Sanwa PC20TK Instruction Manual For Assembling And Operation Download Page 1

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MULTIMETER

PC20TK

Assembling Training for
Digital Multimeter

Instruction Manual for Assembling and Operation Procedures

Summary of Contents for PC20TK

Page 1: ...MULTIMETER PC20TK Assembling Training for Digital Multimeter Instruction Manual for Assembling and Operation Procedures ...

Page 2: ...ng the fuse and batteries 11 2 8 Storage and others 11 3 Basic Knowledge of Digital Multimeter 3 1 Analog vs digital 12 3 2 Analog multitester AMT vs digital multimeter DMM 12 3 3 Construction of digital multimeter 13 3 4 Working of input signal conversion section 14 3 5 Working of A D conversion section 15 4 Assembling 4 1 Soldering 20 4 2 Soldering procedure 20 4 3 Precautionary instructions for...

Page 3: ...ous to the human body 3 Do not input any signal exceeding the maximum rated input value 4 Do not try to measure a line e g to a motor where induced voltage or surge voltage may occur because the maximum overload input value might be exceeded 5 Do not use the PC20TK if its main body or test lead is damaged or broken 6 Do not use the PC20TK with its case removed 7 Do not use any substitute for a fus...

Page 4: ... a test lead into it by mistake 5 If you connect the PC20TK to your PC by using the optionally available PC link software and PC link cable changes in electric quantity can be displayed as values or graphs on the PC monitor 2 2 Names of various parts Range Hold switch Function switch with power switch Hole for VDC adjustment DCV ADJ Panel LCD Select switch Data Hold switch Safety cover COM connect...

Page 5: ... may result in burning internal components About a battery at the time of the shipment There is a case that the battery does not reach mentioned battery life because a battery for monitors is incorporated at the time of factory shipment A battery for monitors is a battery to check a function and the performance of the product Mode Range Input resistance etc Accuracy Maximum overload protection inp...

Page 6: ...he true value therefore exists in the range of 106 6 V 2 1 V 104 5 to 108 7 V provided that it falls within the accuracy warranted temperature and humidity ranges and that for AC it is of sinusoidal AC within the range of 40 to 400 Hz If the true value does not fall within these ranges the reading on the PC20TK deviates from the standard 5 Sampling rate This is the number of times when an input an...

Page 7: ...lso displayed for any functional mode This indicates that the measured values are output as digital signals through the LED located on the rear of the PC20TK see 9 on page 10 The following explanation is made assuming that the auto mode is active When the mark appears on the upper right part of the readout the built in batteries have run out Replace the batteries Be sure to turn OFF the Function s...

Page 8: ...nput of 0 V a number equivalent to about 3 counts remains in the 4 VAC range but this is not a malfunction In the manual mode the 400 mV range may be selected but the accuracy is not warranted 1 Set the Function switch to V 2 Press the Select switch to display on the upper left part of the readout 3 Make the test pins contact with the object under measurement and then read the value displayed Fig ...

Page 9: ...single diode or transistor is acceptable Warning Making a test with voltage applied to the diode or transistor under measurement is not possible and such an attempt is dangerous Positive voltage is output at the measurement connector and the open circuit voltage 1 1 to 1 5 V the LCD shows RS232C OL V when the measurement connector is released Voltage drop in the forward direction of the diode beco...

Page 10: ...e object under measurement and check for continuity based on whether the buzzer sounds and the reading 400 Ω maximum 6 Measuring electric capacitance see Fig 2 6 This functional mode is mainly used to measure the electric capacitance of a capacitor Warning For safety ensure that the electric charge in the capacitor is discharged prior to measurement The electric capacitance measurement function is...

Page 11: ...the value displayed 8 Measuring AC current AC µA and AC mA µA and mA see Fig 2 8 This functional mode is used to measure sinusoidal AC current in a small transformer circuit or other Warning Be sure to measure current in series with the load An attempt to measure current in parallel with the load is dangerous as large current would flow through An error occurs if any current with non sinusoidal wa...

Page 12: ...n the rear of the PC20TK 2 Attach the cable box to the rear case of the PC20TK by using the screw provided with the cable box 3 Connect the cable connector to the PC 4 In using the PC20TK prop it against the stand Fig 2 9 An example of data displayed Fig 2 10 Connecting procedure Infrared LED light The digital signals output from the PC20TK is converted into infrared signals through the LED light ...

Page 13: ...r a long period of time store it with the built in batteries removed 4 The PC20TK is neither dust proof nor drip proof 5 The panel the rear case and others are made of plastics Therefore do not place them near any volatile solvent or heat source 6 Lightly wipe off dust and other foreign matter on the external surface of the PC20TK by using soft cloth 7 The readout LCD is made of glass Do not give ...

Page 14: ...nversion of the reading e g by multiplying it by 10 or 1 10 but allows the user to simply use the reading as it is with the corresponding unit A digital multimeter provides other useful capabilities such as holding data displaying the negative sign and warning an input overflow When popular models are compared between analog multitesters and digital multimeters there are no differences in size and...

Page 15: ...ut signals is selected using the Function switch all converted into DC voltage signals of less than several 100 mV through a voltage divider an electric shunt an AC DC converter rectifier or the like and then added to the input connector of the analog digital converter Fig 3 2 Block diagram of digital multimeter Fig 3 3 Input signal conversion section DC voltage analog quantity Input signal conver...

Page 16: ... 6 and then AC voltage ACV is converted into DC voltage DCV with a rectification circuit Fig 3 6 Measuring circuit for AC voltage ACV 3 DC current DCA and AC current ACA When current flows through a resistor voltage drop occurs in proportion to that current This means that current has been converted into voltage current voltage conversion For measurements of current such voltage is used Fig 3 7 sh...

Page 17: ...ction The A D conversion section converts DC voltage analog quantity that has been input from the input signal conversion section into a pulse number digital quantity in proportion to the intensity of that voltage The available A D conversion methods include the integration comparison and methods The PC20TK uses the method In this paragraph however the double integration method is explained becaus...

Page 18: ...1 t 1 t 2 Fig 3 10 Integration circuit Fig 3 11 Comparator AND gate When a digital signal H high electric potential is simultaneously applied to two input terminals a and b the output becomes H If either of the two input terminals is H and the other input terminal is L or if both terminals are L then the output becomes L Fig 3 12 AND gate circuit Control circuit This circuit consists of a logic ci...

Page 19: ...reverse integration point t3 in Fig 3 15 Hence 1 1 Vi T 1 Vref T2 0 CR CR When this equation is transformed into T2 Vi Vref T1 Vref and T1 are constants with known values This means that when T2 is found Vi can be calculated T2 is measured as a pulse number by the counter by converting it into the pulse number Since T2 has a proportional relationship with Vi it is finally displayed as the measured...

Page 20: ...d the time between points t2 and t3 is in proportion to the input signal Since two operations integration and reverse integration are performed this is called double integration 7 The comparator changes its output from a positive value to a negative one when the input voltage from the integration circuit becomes positive At the moment when the comparator s output changes from a positive value to a...

Page 21: ...ng signal Clock pulse Control circuit Double integration type A D converter Readout Counter Gate Integration circuit Comparator Output voltage Vo of integration circuit 0 voltage detection signal is generated Latch signal is generated Reset signal is generated Controller Input voltage Input voltage of integration circuit Output voltage of integration circuit Reverse integration period Integration ...

Page 22: ...emperature of a soldering iron that has no automatic temperature control use a voltage regulator or change the length of the exposed tip of the soldering iron In controlling the temperature with the length of the tip longer length of the exposed portion decreases the temperature while shorter one increases the temperature 3 If the tip of a soldering iron is dirty or coated with excessive solder so...

Page 23: ...he bottom is broken 4 If solder is not successfully absorbed with a solder absorber apply additional solder to that part and then try to absorb the increased solder Memo The time required to hold the soldering iron tip on the part to be soldered varies depending upon the size of the component to be mounted Use the time values shown in Figs 4 1 and 4 2 for reference only 4 4 Color codes and symbols...

Page 24: ...V 50 V 3 Identifying other components Fig 4 5 Example of identifying other components 4 Units Auxiliary units used for capacitors 1 F 106 µF 1000000 µF 1 µF 103 nF 1000 nF 1 nF 103 pF 1000 pF Auxiliary units used for resistors 1 MΩ 103 kΩ 1000 kΩ 1 kΩ 1000 Ω 1 mΩ 10 3 Ω 0 001 Ω Cathode mark Diode Mark showing the 1st pin I C 1st numeral Rated voltage symbol 1st numeral 2nd numeral Multiplier Toler...

Page 25: ... the removed screws M3 x 8 which will be used in the process described in 4 9 Remove the printed circuit board large by extending its pawls 4 Components mounted on paper board temporarily assembled components 5 Component in bag 6 Panel Fig 4 11 and components mounted on the panel Switch knob Brush mount 2 pieces of 2P brushes and 1 piece of 4P brush Spring arm with coil spring 7 Rear case Fig 4 16...

Page 26: ...reby melting the applied preliminary solder to solder the component the component will be secured 4 Solder the other end of land terminal by making the soldering iron tip contact with the other end of land terminal together with solder Fig 4 6 Take care to ensure that no short circuit occurs during soldering A D converter mounted After soldering cut off the lead wire of the quartz oscillator with ...

Page 27: ...omponent into the specified holes in the printed circuit board and then solder them on the opposite mounted surface Be sure to check the polarities of the buzzer No components other than the buzzer have polarities Fig 4 7 Part 1 After soldering cut off the protruding lead wire with a nipper 4 BZ Buzzer Be careful about polarities mark on positive side 5 R24 1 Ω R19 Thermistor 7 8 6 R36 10 MΩ Spark...

Page 28: ... your soldering work Fig 4 8 Part 2 Battery pad sponge of 55 x 30 mm Remove the backing sheet and then attach the pad COM Lead wire red 85 mm Battery terminal W Lead wire black 70 mm B Lead wire black 70 mm V Lead wire black 70 mm F Fuse Fuse folder Stopper A Lead wire red 43 mm 9 Battery terminal 2 pieces 10 Fuse folder 2 pieces 11 F Fuse 0 5 A 250 V 12 V Lead wire black 70 mm 13 W Lead wire blac...

Page 29: ...ective transparent film attached to the LCD surface do not remove the white film on the rear 2 Fit the LCD at an angle of about 30 degrees into the area surrounded by the LCD securing pawls located inside the panel 3 Once the lower part of the LCD is fit to the pawls lower the upper part stepped to place it horizontally on the panel Caution The LCD may be broken if excessive force is applied becau...

Page 30: ...heir threads Fig 4 14 10 After attaching circuit board to the front case fasten 3 points of the cables 11 Fasten 3 points of the cables V B and COM cable V and W B COM and W Refer page 26 Caution Bind cables as close as possible to their roots and cut extras Fig 4 15 12 Remove the backing sheet on the bottom of the dial and then attach the dial to the concavity in the panel Caution Before attachin...

Page 31: ...slot with the convexity at their respective leading ends at an angle of about 20 degrees left side in Fig 4 18 3 Open the stand and secure the rear case to the panel by using a screw of M3 x 22 right side in Fig 4 18 16 Dial A semitranslucent purple colored Warning label remove backing paper Battery terminal Dry cell Rounded side Round rubber foot Rear case Female thread 14 18 17 15 Through screw ...

Page 32: ...ade of screwdriver 2 3 in width x 0 4 0 5 mm in thickness shaft 4 2 mm max in diameter and 15 mm min in length 4 After the adjustment close the adjustment hole with the oval seal one seal is provided for spare use If a standard voltage generator with high accuracy is not available make connections as shown in 1 in Fig 5 1 and then make an adjustment by matching the reading on the PC20TK with that ...

Page 33: ...31 4 13 Layout of components on the mounting surface Fig 4 20 Layout of component on the mounting surface R38 or C15 ...

Page 34: ...C1 4 7u C3 0 022u C2 0 01u R5 40 2kD R15 22kF R16 22kF R0 18 7kF R2 22kF R7 91kF R4 20kD R37 84 5kD R38 1MF D4 TLN223 U1 LP3 VDD R6 100kD R10 10kD R12 510kD R3 10k C5 0 7u D1 LFB01LCT1 BZ Q1 2SD3601S GO TO LCD RS232C use only 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 OP2N NC OP20 ADIP NC ADIN NC SA SGND ADP DT NC SMV CRES1 RL NC RCAP ONEK NC TENK NC HUNK NC O...

Page 35: ...ttributable to a deviation as described in 4 12 Adjustments In rare cases the error of a circuit component is too large 5 1 Calibration procedure The PC20TK is typically calibrated by making connections as shown in Fig 5 1 matching the reading of the unit this multitester under test with the target value while changing the output from the generator and then reading the value displayed on the gener...

Page 36: ...53 376 0 384 0 mV DC 4 V 3 800 V 3 7752 V 0 66 3 760 3 840 V DC 40 V 38 00 V 37 732 V 0 71 37 60 38 40 V DC 400 V 380 0 V 378 21 V 0 47 376 0 384 0 V DC 750 V 600 V 594 1 V 1 00 592 608 V AC 4 V 3 800 V 3 8338 V 0 88 3 734 3 866 V AC 40 V AC 400 V 380 0 V 384 04 V 1 05 373 8 386 2 V AC 750 V DC 400 µA 380 0 µA 377 52 µA 0 66 374 1 385 9 µA DC 4000 µA DC 40 mA 38 00 mA 37 631 mA 0 98 37 41 38 59 mA...

Page 37: ...d by Functional mode range Reading M on PC20TK displayed value Reading T on standard true value Error rate Accuracy range DC 400 mV DC 4 V DC 40 V DC 400 V DC 750 V AC 4 V AC 40 V AC 400 V AC 750 V DC 400 µA DC 4000 µA DC 40 mA DC 400 mA AC 400 µA AC 4000 µA AC 40 mA AC 400 mA 40 nF 400 nF 4 µF 40 µF 100 µF Ω 400 Ω Ω 4 kΩ Ω 40 kΩ Ω 400 kΩ Ω 4 MΩ Ω 40 MΩ Cut here ...

Page 38: ...36 ...

Page 39: ...onnector is infinite 2 Circuit using an OP amplifier In Fig 6 2 when the input voltage is 500 V the output voltage is 0 5 V Find the value for R As one of the characteristics of the OP amplifier the resistance between a and b in Fig 6 2 is infinite but the electrical potential difference is 0 this is called imaginable short Fig 6 1 R kΩ 1 V V 990 kΩ MΩ R kΩ 500 V Vout i i hence 10 MΩ R Fig 6 2 990...

Page 40: ... Resistance measurement circuit Assume that the output voltage is 0 5 V when resistor Rx under measurement is connected to the input connector in Fig 6 4 Find the value for Rx See Fig 3 9 on page 15 Also find Rx when the output voltage is 0 2 V As explained in item 2 under 6 1 the resistance between a and b in Fig 6 4 is infinite but the electric potential difference is 0 Fig 6 3 Output voltage 40...

Page 41: ...was not successfully made because of R3 There is wrong wiring for COM or B or improper soldering The DCV adjustment was not successfully made because of R3 In particular there is wrong wiring for R19 PTC R22 36 GAP1 or GAP2 improper soldering or a short circuit The resistance value for 26 28 29 30 32 33 or 35 is incorrect or there is a short circuit In particular R17 R19 PTC R22 36 GAP1 or GAP2 is...

Page 42: ...nsure the safe transportation of the PC20TK place it in a box having volume of at least 5 times the product size and fill the space with sufficient pad or filler Mark the box as Product to be repaired Customer Service Section Hamura Factory Sanwa Electric Instrument Co Ltd 4 7 15 Shinmeidai Hamura City Tokyo 205 8604 Japan TEL 042 554 0113 FAX 042 555 9046 8 2 Repair fuses To place an order for fu...

Page 43: ... high heat like a soldering iron 3 Please do not leave this unit in any place where it will be exposed to direct sunlight high temperatures high humidity low temperatures or dew condensation 4 Please do not store this unit in any place where it will be exposed to too much vibration or in a place where it might fall and become damaged 5 Please remove the internal battery before storing the unit for...

Page 44: ... Instrument Co Ltd Head Office Dempa Building 2 4 4 Sotokanda Chiyoda ku Tokyo 101 0021 Japan Phone 81 3 3253 4871 Osaka Sales Office 2 7 2 Ebisu nishi Naniwa ku Osaka City 556 0003 Japan Phone 81 6 6631 7361 03 1308 2040 2040 ...

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