KERN HUM - FineMech
Contents
1. 12 3 5 2 Function Test for technicians only 13 4 TROUBLE SHOOTING nen ee 17 4 1 Trouble Shooting LOOP eue Sec es 17 4 2 Parts and Components Trouble Shooting 18 42 1 Power Supply Check un 18 4 2 1 1 Relevant Parts i v tao PH x op a ex odd 18 4 2 1 2 Input Voltage 5 5V or higher 19 4 2 1 3 Output Voltage of Regulation 5V 10 19 4 2 2 Load Receptor Check 19 4 2 3 LCD Display Check cidad 19 4 24 CPU cx 19 4 2 5 A D Unit Checking usa 20 5 ELECTRICAL CIRCUITRY 0 21 ASCHEMAUGS dotada 21 052 208 Layout 7 111111 11100 26 2 HUM SH e 0210 1 INTRODUCTION Features of the KERN HUM series Full Tare Tare indicator Zero indicator Negative value indicator Special hold function 2 types of calibration Dip switch to prevent end user calibration Built in rechargeable battery operated Operating time after fully charged 80 hrs Low battery signal AC adaptor included LED display Easy to read Optional Wireless Remote Controller Capacity 1ton 3ton 5ton 7 5ton 3 HUM SH e 0210 2 SPECIFICATION 1 SYSTEM BLOCK DIAGRAM 7 segment LED display GNE y LED Remote T driver IC Control urit E 0 j ge2. 13 HUM SH e 0210 DISPLAY SPAN VALUE FOR HUM1000k500 500kg or 1000kg HUM SH e 0210 14 15 HUM SH e 0210 Auto shut off when not in s 4 min eee 1 No Auto shut off 16 HUM SH e 0210 4 TROUBLE SHOOTING 1 TROUBLE SHOOTING LOOP DEN POWER ON DISPLAYS RANDOM NO DISPLAY FIGURES CHECK POWER SUPPLY CHECK CPU LCD CPU 7 SEG LED LCD PRIVER LCD K B OK 7 SEG LED A 04 011 5 SHOW 000000 COUNTS AND THEN ZERO CHECK LOADCELL OK A D UNIT OFFSET VALUE GHOST UNSTABLE PROPER READOUT CHECK POWER SUPPLY CHECK LOAD LCD LCD DRIVER RECEPTOR OADCELL R32 R35 CCS OK BAD SOLDERING CAN T REACH THE FULL INCORRECT CAPACITY CORRECT READOUT CHECK LOAD RE CALIBRATE RECEPTOR LOADCELL OFFSET VALUE THE SCALE 2 A NORMAL OPERATION 17 HUM SH e 0210 2 PARTS AND COMPONENTS TROUBLE SHOOTING 2 1 Power Supply Checking 2 11 Relevant parts HUM SERIES Power Board NCS 20 1 Q1 C1061 R1 1 2 ohm 1 2W Q2 C945 DC JACK SCD 21 B1 W041A Main Board NCS 11 2 U8 LM2930 5 Q2 A1515 C30 EC 10uF 16V Q3 C945 U9 HT 7039 ROCK SW R19 00 Tsv a Vearreny 18 HUM SH e 0210 Description 1 2 3 2 2 1 2 2 2 3 2 4 AC Adaptor This AC adaptor provides about 15V dc power Battery Bu
3. 26 HUM SH e 0210 NCS 11 2 TOP OVERLAY 6 NCS 11 2 BOTTOM OVERLAY 27 HUM SH e 0210 NCS 20 1 NCS 20 1
4. EPROM um E2PROM 5V Front KB Hore Battery ev 10Ah Els AC adaptor _ Board 1 RE un xm Description When load is applied to the loadcell the resistance to the excitation current in the strain gauge changes and the analog output signal varies It is amplified and digitalized continuously by the A D converter into a digital signal Subsequently the resulting count is processed and managed by the CPU The CPU refers to the instructions from the keyboard and then conveys the output data to the LCD driver which formats the data into a readout for the display 4 HUM SH e 0210 2 PHYSICAL LAYOUT OF ELECTRICAL CONNECTION eee LOAD CELL RECHARGEABLE BATTERY 8V tQAh ILL ZERO TARE MODE HOLD POWER 5 HUM SH e 0210 3 GENERAL SPECIFICATION 3 1 Overall View 500kg 2ton 3ton 6 HUM SH e 0210 7 5ton 3 2 Dimension Size 228 D x 210 W x 575 H mm 500kg 2ton capacities 228 D x 210 W x 609 H mm 3ton capacity 228 D x 210 W x 880 H mm 5ton 7 5ton capacities 3 3 Model Specification Display resolution 1 2000 1ton 1 2500 5ton 7 5ton 1 3000 3ton Internal resolution 1 30000 Display Single sided Weight display 5 digits 3 4 Operation condition Power source Rechargeable battery 6V 10 Ah or AC
5. 43 2K at 2000kg Trimmer HUM5000K2000 1 2500 4 7 10 16 at 2000kg 25 40 VR1 25K x at 5000kg Trimmer HUM7500K5000 1 2500 4 7 8 16 at 2000kg 20 30 at VR1 18K X 5000kg 30 45 at 7500kg Trimmer READING OFFSET VALUE 1 Turn scale off 2 Remove all load from platter 3 Enter F 3 and read the offset value READING SPAN VALUE Turn scale off Remove all load from platter Enter F 1 Press ZERO Apply load to platter Span value according to load applied will be displayed HOW TO ADJUST OFFSET VALUE In case the offset value is out of range adjust the trimmer located at VR1 TR2 on the mainboard to obtain correct offset value HOW TO ADJUST SPAN VALUE The span value is controlled by resistor located on R1A and R1B Standard resistor value of R1A and R1B is listed on the above table If the required span value is not attained then change R1A and or R1B resistor according to either case below Span value too low Increase the resistance of R1A and or R1B Span value too high Decrease the resistance of R1A and or R1B 11 HUM SH e 0210 5 FLOW CHART 5 1 Auto Calibration for end user START DISPLAY PRESS MODE POWER ON DISPLAY LOAD cua DISPLA Y TING NO CORRECT WEIGHT ASSIGNED DISPLAY no YES SPLAY DISPLA DONE 99999 DISPLAY DEN 99999 00000 DISPLAY 00000 DISPLAY q 12 HUM SH e 0210 5 2 Function Test for technicians only
6. KERN amp Sohn GmbH D 72322 Balingen Frommern Tel 0049 0 7433 9933 0 Postbox 4052 Fax 0049 0 7433 9933 149 E Mail info kern sohn de Internet www kern sohn de WAAGEN BALANCES WEIGHTS Service Manual Electronic Precision Balances Page 2 KERN HUM Version 1 0 1 HUM SH e 0210 s KERN HUM Version 1 0 Service Manual Electronic Precision Balances Table of Content T INTRODUCTION acess esses 3 2 SPECIFICATION 4 2 1 System Block Diagram sans 4 2 2 Physical Layout of Electrical Connection 5 2 3 General Specification erh lin 6 2 9 1 Overall VIEW 8 OO 6 2 9 2 DIMENSIONS ss al 7 2 3 3 Model Specification 7 2 3 4 Operating Conditions era 7 2 3 5 Main Components use 8 2 3 6 Analog Specification xcci E caben 8 2 3 7 Capacity amp DIVISION an aan aa re cde 8 3 INITIAL SETUP 1 1 9 3 1 Internal Functions and Alternate Division 9 3 2 Auto and Dealer Calibration 10 3 3 Disable Calibration with Dip Switch S1 10 3 4 Offset and Span Value Data 11 245 Flow Charm 3 7 12 3 5 1 Auto Calibration for end user
7. ZERO to save settings and return to normal operation 7 F 1 Span Value Reading and Dealer Calibration Simply enter F 1 then put on the designated mass to check Span Value or keep going to do Dealer Calibration F 2 Display Segment and Rated Capacity amp Division Check When function is entered scales will first display the rated capacity and division then display all segment Check and make sure that no segment are missed F 3 Check Offset Value is within acceptable range and Scale Configuration 1 Enter F 3 scale displays the Offset value 2 Hold MODE for about 2 seconds 3 Scale displays capacity and division configuration 4 Press MODE until the required configuration obtained Note In some countries only the metric weight unit is available Press ZERO to save setting and back to normal operation status e F 4 Auto Power Off Setting Two modes are available Default 4 OFF 0 OFF Auto Power Off function is disabled 4 OFF Scale will automatically turned off after 4 minutes unused 9 HUM SH e 0210 2 AUTO AND DEALER CALIBRATION ACCEPTABLE FOR AUTO AND DEALER CONFIGURATION Model Number External Acceptable Auto and Dealer Calibration Division Load HUM1000K500 1 2000 500kg 1000kg HUM3000K1000 1 3000 1000kg 2000kg HUM5000K2000 1 2500 2000kg 5000kg HUM7500K5000 1 2500 2000kg 5000kg Dealer Calibration Procedure Turn scale off Press a
8. adapter DC 15V 500mA Operating Temperature 0 C 40 C Operating Humidity 15 85 RH Power Consumption 1W 0 1W 5W When charge 7 HUM SH e 0210 3 5 Main Components used Micro Processor 89C51 80C31 Crystal Oscillator 6 MHz 7 3728MHz Display Device 7 Segments LED display Liquid Crystal Display LCD Loadcell 350 resistance loadcell 3 6 Analog Specification INPUT SENSIVITY 2mV V ZERO ADJUST RANGE 2 R O ZERO BALANCE RANGE 5 APPLIED VOLTAGE DC 5V SPEED OF A D CONVERSION 4 times sec INTERNAL RESOLUTION 30000 3 7 Capacity amp division MODEL NO CAPACITY EXTERNAL DIVISION HUM1000K500 1000kg 0 5kg HUM3000K1000 3000kg 1kg HUMS000K2000 5000kg 2kg HUM7500K5000 7500kg 5kg 8 HUM SH e 0210 3 INITIAL SETUP 1 INTERNAL FUNCTIONS AND ALTERNATE DIVISION INTERNAL FUNCTION TABLE Function Symbol Description 1 Span value reading and dealer calibration 2 F2 Full display segment and max capacity check 3 F 3 Check offset value and scale configuration 4 F 4 Auto power off setting HOW TO ENTER THE REQUIRED FUNCTION MODE Turn scale off Press and hold TARE then turn scale on Scale display F 1 Press TARE until the required function number appears Press MODE Press MODE until the required setting appears Press TARE to confirm Repeat step c to f for other function setting or Press
9. d and connected properly between LCD and driver IC uPD 7225 and CPU 2 3 2 Check whether LCD is broken CPU Checking 2 4 1 Check that all pins are seated properly into the socket 2 4 2 Check that the Crystal Oscillator works 2 4 3 Check the RESET is normally low 19 HUM SH e 0210 2 5 A D Unit Checking 2 5 1 Check that the 5V power is correctly fed to the A D unit 2 5 2 Check that the signal output of loadcell is normal 2 5 3 Check OP Amplifier amp A D Converter AD7715 When no error is found with the above checking procedures the trouble can be caused on the loadcell or the PCB itself Replace a new one could be better to identify the defective In this way the readout of weight would be varied because of the output voltage of loadcell and different span value so recalibration is required after this replacement 20 HUM SH e 0210 5 ELECTRICAL CIRCUITRY 1 SCHEMATICS HUM series 8 2 2 5 21 HUM SH e 0210 on 5 0 9510 2D HUM SH e 0210 HUM SH e 0210 23 5 4 LO BAT Title CRANE SCALE DC POWER Drawn by JUNG HUM SH e 0210 24 1 NCS CHARGING BOARD el wes 29 T 17 1598 1997 I 07 3 Files CHei i 1 1 lrawn Bur BEN LE HUM SH e 0210 25 2 PCB LAYOUT
10. ilt in Rechargeable Battery 6V 10 Ah How Battery is charged completely The charging voltage is regulated by Q1 C1061 and ZD1 7 5V for about 7volts The charging current will go down automatically If battery s voltage reached Q2 C945 and R1 1 2R 1 2W provide Over Current protection Charging status indications LED turns RED or ORANGE colour In charged LED turns GREEN colour gt Full charged Auto off If the scale is set on 4_ Off or even under LO BAT situation after some minutes the CPU will release a negative pulse to cut off Q4 transistor then Q1 will be cut off too therefore the scale is shut down immediately Low Power Detection The U9 HT 7039 is designed to detect the power level Whenever the power less than 5 4 V it will release a low potential signal to CPU and then CPU will instruct display to show LO BAT symbol 2 Input voltage 5 5V or higher Check and recharge battery if voltage less than 5 5V Check and replace DC Jack or AC adaptor if been defective 3 Output voltage of regulation 5V 10 Check that the output voltage is within 5V 10 a less than 2 7V the CPU may not work properly b more than 6V ghost will appear on LCD Load receptor Checking The load receptor device shall not touch anything around itself during operation Check that the load receptor is not contacted with the upper no load and or lower with load stopper LCD Display Checking 2 3 1 Check that it is soldere
11. nd hold TARE then turn scale on Scale displays F 1 Press MODE Scale displays offset value Press ZERO to zero offset value Press TARE Press ZERO Press TARE 0 Press ZERO the LED bellows ZERO indicator will be lighted It means the scale is ready for dealer calibration 11 Make sure that the figure being displayed is 0 or 1 if not press ZERO again 12 Load calibration either load as listed on above table 13 When value display is stable press MODE 14 Wait until the scale start count down 15 Calibration completed and scale is ready for operation SPAN ANS Auto Calibration Procedure Turn scale off Press and hold MODE then turn scale on Scale displays CAL Press MODE Scale displays LOAD XXXX or XXXX Load calibration load according to above table Wait until the scale display DONE and start count down Calibration completed and scale is ready for operation o O a 3 DISABLE CALIBRATION WITH DIP SW S1 The DIP SW 1 is used to control calibration Push this switch to ON position to disable calibration 10 HUM SH e 0210 4 OFFSET AND SPAN VALUE DATA OFFSET AND SPAN VALUE DATA TABLE Model Number External Offset Span Value Thousand at Offset Span Division Value Various Load Applied Control Control Ohm Thousand RIA R1B HUM1000K500 1 2000 4 7 10 16 at 500kg 25 40 at 1 40k x 1000 kg Trimmer HUM3000K1000 1 3000 4 7 10 15 at 1000kg 20 30 VR1
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