 5EX, England
Tel: [phone] Tel: [phone]
FAX: [phone] FAX: [phone]

Toll Free in England: 0800-488-488

e-mail: [e-mail]

It is the policy of OMEGA to comply with all worldwide safety and EMC/EMI regulations that
apply. OMEGA is constantly pursuing certification of its products to the European New Approach
Directives. OMEGA will add the CE mark to every appropriate device upon certification.

The information contained in this document is believed to be correct but OMEGA Engineering, Inc. accepts

no liability for any errors it contains, and reserves the right to alter specifications without notice.
WARNING: These products are not designed for use in, and should not be used for, patient connected applications.

TABLE OF CONTENTS

MODEL 865 AND 866 DIGITAL THERMOMETERS

SECTION PAGE

SECTION 1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

SECTION 2 INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2.1 Unpacking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

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

2.3 Verification Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

SECTION 3 OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3.1 Safety Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3.2 Operating Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3.2.1 Model 865. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3.2.2 Model 866. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

SECTION 4 THEORY OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

SECTION 5 SERVICE INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5.1 Performance Accuracy Check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5.2 Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5.2.1 Special Handling of Static-Sensitive Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5.2.2 Disassembly Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

5.2.3 Battery Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

5.3 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

5.4 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

5.4.1 DC Voltage Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5.4.2 A/D Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5.4.3 Waveform Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

SECTION 6 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

6.1 PARTS LIST and Component Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

i

SECTION 1 INTRODUCTION

1.1 GENERAL DESCRIPTION

The OMEGA
large, easy to read, liquid crystal displays (LCD). The input connection for each
instrument consists of a
the available accessory thermistor based probes and sensors. The resistance
value of the thermistor at 25°C (77°F) is 2252 ohms. The instruments are pow­ered by a 9 V battery. Continuous operation of 350 hours is typical with an
alkaline battery or 200 hours typical with a carbon-zinc battery.

The Model 865 measures temperatures on two ranges. The 300°F range
measures temperature from –70°F to 300°F with a resolution of 1°F. The
200° F range measures temperature from –70°F to 199.9°F with a
resolution of 0.1°F.

The Model 866 measures temperature from –55° to 150°C, on one range, with
a resolution of 0.1°C.

1.2 FEATURES

®

Models 865 and 866 are Hand Held Digital Thermometers with

1

⁄4 inch phone jack, which accommodates any one of

• High Accuracy/Resolution/Repeatability—to 0.1°

• Highly Versatile—Many applications with different probe
configurations (probes not supplied)

• Continuous Automatic Linearization—Dual slope A/D

• Warning Indication—Overrange/Open Sensor/Low Battery

• Long-Life Battery—9 V Alkaline (MN-1604)

• Rugged Construction—Heavy-Duty ABS Plastic Housing

SECTION 2 BEFORE USING

2.1 UNPACKING

Remove the packing list and verify that all the equipment has been received.
If there are any questions about the shipment, please call OMEGA Customer
Service Department at [phone].

Upon receipt of the shipment, inspect the container and equipment for any
signs of damage. Take particular note of any evidence of rough handling in
transit. Immediately report any damage to the shipping agent.

The carrier will not honor any claims unless all shipping
material is saved for their examination. After examining
and removing contents, save packing material and carton
in the event reshipping is necessary.

NOTE

1

2.2 PREPARATION FOR USE

The Models 865 and 866 are ready for use, after the battery is installed. To install
the battery, refer to paragraph 5.2.3.

2.3 VERIFICATION CHECK

Install a probe and, at room temperature, hold the tip of the probe between your
thumb and index finger. A reading between 25°C and 40°C should be obtained
for the Model 866, and a reading of 77°F to 104°F should be obtained for the
Model 865, to confirm the functioning of the instrument.

SECTION 3 OPERATION

3.1 SAFETY PRECAUTIONS

A shock hazard exists on the input jack when probes or
sensors are exposed to voltage levels greater than 42 volts,
peak to earth ground. Do not exceed 42 volts, peak to earth
ground

WARNING

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

3.2 OPERATING PROCEDURES

3.2.1 Model 865 (See Figure 3-1)

1. Turn power on by selecting the desired range.

2. Insert appropriate temperature probe into the input jack.

3. Touch the probe tip to the material to be measured and read the
display in degrees Fahrenheit.

CAUTION

NOTE

An open sensor is indicated by a reading on the display of
greater than -100.0°. Overrange is indicated by blanking of
three least-significant digits. Low battery (10% life remaining)
is indicated by LO BAT on the display.

2

Figure 3-1 Model 865 Control Layout

3.2.2 Model 866 (See Figure 3-2)

1. Turn power on. Turning power on also selects the 150°C measurement range.

2. Insert appropriate temperature probe into the input jack.

3. Touch the probe tip to the material to be measured and read the display in
degrees Celsius.

An open sensor is indicated by a reading on the display of
greater than -100.0 °. Overrange is indicated by blanking of
the three least-significant digits. Low battery (10% life remain­ing) is indicated by LO BAT on the display.

NOTE

3

SECTION 4 THEORY OF OPERATION

The temperature sensor is thermistor based. The thermistor sensor is a negative
temperature coefficient device. This means that as the temperature increases,
the resistance of the thermistor decreases. This relationship is a logarithmic func­tion. The current that flows through the sensor is inversely proportional to the
resistance of the sensor (Ohm’s Law).

U104B and associated resistors minimize the “on” resistance of the gates of
U101A and B. The input signal must be conditioned by the Log Ratio amplifier,
before being digitized by the A/D converter. The Log Ratio amplifier operates on
two phases: the signal phase and the zero phase.

Each phase has a duration equal to
converter (U102).

Figure 3-2 Model 866 Control Layout

1

⁄2 of the backplane period of the A/D

4

In the signal phase (see Figure 4-1), the source voltage VSis connected to the sen­sor R

. The current that flows through RTalso flows into the collector of Q101. The

T

output voltage of U104C is charged on capacitor C106. Also during this phase, the
input to U104A is grounded and the voltage developed is charged on capacitor
C105.

In the zero phase, the two charged values of voltage are transferred to other parts
of the circuit, as depicted by Figure 4-2. The source voltage V
from the sensor and connected to a zero reference resistor R
flows through R

also flows in the collector of Q101. The output voltage of U104C

Z

is disconnected

S

. The current that

Z

is connected REF LO on U102 by way of C106 and U103B (see Schematic
Diagram 866-106 or 865-106). The voltage that is applied to the input of U104A
and across C111 is the difference between the output voltage of U104C and the
voltage that was charged on C106 during the signal phase.

The voltage charged on C105 is now opposing the output of U104A and therefore
transferred to C110. This is the voltage digitized by the A/D converter (U102). The
fixed reference HI voltage for U102 is provided by current source U105 and its
associated resistors.

Figure 4-1 Signal Phase

5