YOKOGAWA 2768 User Manual

User's

2768

Manual

Precision Wheatstone Bridge

IM 2768-01E

IM 2768-01E

4th Edition: Oct. 2017 (YMI)

Introduction

Thank you for purchasing our Precision wheatstone bridge.
This manual describes the specifications and handling precautions of the Precision wheatstone bridge.
Before using this product, thoroughly read this manual to understand how to use it properly.

Contact information of Yokogawa offices worldwide is provided on the following sheet.
PIM 113-01Z2: Inquiries List of worldwide contacts

Notice regarding This User’s Manual

• The information covered in this User’s manual is subject to change without prior notice.

• Every effort has been made to ensure accuracy in the preparation of this manual.

Should any errors or omissions come to your attention however, please inform YOKOGAWA accordingly.

• YOKOGAWA is by no means liable for any damage resulting from the user’s mishandling of the product.

• This manual is intended to describe the functions of this product.

YOKOGAWA does not guarantee that these functions are suited to the particular purpose of the user.

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IM 2768-01E

Cautionary Notes for Safe Use of the Product

WARNING

When operating the instrument, be sure to observe the cautionary notes given below to ensure correct and
safe use of the instrument.
If you use the instrument in any way other than as instructed in this manual, the instrument’s protective
measures may be impaired.
This manual is an essential part of the product; keep it a safe place for future reference.
YOKOGAWA is by no means liable for any damage resulting from use of the instrument in contradiction to
these cautionary notes.

■ The following safety symbols are used on the instrument and in the manual:

Danger! Handle with Care.
This mark indicates that operator must refer to an explanation in

the instruction manual in order to avoid risk of injury or death of

personnel or damage to the instrument.
This mark indicates earth (ground).

■ Since mishandling the instrument can result in an accident that may lead to
injury or death of the operator, such as an electric shock, be sure to observe

the following instructions.

● Protective Measures

• If a crack appears in the instrument after it has been accidentally dropped or bumped,
the safety-purpose insulation may be damaged.

By all means do not use the instrument, but ask the manufacture for repair.

● Connection

• To avoid electric shock, be sure to apply protective grounding to the grounding terminal.

• Install a protection fuse as shown in the example of measurement.

● Measurement

• Always maintain the instrument within the limits for allowable current, voltage and power,
during operation.

If there is more than one limit for any of these parameters, the lowest limit takes precedence.

● External Power Supply

• Only operate the instrument on a supply voltage no greater than 60 VDC.

● Operating Environment

• Do not operate the instrument in a flammable or explosive gas atmosphere.

• Do not operate the instrument if there is any condensation on it.

● Do Not Remove the Case or Disassemble

• Do not open the case except when replacing batteries.

Only Yokogawa service personnel are authorized to remove the casing or disassemble or

modify the instrument.

Do not attempt to repair the instrument yourself, as doing so is extremely dangerous.

IM 2768-01E

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■ Since mishandling the instrument can result in an accident, such as an electric shock,

CAUTION

that may injure the operator or damage the instrument, be sure to observe

the following instructions.

● Batteries

Do not use a mixture of different types of batteries or a mixture of old and new batteries.
If the instrument will not be used for a prolonged period, remove the batteries before storage.
The battery fluid will leak more readily during long-term storage, resulting in instrument malfunction.

IM 2768-01E

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CONTENTS

Introduction.............................................................i

Cautionary Notes for Safe Use of the Product ..................................ii

1. GENERAL...........................................................1

2. SPECIFICATIONS.....................................................1

3. COMPONENT NAMES AND FUNCTIONS..................................4

4. MEASURMENT.......................................................6

4.1 Preliminary Procedure..............................................6

4.2 Measurement.....................................................8

5. PRECAUTIONS ......................................................9

6. PRINCIPLE .........................................................10

7. FOR MORE EFFECTIVE USE OF THE INSTRUMENT .......................11

7.1 How to Use the Measuring Dial (Rs) ..................................11

7.2 To Connect External Accessory Equipment

(Galvanometer and Power Source) ...................................11

(1) Connection of External Galvanometer..................................11

(2) Connection of External Power Source..................................11

(3) Caution..........................................................11

8. CIRCUIT DIAGRAM ..................................................13

IM 2768-01E

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1. GENERAL

±(0.02% of setting + 0.5 mΩ)

Accuracy: at 23 ± 5°C, less than 75%

Measuring Range and Accuracy:

Precision Wheatstone Bridge 2768 is an instrument designed for measuring DC resistance from

0.1 Ω to 110 MΩ.

This instrument is equipped with a galvanometer and a power source internally,
and the measured value is indicated in-line indication without using any additional equipment externally.
Moreover, this instrument is designed with maximum care for the precision and stability of
resistance elements and also for the insulation of the measuring circuit, and is provided with
a guard terminal and a ground terminal.

Therefore the precision measurement is accomplished with 2768.

2. SPECIFICATIONS

Range

× 100 mΩ

× 1 Ω

× 10 Ω

× 100 Ω

× 1 kΩ

× 10 kΩ

× 100 kΩ

× 1 MΩ

× 10 MΩ

Measuring Range Accuracy Resolution

0.10000 to 1.11110 Ω

1.1111 to 11.1110 Ω

11.111 to 111.110 Ω

0.11111 to 1.11110 kΩ

1.1111 to 11.1110 kΩ

11.111 to 111.110 kΩ

0.11111 to 1.11110 MΩ

1.1111 to 11.1110 MΩ

11.111 to 111.110 MΩ

10 µΩ

100 µΩ

1 mΩ

10 mΩ

100 mΩ

1 Ω

10 Ω

100 Ω

1 kΩ

±0.5 mΩ

±0.02% of setting
±0.01% of setting
±0.01% of setting
±0.01% of setting
±0.02% of setting
±0.02% of setting
±0.05% of setting

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IM 2768-01E