EMB Version 3.3
Contents
1. EMB 200 2 EMB 600 2 EMB 220 1 EMB 500 1 weight tol weight tol weight tol weight tol 9 9 9 9 9 9 9 9 50 00 0 02 100 00 0 02 50 0 0 2 100 0 0 3 100 00 0 02 200 00 0 02 100 0 0 2 300 0 0 3 150 00 0 02 400 00 0 04 150 0 0 2 500 0 0 3 200 00 0 02 600 00 0 06 200 0 0 2 1200 1 2200 0 5 2 1 5 2 5 weight tol weight tol weight tol weight tol 9 9 9 9 9 9 9 9 200 0 0 3 500 2 1000 3 1000 10 500 0 0 3 1000 2 3000 3 3000 10 1000 0 0 3 1500 2 5000 3 5000 10 1200 0 0 3 2000 2 EMB 100 3 EMB 1000 2 weight tol weight tol 9 9 9 9 10 000 0 002 100 00 0 02 20 000 0 002 200 00 0 02 50 000 0 003 500 00 0 03 70 000 0 003 700 00 0 03 100 000 0 003 1000 00 0 03 6 Check other functions such as Tare and Auto Off 10 EMB SH e 0933 9 Replace Load Cell Assembly 1 Disassemble top housing of scale 2 Disconnect the load cell wires from main PCB Remove the screws fixing the bottom plate of the load cell assembly Replace the load cell with a new one Connect the load cell wires and fix the screws 3 Perform internal calibration as described in section 4 4 Assemble the top housing 5 Check accuracy of scale at different weight EMB 200 2 EMB 600 2 EMB 220 1 EMB 500 1 weigh2. KERN amp Sohn GmbH WAAGEN GEWICHTE BALANCES WEIGHTS Ziegelei 1 Tel 49 0 7433 9933 0 D 72336 Balingen Fax 49 1017433 9933 149 E Mail info kern sohn com Internet www kern sohn com Service manual School balance KERN EMB Version 3 3 4 2009 GB EMB SH e 0933 KERN Version 3 3 4 2009 Service manual School balance Table of Contents Basic Information Features 1 2 ____ 3 Calibration Procedure CAL 4 Internal Calibration Procedure Linearity Adjustment 4 1 Readout of the Internal Counts 5 Display Segment Test 6 Functional Block Diagram Description 6 1 Functional Block Diagram 6 2 Function Description 7 Trouble Shooting 8 Replace PCB 9 To Replace Load Cell Assembly 10 Schematics 10 1 For EMB 220 1 EMB 2200 0 EMB 5 2K5 10 2 For EMB 500 1 EMB 1200 1 EMB 5 2K1 10 3 For EMB 200 2 EMB 600 2 10 4 For EMB 100 3 EMB 1000 2 11 Components Layout 11 1 For EMB 220 1 2200 0 5 2K5 11 22 For EMB 500 1 EMB 1200 1 5 2 1 11 3 For EMB 200 2 600 2 114 For EMB 100 3 EMB 1000 2 DOD 0 4 4 NN A BP ONN 5 0933 1 Basic Information Grundlegende Hinweise The device must be repaired only by trained specialist staff or personnel with professional formation such as a repair specialist accredited by law concerning verification The service manual
3. Repeat step 5 for other calibration weights until display show then off Remove all weights from weighing pan Disconnect the pads below J1 for EMB 220 1 EMB 2200 0 EMB 5 2K5 43 for EMB 100 3 EMB 500 1 EMB 1000 2 EMB 1200 1 5 2 1 J9 for EMB 200 2 EMB 600 2 Turn scale on and check the accuracy at different weight Install the top housing of scale In case E is display instead of this indicates calibration procedure error or wrong weight applied for calibration Turn the scale off and then on and repeat the procedure EMB SH e 0933 4 1 Readout of the Internal Counts For example Without number In that case the internal count is 66 063 With number here 3 You have to set this number before the value In that case the internal count is 321 580 5 Display Segment Test Whenever the scale is power on all segments of the LCD will be turn on for approx 5 seconds Check for any missing segment 6 EMB SH e 0933 6 Functional Block Diagram Description 6 1 Functional Block Diagram Keyboard 9V 2xAA Battery Power control or Regulator amp Microprocessor Adaptor Low battery detector Load cell A D Converter Sensor EMB SH e 0933 7 6 2 Function Description 1 Load cell This is the heart of the whole system The load cell itself is arranged as a bridge The resistance change of the bridge elements is proportional to the load applied on the load cell The
4. 10 4 For 100 3 EMB 1000 2 Tweet 3939882 48422131 4 za gal 1388899 805801 5 EN EMB SH e 0933 15 R10 100K 1 R31 GND SND L al R34 2 25 21 26 3 3V sour GND 5V GND ie aa 3 3 7 R35 100K A 22 iL C23 hour Tuur 624 034 5 AGNO pe AGHD AGND a IT ow v 177 AW R11100K 1 056 849 200K 1 825 100 1 Rie R20 CIS 0 01nF 1 30K 1 Inf 4 SD R21 200k 1x GND mems SD cis St as 10 M CAP R22 mams w 1 RI2AM 1 Ft 0 R23 dij 27 2 100 22 22pF AGND SCHEMATIC EMB SH e 0933 16 11 Components Layout 11 1 EMB 220 1 EMB 2200 0 EMB 5 2 5 5052 091405 6 O O O O ire 3 REV O 03 01234567890 R24 022 R26 Em E EB H 0 vD TOOK 100 041 551 CND 22013 AUF R29 R28 827 ss 5 Ea nd EA i kol 250K 24 es 14 5 0
5. 933 17 11 2 For 500 1 EMB 1200 1 5 2 1 57 22304 99 R19 y Jy Je 10 tour 123155785 gt 1 x cu 0 17 781 05 11 3 200 2 600 2 4MHz 5 EN4401 5 VL2 R34 te 2 440 402 244403 2 075 KSS7P2316 819 RIB RELIES 5052 091405 000 REV O DO 0123456789 uf u3 I 0 00 R46 25 1623 87 RI 0 002242 R44 18 5 0933 11 4 For 100 3 1000 2 g 0 5 5 LAYOUT 00091 5052 0914108002 REVISIONS DESCRIPTION EMB SH e 0933 19 REVISIONS ZONE REV DESCRIPTION DATE APPROVED 201 1234567890 942 26 PART NO 5052 03211 000 EMB SH e 0933 20
6. dure error unstable or wrong calibration weight applied for calibration Turn the scale off and then on and repeat the procedure 4 EMB SH e 0933 4 Internal Calibration Procedure Linearity Adjustment 1 2 Remove top housing of the scale Connect the pads below together by soldering J1 for EMB 220 1 EMB 2200 0 EMB 5 2K5 J3 for EMB 100 3 EMB 500 1 EMB 1000 2 EMB 1200 1 EMB 5 2 1 J9 for EMB 200 2 EMB 600 2 Place scale on a hard level surface With weighing pan installed turn scale on Display shall show the internal counts The internal counts shall fall in the range from 3 000 to 5 000 For EMB 200 2 and EMB 600 2 the internal counts shall fall in the range from 50 000 to 80 000 For EMB 100 3 and EMB 1000 2 the internal counts shall fall in the range from 100 000 to 300 000 In case out of this range connect J9 J4 for EMB 200 2 and EMB 600 2 J6 for EMB 100 3 and EMB 1000 2 left side or right side to increase or reduce the reading Connecting or disconnecting pads on J6 J7 or J8 for EMB 220 1 EMB 2200 0 EMB 5 2K5 45 J6 47 or 48 for EMB 500 1 EMB 1200 1 EMB 5 2 1 J1 J2 or J3 for EMB 200 2 EMB 600 2 J2 J3 J4 or J5 for EMB 100 3 EMB 1000 2 can fine tune the reading Press OFF key once Display will show the required calibration weight Place the corresponding calibration weight on the center of the weighing pan Press OFF key while the weight is placed on the weighing pan
7. is obligatory for repair work After repair original conditions of the device have to be restored Only original spare parts should be used Das Gerat darf nur von geschultem oder beruflich ausgebildetem Fachpersonal z B eichrechtlich anerkannter Instandsetzer repariert werden Die Serviceanleitung ist bindend fur Reparaturen Das muss nach erfolgter Reparatur wieder in den Originalzustand zur ckversetzt werden Es d rfen nur Originalersatzteile verwendet werden Features Auto zero Full Tare function 4 weighing units Display segment test function Negative value indication Auto off function battery mode only enable disable Zero tracking enable disable Two types of Digital Auto Calibration Solder pads to prevent end user internal calibration Low battery indicator Overload protection indication AC adaptable Operated by 2 x AA size alkaline batteries EMB220 1 EMB2200 0 5 2 5 9V battery EMB100 3 EMB200 2 EMB600 2 EMB1000 2 EMB500 1 EMB1200 1 5 2 1 5 0933 3 3 Calibration Procedure CAL 1 Turn scale on by pressing the ON TARE key 2 Press the OFF key for approx 5 seconds Display will show CAL and then the required calibration weight 3 Gently place the correct calibration weight on the center on the weighing pan Wait until display shows then turn off In case is display instead of F this indicates a calibration proce
8. o display check battery adaptor keys connection between battery adaptor main board If missing segments check fixing of LCD frame zebra connector under LCD 2 If display LO check battery gt 2 gt 7 5v for EMB 100 3 EMB 200 2 EMB 600 2 EMB 500 1 EMB 1000 2 1200 1 EMB 5 2 1 adaptor gt 9v If display E check internal count Proper readout If unstable reading check weighing plate overload stopper load cell and wires environmental conditions and stable table 4 Correct reading If not accurate perform internal calibration If cannot reach full capacity check weighing plate overload stopper load cell and internal zero point If always zero check internal zero point Internal calibration if necessary 4 Normal operation EMB SH e 0933 9 8 Replace PCB 1 Disassemble top housing of scale 2 Disconnect PL1 SS1 and flat line of keyboard EMB 220 1 EMB 2200 0 EMB 5 2K5 PL1 PL2 and PL3 EMB 500 1 EMB 1200 1 EMB 5 2 1 PL1 PL2 and JP1 200 2 600 2 PL1 JP2 J1 flat line and SENSOR 100 3 1000 2 from the PCB Disassemble the PCB screw Replace a new PCB Assemble the PCB screw and connect the cables and the flat line again 3 Perform internal calibration as described in section 4 4 Assemble the top housing 5 Check accuracy of scale at different weight
9. refore the output of the load cell is an analog signal which is proportional to the load applied on the scale 2 Amplifier The analog signal from the load cell is very small of the order of micro volt Hence a linear and stable amplifier is applied to amplify the analog signal to an appropriate level 3 A D Converter In order for the analog signal can be input to the microprocessor this part converts the analog signal to its digital equivalent The operation of the analog to digital converter is using a SIGMA DELTA technique and under the control of the microprocessor 4 Microprocessor The microprocessor control all the functions of the scale such as auto zero A D conversion timings weight calculation display overload indication low battery indication tare function etc 5 Display This is the part where the weight is shown out on the LCD display in digital form The whole display is driven by the microprocessor 6 Power Regulator and Low Battery Detector This part contains the ON OFF power control In order for the external power can be used by other parts of the scale a regulator is used to regulate the supply A low battery detector is employed to make sure that the power supply is strong enough for normal operation of the scale 7 Keyboard The keyboard provides on user interface On TARE OFF keys are employed to operate the scale 8 EMB SH e 0933 7 Trouble Shooting Power on 4 Full Segments If n
10. t tol weight tol weight tol weight tol 9 9 9 9 9 9 9 9 50 00 0 02 100 00 0 02 50 0 0 2 100 0 0 3 100 00 0 02 200 00 0 02 100 0 0 2 300 0 0 3 150 00 0 02 400 00 0 04 150 0 0 2 500 0 0 3 200 00 0 02 600 00 0 06 200 0 0 2 1200 1 2200 0 5 2 1 5 2 5 weight tol weight tol weight tol weight tol 9 9 9 9 9 9 9 9 200 0 0 3 500 2 1000 3 1000 10 500 0 0 3 1000 2 3000 3 3000 10 1000 0 0 3 1500 2 5000 3 5000 10 1200 0 0 3 2000 2 EMB 100 3 EMB 1000 2 weight tol weight tol 9 9 9 9 10 000 0 002 100 00 0 02 20 000 0 002 200 00 0 02 50 000 0 003 500 00 0 03 70 000 0 003 700 00 0 03 100 000 0 003 1000 00 0 03 5 0933 6 Check other functions such as Tare and Auto Off 10 Schematics 2 5 10 1 220 1 2200 0 5 OILVA3HOS 7 onze YY 508 a gt 2427 199 5 0 8 1031 c 9 2 Mrt 14 OW or 1124 423 2 Wr gt r ono ze mI 3 3 955343 5 0933 12 10 2 500 1 1200 1 5 2 1 SCHEMATIC REVISIONS 3 5 5 EMB SH e 0933 13 10 3 200 2 600 2 7 7 5 17294405 Ucar 14 EMB SH e 0933
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