Ohaus D52XW50RTR1, D52XW50RTX2, D52XW50RQV3, D52XW50WQR6, D52XW50WQV8 Instruction Manual

Defender Series Base

Service Manual

	TABLE OF CONTENTS
CHAPTER 1 INTRODUCTION ............................................................................................................................		2
1.1	Introduction............................................................................................................................................	2
1.2	Definition of Signal Warning and Symbols ............................................................................................	2
1.3	Safety Precaution ..................................................................................................................................	3
1.4	Service Facilities ...................................................................................................................................	3
1.5	Tools and Test Equipment Required.....................................................................................................	4
1.6	Test Masses Required ..........................................................................................................................	4
1.7	Service Strategy ....................................................................................................................................	4
1.8	Physical Description: Model Defender Series Base..............................................................................	4
1.9	Specifications ........................................................................................................................................	5
1.10	How Load Cells Operate .......................................................................................................................	9
1.11	Load Cell Connection ..........................................................................................................................	10
CHAPTER 2 TROUBLESHOOTING..................................................................................................................		12
2.1	Troubleshooting...................................................................................................................................	12
2.1.1 Checking Load Cells for Trouble .....................................................................................................		12
CHAPTER 3 MAINTENANCE AND REPAIR PROCEDURES ..........................................................................		13
3.1	Preventive Maintenance......................................................................................................................	13
3.1.1	Preventive Maintenance Checklist ..............................................................................................	13
3.2	Replacing the Load Cell ......................................................................................................................	13
3.3	Overload Stop Adjustment ..................................................................................................................	14
CHAPTER 4 TESTING ......................................................................................................................................		17
4.1	Testing.................................................................................................................................................	17
4.2	Load Cell Resistance Checks .............................................................................................................	17
4.3	Calibration with an External Indicator..................................................................................................	17
4.4	Consistency Check..............................................................................................................................	18
4.5	Performance Tests ..............................................................................................................................	18
4.5.1 Off Center Load (Shift) Test ............................................................................................................		19
4.5.2 Adjusting Off Center Load ...............................................................................................................		20
4.5.3	Full Load Test..................................................................................................................................	21
CHAPTER 5 PARTS IDENTOFICATION ...........................................................................................................		22
5.1	Defender series Base: Carbon Steel model........................................................................................	22
5.2	Defender series Base: Stainless Steel model .....................................................................................	24
APPENDIX A. GLOSSARY................................................................................................................................		26

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Defender™ Series Bases Service Manual

CHAPTER 1 INTRODUCTION

1.1Introduction

This service manual contains the information needed for diagnosis and repair of Ohaus Defender series Bases. The contents of this manual are contained in five chapters:

Chapter 1 Introduction – Contains information regarding service facilities, tools and test equipment, test masses, specifications, service strategy, and the mechanical and electronic operation of the Base.

Chapter 2 Troubleshooting – Provides guidelines for evaluating the condition and performance of a Base unit, and a standard troubleshooting methodology to follow, as well as a diagnostic guide.

Chapter 3 Maintenance Procedures – Contains preventive maintenance procedures and disassembly, repair and replacement procedures.

Chapter 4 Testing – Contains guides for operational and performance tests and adjustments.

Chapter 5 Parts Identification – Contains exploded views of Defender series Bases and parts, identifying all serviceable components with parts lists.

Before servicing the Base, you should be familiar with the Instruction Manual which is packed with every base.

1.2Definition of Signal Warning and Symbols

Safety notes are marked with signal words and warning symbols. These show safety issues and warnings. Ignoring the safety notes may lead to personal injury, damage to the instrument, malfunctions and false results.

Signal Words
WARNING	For a hazardous situation with medium risk, possibly resulting in injuries or death if not
	avoided.
CAUTION	For a hazardous situation with low risk, resulting in damage to the device or the property or in
	loss of data, or injuries if not avoided.
Attention	For important information about the product.
Note	For useful information about the product.
Warning Symbols
General Hazard		Electrostatic discharge sensitive
Electric Shock Hazard

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Defender™ Series Bases Service Manual

1.3Safety Precaution

For AC mains powered models:

-Verify that the local AC power supply is within the input voltage range printed on the equipment’s data label. - Only connect the AC power cord to a compatible grounded electrical outlet.

For AC adapter powered models:

-Verify that the local AC power supply is within the input voltage range printed on the AC adapter’s data label. - Only connect the AC adapter to a compatible grounded electrical outlet.

Do not position the scale such that it is difficult to disconnect the power cord from the power receptacle.

This equipment is intended for indoor use and should only be operated in dry locations.

Operate the equipment only under ambient conditions specified in the user instructions.

Do not operate the equipment in hazardous or unstable environments.

Disconnect power from the equipment before cleaning or servicing the equipment.

Service should only be performed by authorized personnel.

Use electrostatic protection measures when handling the printed circuit board.

Only use original replacement parts and accessories.

1.4Service Facilities

To service a scale Base, the service area should meet the following requirements:

Clean and level environment.

Away from magnetic fields such as motors or large transformers.

Free of vibrations such as fork lift trucks close by, large motors, etc.

Stable and level work surface.

Not exposed to direct sunlight or radiating heat sources.

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Defender™ Series Bases Service Manual

1.5Tools and Test Equipment Required

1.Common hand tools

2.Standard electronics tool kit

3.Digital Voltmeter (DVM) capable of reading from 1 mv to 50 V dc.)

4.Megohmeter (50 Volt dc maximum test voltage)

5.Desk magnifier on a stand

6.Ohaus Indicator: Defender 5000, or equivalent commercial indicator

7.A calibrated Torque Wrench N.m. – Ft/Lbs

1.6Test Masses Required

The masses required to test the Ohaus Defender series Bases when connected to an Indicator must meet the requirements of ASTM Class or OIML. Mass values 3kg to 600kg, depending on the Base model. The full scale rated capacity of the Base should be used for Span calibration.

1.7Service Strategy

The Load Cells used in Ohaus Bases are non-repairable. The repair method for the Base is direct replacement of Load Cells with connecting cable and hardware.

The Defender series Base contains the following basic replaceable assemblies: Platform, Load Cell with Connecting Cable, and Down Stop and mounting hardware. There is an exploded view drawing of the Base and associated parts list in Chapter 5. This service manual contains sufficient information to isolate the problem, replace the component, test and restore the Base to its original factory specifications.

1.8Physical Description: Model Defender Series Base

Construction	Platform – Stainless Steel
	Scale Base – Carbon Steel or Stainless steel
	Load Cell – Aluminum
Overloading	Corner Loading –1/2 to 2/3 of Full Capacity
	Safe Overload – 150% of Full Capacity
	Ultimate Overload – 300% of Full Capacity
Operating Environment	Ambient temperature: -10ºC to +40ºC
	Relative humidity: up to 80% at 31ºC, decreasing linearity to 50% at
	40ºC
	Height above sea level: Up to 2,000m
	Operability is assured at ambient temperature -10ºC to + 40ºC

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Defender™ Series Bases Service Manual

1.9Specifications

Complete specifications for the Ohaus Defender series Bases are listed in Table 1-1. When a Base has been serviced, it must meet the specifications listed in the table. Before servicing the Base, determine what specifications are not met.

TABLE 1-1. SPECIFICATIONS FOR DEFENDER SERIES BASES

MODEL

D12RQR

D25RQR

D50RQR

D12RTR

D25RTR

D50RTR

D50RQL

D125RQL

25 lb /

50 lb /

100 lb /

25 lb /

50 lb /

100 lb /

100 lb /

250 lb /

Capacity

12.5 kg

25 kg

50 kg

12.5 kg

25 kg

50 kg

50 kg

125 kg

Approved Resolution

NTEP and Measurement Canada 5000e

Safe Overload

150% of capacity

Capacity

Pan Dimensions

305 x 305 mm

305 x 355 mm

457 x 457 mm

12 x 12 in

12 x 14 in

18 x 18 in

Base Construction

Stainless Steel platform with painted steel frame and rubber leveling feet

Load Cell Capacity

22 kg

50 kg

100 kg

22 kg

50 kg

100 kg

100 kg

200 kg

Load Cell Cable

2 m L x 6-wire

Load Cell Type

350 Ohm, aluminum, single point

Load Cell Excitation

5-15V DC/AC

Load Cell Rated

2mV/V

Output

Load Cell Protection

IP67

Net Weight

6.kg / 13.2 lb

7 kg / 15.4 lb

11.5 kg / 25.4 lb

Shipping Weight

7 kg / 15.4 lb

8 kg / 17.6 lb

13.5 kg / 29.8 lb

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Defender™ Series Bases Service Manual

MODEL

D50RTX

D125RTX

D250RTX

D50RQV

D125RQV

D250RQV

D500RQV

D125RTV

D250RTV

D500RTV

100 lb /

250 lb /

500 lb /

100 lb /

250 lb /

500 lb /

1000 lb /

250 lb /

500 lb /

1000 lb /

Capacity

50kg

125 kg

250 kg

50 kg

125 kg

250 kg

500 kg

125 kg

250 kg

500 kg

Approved

NTEP and Measurement Canada 5000e

Resolution

Safe

Overload

150% of capacity

Capacity

Pan

457 x 610 mm

610 x 610 mm

600 x 800 mm

Dimension

18 x 24 in

24 x 24 in

24 x 31.5 in

s

Base

Constructi

Stainless Steel platform with painted steel frame and rubber leveling feet

on

Load Cell

100 kg

250 kg

500 kg

100 kg

250 kg

500 kg

750 kg

250 kg

500 kg

750 kg

Capacity

Load Cell

2 m L x 6-wire

Cable

Load Cell

350 Ohm, aluminum, single point

Type

Load Cell

5-15V DC/AC

Excitation

Load Cell

Rated

2mV/V

Output

Load Cell

IP67

Protection

Net

21.5 kg / 47.4 lb

31 kg / 68.3 lb

39.2 kg / 86.4 lb

Weight

Shipping

24 kg / 52.9 lb

34 kg / 75.0 lb

42.7 kg / 94.1 lb

Weight

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Defender™ Series Bases Service Manual

MODEL

D2WQS

D5WQS

D12WQS

D12WQR

D25WQR

D50WQR

D25WQL

D50WQL

D125WQL

5 lb /

10 lb /

25 lb /

25 lb /

50 lb /

100 lb /

50 lb /

100 lb /

250 lb /

Capacity

2.5 kg

5 kg

12.5 kg

12.5 kg

25 kg

50 kg

25 kg

50 kg

125 kg

Approved

NTEP and Measurement Canada 5000e

Resolution

Safe

Overload

150% of capacity

Capacity

Pan

254 x 254 mm

305 x 305 mm

457 x 457 mm

Dimensions

10 x 10 mm

12 x 12 in

18 x 18 in

Base

Stainless Steel platform with stainless steel frame and rubber leveling feet

Construction

Load Cell

6 kg

10 kg

30 kg

30 kg

50 kg

100 kg

50 kg

100 kg

200 kg

Capacity

Load Cell

1 m L x 4-wire

2 m L x 6-wire

2.5 m L x 6-wire

Cable

Load Cell

350 Ohm, stainless steel, single point

Type

Load Cell

5-15V DC/AC

Excitation

Load Cell

Rated

2mV/V

Output

Load Cell

IP67

Protection

Net Weight

4.5 kg / 9.9 lb

6 kg / 13.2 lb

12.5 kg / 27.6 lb

Shipping

6 kg / 13.2 lb

7 kg / 15.4 lb

14 kg / 30.9 lb

Weight

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Defender™ Series Bases Service Manual

MODEL	D50WTX			D125WTX		D250WTX	D50WQV	D125WQV	D250WQV	D500WQV
	100 lb /			250 lb /		500 lb /	100 lb /	250 lb /	500 lb /	1000 lb /
Capacity
	50 kg			125 kg		250 kg	50 kg	125 kg	250 kg	500 kg
Approved Resolution						NTEP and Measurement Canada 5000e
Safe Overload Capacity							150% of capacity
Pan Dimensions			457 x 610 mm					610 x 610 mm
				18 x 24 in				24 x 24 in
Base Construction		Stainless Steel platform with stainless steel frame and rubber leveling feet
Load Cell Capacity	150 kg			300 kg		500 kg	150 kg	300 kg	500 kg	750 kg
Load Cell Cable	2 m L x 6-			2.5 m L x 6-wire			2 m L x 6-		2.5 m L x 6-wire
	wire						wire
Load Cell Type						350 Ohm, stainless steel, single point
Load Cell Excitation							5-15V DC/AC
Load Cell Rated Output							2mV/V
Load Cell Protection							IP67
Net Weight			24 kg / 52.9 lb					31.5 kg / 69.4 lb
Shipping Weight			26 kg / 573 lb					35.5 kg / 78.3 lb

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Defender™ Series Bases Service Manual