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3-11

CHAPTER 3 SCALE TESTING AND CALIBRATION

3.6.4 Linearity Test

The linearity test is used to determine the linearity of the scale throughout its operating range. The results
should be in accordance with the specifications shown above. The reference mass should be approxi-
mately 1/8 of the full-capacity of the scale.

NOTE

: : 

: : The scale must pass the Off-Center Load test and Repeatability Test 

before

 the Linearity Test is

performed.

BE CERTAIN TO USE THE SAME REFERENCE MASS THROUGHOUT THE LINEARITY TEST.

1. Press 

ZERO

     to zero the display.

2. Place the reference mass on the center of the Platform and record the exact value (all decimal

places) displayed.

3. Remove the reference mass and verify that the display returns to zero.  If it does not, disregard the

reading, press 

ZERO

     to rezero the display, and take the reading again.

4. Place a mass equal to 1/4 of the full scale capacity on the Platform and press 

ZERO

.

5. Add the reference mass to the center of the Platform and record the exact value displayed.

6. Remove the reference mass and verify that the display returns to zero.  If it does not, disregard the

reading, press 

ZERO

 to rezero the display, and take the reading again.

7. Place a mass equal to 1/2 of the full-scale capacity on the Platform and press 

ZERO

.

8. Add the reference mass to the center of the Platform and record the exact value displayed.

9. Remove the reference mass and verify that the display returns to zero.  If it does not, disregard the

reading, press 

ZERO

 to rezero the display, and take the reading again.

10.Place a mass equal to 3/4 of the full scale capacity on the Platform and press 

ZERO

.

11.Add the reference mass to the center of the Platform and record the exact value displayed.

12 Remove the reference mass and verify that the display returns to zero.  If it does not, disregard the

reading, press 

ZERO

 to rezero the display, and take the reading again.

13. Calculate the weight differences between the reading as shown in the recorded readings.

14. The Maximum difference should be less than or equal to the Linearity specification for the

scale.

Содержание EB3

Страница 1: ...EB SERIES SCALES SERVICE MANUAL 99 Washington Street Melrose MA 02176 Phone 781 665 1400 Toll Free 1 800 517 8431 Visit us at www TestEquipmentDepot com...

Страница 2: ......

Страница 3: ...ration assumes no liability arising from the use or misuse of this material Reproductionofthismaterialisstrictlyprohibited Material in this manual is subject to change Copyright 2006 Ohaus Corporation...

Страница 4: ......

Страница 5: ...g and Calibration 3 1 3 1 Testing the AC Adapter 3 1 3 2 Testing the Membrane Switch 3 1 3 3 Testing the Load Cell Assembly 3 2 3 3 1 Resistance Test 3 2 3 3 2 Excitation and Output Voltage Test 3 2 3...

Страница 6: ...7 4 3 3 LCD Replacement 4 8 4 4 Replacing the Load Cell Assembly with frame 4 9 4 5 Replacing the Load Cell Component 4 11 4 5 1 Overload Protection Stop Adjustment 4 12 4 6 Replacing the Battery 4 1...

Страница 7: ...and calibration Chapter 4 Repair Procedures Contains detailed repair procedures for all major components Chapter 5 Parts Lists Contains overall views identifying all major serviceable replacement comp...

Страница 8: ...e EB Series Scales must meet the requirements of ASTM Class 4 or OIML Class F2 The mass values are listed in Table 1 1 TABLE 1 1 CALIBRATION MASSES MODEL Calibration Cal in kg MassesTotaling EB3 3kg E...

Страница 9: ...l types of problems that could be encountered with the scale The troubleshooting tables refer to an interconnection diagram in Section 3 to assist in locating the problem 2 1 SCALE WILL NOT TURN ON WI...

Страница 10: ...d lead and0ohmsfortheblacklead Ifanopen conditionexists replacewiringandcon nector as necessary If OK proceed Refer to Section 3 2 and test the Mem brane Switch Replace if necessary See Repair Procedu...

Страница 11: ...r proceedwithPerformanceTestsinSec tion 3 6 TABLE 2 4 NO DISPLAY OR PARTIAL DISPLAY SYMPTOM Displayisnotonorpartialchar acters are displayed PROBABLE CAUSE Display PC Board is defec tive or LCD may be...

Страница 12: ...be tested in accordancewithSection3 4 TheMain PC Board if defective should be re placed See Repair Procedures 4 3 After repair proceed with performance Tests in Section 3 6 SYMPTOM Scale can be turne...

Страница 13: ...tly EnsurethePlatformisemptybeforeswitch ing the scale on Test the Load Cell refer to Section 3 3 If defective replace see Section 4 4 After repair proceedwithPerformanceTestsin Section 3 6 The Main P...

Страница 14: ...2 6 CHAPTER 2 DIAGNOSIS...

Страница 15: ...Plug the AC Adapter into the scale and measure the voltage on the battery terminals Turn the scale on The voltage should be 6 5 Volts dc minimum and 7 5 Volts dc maximum If the voltage is below or abo...

Страница 16: ...res 2 5 415 15 Ohms Wires 3 4 350 3 Ohms NOTE Wires 2 3 4 and 5 must be isolated from chassis ground and shield Resistance should be greater than 5 megohms A lower reading indicates a short in either...

Страница 17: ...e 3 3 indicates typical readings actual values can vary but should remain linear throughout the entire range If readings are out of tolerance replace the Load cell See Section 4 4 or 4 5 for Load Cell...

Страница 18: ...ure 3 2 Interconnection Diagram which illustrates the interconnections to the Main PC Board and is shown as a top view 7 Turn the scale on 8 Using a DVM measure the excitation voltage across EXE and E...

Страница 19: ...ng test leads in place of the load cell Make sure connections are correct 6 Connect a known good AC Adapter to the scale and connect to a power source 7 Turn on the scale an error may be displayed Thi...

Страница 20: ...s DoNOTdisposeofthebatteryinincinerators orcrushortrytoopen Disposeofthe defective battery in accordance with local regulations for lead acid type batteries CAUTION Checkthebatteryforanysignofirregula...

Страница 21: ...voltage should be above 6 0 Volts dc ten minutes after charging stops NOTE If the scale operates less than 80 hours charge the battery and turn on the scale and test how long the scale operates If the...

Страница 22: ..._____ Zero Return ____________ Mass Used ____________ Accurate performance of the EB Series Scales is determined by a series of three performance tests Repeatability Test Off Center Load Test and Line...

Страница 23: ...ng Mean Sum of Readings 10 Delta Reading Mean Standard Deviation The Square root of the sum of the Delta x Delta 9 5 Add the ten readings and divide the total by 10 to find the Mean average Mean Readi...

Страница 24: ...button to return the reading to zero 5 Slide the mass halfway between the center and the left edge of the Platform and record the reading 6 Slide the mass to the center of the weighing surface and pre...

Страница 25: ...s to the center of the Platform and record the exact value displayed 6 Remove the reference mass and verify that the display returns to zero If it does not disregard the reading press ZERO to rezero t...

Страница 26: ...l scale capacity ________________ Reading 3 reference weight added at 1 2 full scale capacity ________________ Reading 4 reference weight added at 3 4 full scale capacity ________________ CalculateDif...

Страница 27: ...d 7 Function menbrane switch M Units Zero Tare Check Count Zero Range 4 of Full Scale Capacity Tare Range Full Capacity by Subtraction except EB15 up to 10kg only Stabilization Time 2 seconds Operatin...

Страница 28: ...l At this time a different calibration weight value can be entered by pressing 3 Place the corresponding calibration weight on the Platform the display flashes until the actual weight is registered an...

Страница 29: ...le division AC 2d 0 1 2 3 Levels FiL 1 Scale increment Sets the displayed scale increment also known as readability or graduation Selectable setup values will be model dependent and are equivalent to...

Страница 30: ...3 16 CHAPTER 3 SCALE TESTING AND CALIBRATION...

Страница 31: ...AC adapter Make sure the scale is off 2 Carefully lift and remove the Platform and Platform Support from the scale 3 Turn the scale over and remove the five screws which hold the Top Housing Refer to...

Страница 32: ...tions 1 Refer to Section 4 1 and remove Top Housing CAUTION Use care in the next step as the Display PCB wiring is attached to the PC board 2 Place the scale in the upright position and carefully lift...

Страница 33: ...h the hole in the Top Housing Peel off the protective film from the new Membrane Switch and carefully align and affix to the Top Housing 8 Press the Membrane Switch down uniformly Using your fingers w...

Страница 34: ...uitry and the Battery if the wiring is accidentally shorted during servicing Figure 4 5 Battery Terminal Connector Note the positioning of the cable for reassembly 3 Remove the screws and washers hold...

Страница 35: ...ing is installed in the correct locations 10 Connect the Display Cable to the Main PC Board connector See Figure 4 8 CAUTION THE DISPLAY CABLE CONNECTOR MUST BE CORRECTLY INSTALLED WITH THE TAB FACING...

Страница 36: ...and move the Main PC Board Jumper from normal to service position NORMAL SERVICE Figure 4 9 Main PC Board Jumper Positions 14 Position the Top Housing in place over the scale temporarily and install...

Страница 37: ...Switch Cable from the Display PC Board 3 Disconnect the Membrane Switch Cable from the Display PC Board See Figure 4 11 Figure 4 10 Disconnecting the Ribbon Cable 4 Remove the six screws that hold th...

Страница 38: ...damagesuchasacrackedglassorpartial display and the scale operates normally in all other functions NOTE This procedure is very difficult and should not be attempted unless you have the proper tools 1 P...

Страница 39: ...be checked before installation 1 Refer to Section 4 1 and remove Top Housing 2 Turn the scale over and remove the four feet by unscrewing them counter clockwise The feet are actually screwed into the...

Страница 40: ...n the slots on the Bottom Housing and secure with the screws and washers previously removed 12 Refer to Figure 4 15 and move the Main PC Board Jumper from normal to service position 4 4 REPLACING THE...

Страница 41: ...tery wires together with the Load Cell cable 3 Remove the Load Cell by unscrewing two bolts on the top of the Load Cell and two bolts on the bottom of the Load Cell See Figure 4 16 Figure 4 16 Load Ce...

Страница 42: ...sert the proper feeler gauge as specified in Table 4 2 2 With the correct feeler gauge positioned in the first Overload Protection Stop press down on the Frame and see if there is movement of the fram...

Страница 43: ...re is used when it is required to change the Battery WARNING DEATH OR SERIOUS INJURY CAN OCCUR Charge the battery only with the charger in the scale Charging the battery under any other conditions may...

Страница 44: ...e Top Housing is installed the Battery is held in place CAUTION Dispose of the Battery according to local regulations for hazardous materials Do not incinerate crush or throw out in regular garbage co...

Страница 45: ...t is made The scale MUST meet the parameters of all applicable specifications in this manual If further technical information is needed in the United States call toll free 1 800 526 0659 between 8 00...

Страница 46: ...HOUSING P N 80104205 EB SCALE FULLY ASSEMBLED TOP HOUSING OPEN MEMBRANE SWITCH P N 80251386 P N 80251391 EBJP DISPLAY PCB P N 80104191 FEET P N 80120032 1 Pc BOTTOM HOUSING P N 80120024 LCD P N 80104...

Страница 47: ...80104190 BOTTOM HOUSING OPEN Figure 5 2 Components in Bottom Housing of EB Series Scales BATTERY P N 80120026 DISPLAY CABLE P N 80120022 LOAD CELL TOP FRAME P N 80120039 POWER ON OFF SWITCH P N 80120...

Страница 48: ...20013 Loadcell EC3 80120014 Loadcell EC6 80120015 Loadcell EC15 80120016 Loadcell EC30 80120017 Loadcell assembly EC3 80120018 Loadcell assembly EC6 80120019 Loadcell assembly EC15 80120020 Loadcell a...

Страница 49: ...when either 0 0 or xx000 is displayed Notes 1 If the PCB has calibration data the display will indicate 0 0 When 0 0 is displayed proceed to paragraph A 2 Calibration 2 If a new PCB has been installed...

Страница 50: ...000 is displayed press COUNT button to step through the available settings for points of resolution as shown on table A 1 disregard any settings not shown in the table TABLE A 1 SCALE RESOLUTION SETTI...

Страница 51: ......

Страница 52: ...PN 80251392 A SERVICE MANUAL EB SERIES SCALES 80251392 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 TestEquipmentDepot com...

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