Keithley 175 Instruction Manual Download Page 44

Summary of Contents for 175

Page 1: ...uy your excess underutilized and idle equipment along with credit for buybacks and trade ins Custom engineering so your equipment works exactly as you specify Critical and expedited services Leasing R...

Page 2: ...Instruction Manual Model 175 Autoranging Multimeter 01983 Keithley Instruments Inc Cleveland Ohio U S A Document Number 175 901 01...

Page 3: ...SPECIFICATIONS...

Page 4: ...ontrols Input Terminals Current Fuse Replacement Error Messages Operating Conditions Environmental Conditions Maximum Allowable Input Basic Bench Measurements Power Up Relative Mode DC Voltage Measure...

Page 5: ...E Introduction Top Cover Removal Installation Batten Pack Model 1768 Installation Troubleshooting RecommendedTestEquipment SelfDiagnosticProgram PowerSupplyChecks AfDConverterandDisplay Signalconditio...

Page 6: ...Buffer Amplifier AIDConverter Resistance Measurements Ratiometric Technique Simplified Schematics of Ohms Circuitry Segment Identification CalibrationJumper Modell75ExplodedView Model 175 Display Asse...

Page 7: ...dings Equipment Specifications Limits for DC Voltage Verification Limits for AC Voltage Verification Limits for Resistance Verification Limits for DC Current Verification Recommended Troubleshooting E...

Page 8: ...test leads for possible wear cracks or breaks before each use If any defects are found replace with test leads that have the same measure of safety as those supplied with the instrument For optimum sa...

Page 9: ...gital Calibration l lOO Point Data Logger l 10 V 10mW10nA Sensitivity 0 03 Basic DCV Accuracy l TRMS AC l dBm Relative Functions l Min Max Reading Hold Safety Input Jacks lOA Capability l lOOkHz Speci...

Page 10: ...e AUTO annunciator D E F G H I Select DC volts by releasing outi the AC DC pushbutton V still selected The AC annunciator will turn off Select autoranging ohms by pressing in the pushbutton DC still s...

Page 11: ...with any DMM with at least IOM12 input impedance Accuracy f2OC from O to 100 C YC from 5Y to 0 C and 100 to 150 C Power 9V alkaline or C Zn NEDA 1604 battery Model 1600A High Voltage Probe Extends the...

Page 12: ...s i red l black two spade lugs two standard ba nana plugs two phone tips 060DIA two hooks and two mini Model 7008 IEEE 488 Digltal Cabl Useful for connecting the Model 1753 to the IEEE 488 bus The Mod...

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Page 14: ...the circuit using the installed connect disconnect device and make measurements without disconnecting the DMM 5 De energize the circuit using the installed connect disconnect device 6 Disconnect the...

Page 15: ...RCL flashes when buffer is full during logging cycle 2 4 2 Front Panel Controls ON OFF Pressing in this pushbutton turns the Model 175 on Releasing out this pushbutton turns the instrument off REL Re...

Page 16: ...ote that the instrument has a number of other massages that are discussed in the appropriate sections of this manual 2 6 OPERATING CONDITIONS 2 6 1 Environmental Conditions All measurements should be...

Page 17: ...t readings and displayed A REL level can be established for any measurement function Volts Ohms Amps and dB1 and is effective only on that function Changing functions will not affect a REL level alrea...

Page 18: ...or the best resolution 6 Take the reading from the display NOTE See paragraph 2 8 for TRMS considerations AC VOLTAGE Figure 2 3 TRMS AC Voltage Measurements 2 7 5 Resistance Measurements The Model 175...

Page 19: ...0 15 rdg per amp for self heating For currents between IOA and 20A specified accuracy can only be ob tained when measurements are limited to a max imum of 15 seconds 2 For current measurements up to 2...

Page 20: ...ay 2 dBm Measurements with Other Reference Impedances dBm measurements can be made with other reference imp pedances The most convenient method for using other reference impedances is to algebraically...

Page 21: ...log 6 Offset for B O log 1 Typical Instrument Performance Typically the Model 175 will perform better than its published dB specification The following example will il lustrate this point A Using the...

Page 22: ...oll on the display Release the RCL pushbutton at the desired data point and note the reading data on the display The data pointer can be incremented by steps of one by moman tarily holding in the RCL...

Page 23: ...ype meter reading The situation changes with the half wave rectified sine wave As before the peak value of the waveform is 1OV but the average value drops to 3 18V The RMS value of this waveform is 5...

Page 24: ...io of peak to RMS value will vary For example the crest factor of a rec 50 tang r pulse is related to its duty cycle as the duty cycle decreases the crest factor increases The Model 175 has a crest fa...

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Page 26: ...ne hour The instrument may be operated from either line power or battery pack power as long as the battery pack has been fully charged as described in paragraph 2 3 3 3 5 VERIFICATION PROCEDURE The fo...

Page 27: ...r 3 Press the REL pushbutton to compensate for the test lead resistance 4 Disconnect the short end connect the test leads to the calibrator 5 Set the calibrator to lOO OOOfl and verify that the readin...

Page 28: ...nals 6 Apply a current of 1 90000A to the Model 175 The reading must be within the limits specified in Table 3 5 3 5 5 AC Current Accuracv Check Since AC current uses the same circuitry as AC volts an...

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Page 30: ...stance ranges and 5 AC and DC current ranges A simplified block diagram of the Model 175 is shown in Figure 4 l The heart of the Model 175 is the AID converter that translates the conditioned analog i...

Page 31: ...These effects are minimized in the Model 175 through the use of software generated delays and by shorting the multiplexer bus to signal common before each signal measurement through Cllll 4 3 2 Input...

Page 32: ...100msec At the end of the charge balance phase the output of the integrator is resting at sc me positive voltage Since the integrator output is connected to the noninverting input of the UlOBA its ou...

Page 33: ...by the microprocessor through Ulll and U112 unknown resistance can be computed by the microprocessor using this equation Switching for the ohms ranges is done using low leakage base to collector diode...

Page 34: ...uring power up the microprocessor configures U201 to drive the triplexed display In order to drive the display correctly four voltages are obtained from R126 The clock required by U201 is obtained fro...

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Page 36: ...secure it to the shield using two supplied screws The screws are fed through the shield into the battery board fasteners Place the battery pack in the bracket and position if on lhe shield as shown F...

Page 37: ...the error per sists try replacing the NVRAM chip UllO Again the Model 175 must undergo a complete calibration after the problem is corrected Sequential Display Test Segments and annunciators are seque...

Page 38: ...2 15 3u5 Oul lul 2ul 3ul ou2 lu2 2u2 3 2 ou3 lu3 2 3 3u3 ou4 lu4 2 14 3u4 ou5 lu5 2 5 3u5 OAl OA6 lAl lA6 2A 2A6 3Al 3A6 AMP Gain IU105 I x10 x10 Xl Xl Xl Xl Xl Xl Xl Xl Xl Xl Xl Xl Xl Xl Xl Xl Xl Xl...

Page 39: ...vels on U114 LO PA0 PA 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 PA2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1...

Page 40: ...roperly seated on the mother board so that it will not touch the IEEE board if installed Table 5 4 A D Converter Checks step 1 Item Component 2 U123 pin 38 3 U122 pin 10 4 U122 pin 6 5 U122 pin 5 6 U1...

Page 41: ...f the instrument persistently blows fuses a problem may exist within the instrument If so the problem must be rectified before continuing operation 4 If the IEEE interface was installed reinstall by r...

Page 42: ...he top cover 1 Remove the top cover as explained in paragraph 5 2 2 The calibration jumper is located in the middle of the mother board right behind the shield Move the calibration jumper from positio...

Page 43: ...alibrator to output lOOn and adjust the display using the STO CLR and RCL buttons for a reading of 100 00f 5 Press the REL button and note that the REL annunciator turns off 6 Select the 2kR range and...

Page 44: ...constants after out appears on the display slide the calibration switch to ENABLED Press REL and dE 51 multaneously until CAL appears on the display Then sinwita eousiy press REL and dB until Star is...

Page 45: ...T 2000 CJG ITPIJT 724 F T OIUTPUT 717 i l i N WFIIT 5000 OCTPLIT 724 i Vi9X WAIT 3000 0 IQT P LlT 7 1 7 I S OIJTPIJT 724 z R4 C LEF R BEEP 50 1000 IISP 1 DISP blflRNING THE FOLLOWIN G STEPS USE HIGH V...

Page 46: ...utputs 190mV at 200Hz to 175 Calibrates high end of 2OOmV range Turns d9 annunciator on Outputs 19mV at 200Hz to 175 Calibrates low end of 200mV range Turns d9 annunciator off Sets 175 to 2V range Out...

Page 47: ...ai error output loon to 175 B 1000 from 51018 F Cal point plus lead resistance and cal error C Command that calibrates 175 using F Calibrate 2OOO range Loops to line 1250 once Sets 175 to Zkfl range S...

Page 48: ...MMENTS Outputs 1OOkfl to 175 Calibrates 200kll range Sets 175 to Mfl ranges Outputs lM0 to 175 Calibrates 2Mfl range outputs tom to 175 Calibrates 20MO range Stores calibration points in NVRAM S 13 61...

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Page 50: ...formation concerning replacement parts contact Your Keithley representative or the factory See the inside front cover for addresses When ordering include the following information 1 Instrument Model N...

Page 51: ...TOP COVER 176313 LINE CORD CURRENT FUSE CARRIER FH El XJM I 176314 FRONT PANEL 7 FEET 4 NOT SHOWN SOl rOM SHIELD 2YL CG FE 10 Figure 6 1 Model 176 Miscellaneous Parts 6 2...

Page 52: ...Figure6 Z Display 6 3...

Page 53: ...pacitor lpF 5OV Ceramic Film Capacitor lpF 5OV Ceramic Film Diode Silicon lN914 Rectifier REC40100 Diode Silicon IN5400 Bridge Rectifier VMl8 Socket 14 pin Connector Male 10 pin Relay High Voltage 5V...

Page 54: ...omposition Resistor 220 10 2W Composition Resistor 8 06k12 1 l EW Composition Resistor 1 24kfl I 1IEW Composition Thick Film Resistor Network Thick Film IOMn 1 4W Composition Thick Film 2 2k0 5 114W C...

Page 55: ...justable Regulator LM337L G2 2 E3 IC 345 U118 Triple 3 Input OR Gate CD4075BE SEV E3 IC 143 u119 Triple 3 Input NAND Gate MM74HClO SEV E4 IC 341 u120 Tri State Octal D Latch 74HC373 D5 2 E5 IC 338 u12...

Page 56: ...C Aluminum Electrolytic Rectifier Schottky Barrier 1N5620 Cable Assembly 10 Conductor Resistor 4 70 5 ll4W Composition Resistor 4 70 5 114W Composition Resistor 30 lk0 I l EW Metal Film Resistor 39 2k...

Page 57: ...3 FU 20 RL 62 RL 59 TG 62 TG 166 TG 138 TG 167 TG 128 RT 9 l IC 352 IC 347 IC 283 IC 353 IC 354 IC 351 IC 93 IC 345 DZ 58 DZ 72 1 Circuit Desig FlOl F102 KIOI K102 K103 0102 Q104 Q105 Q107 Q108 Q106 a...

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Page 60: ...1 2 4 I I I I F Figure 6 4 Model 1756 Battery Pack Component Location Drawing Dwg No 1756 100...

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Page 62: ...Figure 6 5 Mother Board Component Location Drswing Dwg No 175100 Page 1 of 21 6 13 6 14...

Page 63: ...113 J Figure 6 5 Mother Board Component Location Drawing Dwg No 175100 IPsge 2 of 21...

Page 64: ...1 2 3 i 4 t c 2 3 4 6 I I ci I Go I L1 I t I 0 I n Figure 6 6 Mother Board Schematic Drawng Dwg No 175106 Page 1 of 21 6 171618...

Page 65: ...I I I II Figure 6 6 Mother Board Schematic Drawing Dwg No 175 106 Page 2 of 21 6 19 6 20...

Page 66: ...CONTACT DESCRIPTION...

Page 67: ...X3 6 24...

Page 68: ...y or output circle one aDrifts q lJnable to zero q IJnstable q Will not read applied input q OverIoad q Calibration only q Data required UC of C required attachanyadditional sheetsasnecessary Show a b...

Page 69: ...uipment Have surplus equipment taking up shelf space We ll give it a new home Learn more Visit us at artisantg com for more info on price quotes drivers technical specifications manuals and documentat...

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