KEI 602 Instruction 电路图.pdf
MODEL 602 INSTRUCTION MANUAL Instruction Manual Model 602 Solid-State Electrometer Publication Date: June 1963 Document Number: 29111 Rev. C Contains Operating and Servicing Information for the Model 602 Solid-State Electrometer 01975, Keithley Instruments, Inc. Cleveland, Ohio, U.S.A. Document Number 29111 RadioFans.CN 收音机爱 好者资料库 WARRANTY Keithley Instruments. Inc. warrants this product to be free from defects in material and workmanship for a period of 1 year from date of shipment. Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable batteries, diskettes, and documentation. During the warranty period, we will, at our option, either repair or replace any product that proves to be defective. To exercise this warranty, write or call your local Keithley representative, or contact Keithley headquarters in Cleveland, Ohio. You will be given prompt assistance and return instructions. Send the product, transportation prepaid, to the indicated service facility. Repairs will be made and the product returned, transportation prepaid. Repaired or replaced products we warranted for the balance of the origi- nal warranty period, or at least 90 days. LIMITATION OF WARRANTY This warranty does not apply to defects resulting from pmduct modification without Keithleys express written consent, or misuse of any product or part. This warranty also does not apply to fuses, software, non-rechargeable batteries, damage from battery leakage, or problems arising from normal wear or failure to follow instructions. THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE REMEDIES PROVIDED HEREIN ARE BUYERS SOLE AND EXCLUSIVE REMEDIES. NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT, INDI- RECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON, OR DAMAGE TO PROPERTY. Keithley Instruments, Inc. - 28775 Aurora Road * Cleveland, OH 44139 * 216-248-0400 *Fax: 216-248-6168 * RadioFans.CN 收音机爱 好者资料库 SPECIFICATIONS AS A VOLTMETER: RANGE: .OOlV full scale to 1OV in ninelX and 3X ranges. ACCURACY: f 1% of full scale on all ranges exclusive of noise and drii. ZERO DRIFT: Less than Im” per 24 hours, Ikss than 150 per OC. METER NOISE: *25 *t4% of full scale on 3 x lo-l2 fo 10-14A ranoes. METER NOISE: Less than f3 x 10-16A. OFFSET CVRRENT: Lens than 5 x 10-15A. AS AN OHMMETER: RANQE: 7000, full scale to 10% in twent+hree linear IX and 3X ranges. ACCURACY: *3% of full scale on 100 to lQ ranges using the largest available multiplier stting; f5% of full scale on 3 x 109 to 1Ojn ranges. AS AN COULOMBMETER: RANGE: lo-? full scale to 10dC in fifteen IX and 3X ranges. ACCURACY: f5% of full scale on all ranges. Dritt due fo offset current does no, exceed 5 x 10.=C per second. AS AN AMPLIFIER: tNPUT IMPEDANCE: Greater than 1040 shunted by2OpF. input resistance may a,so be nanual. 1. The Model 602 has excellent zero stability which permits The symbol # on the instrument indicates that a po- accurate measurements with minimal adjustment. Short tential of 1OOOV or more may be present on the terminaltsl. term zero drift is less than 50he NOTE terminal voltage. If the leakage current is less than the offset current (less than 5 X 10.5A there may be no decay of the Using the center zero scales decreases accuracy terminal voltage when the Model 602 is left connected across 0.5% because the scale span is reduced. the capacitors terminals. 2. After a few moments increase the voltage sensitivity by NOTE Keep the shield cap on the INPUT connector when the Model 602 is not in use. advancing the multiplier switch. Continue zeroing with the FINE ZERO control. 3. After long periods of storage or after an overload, the Model 602 may drift excessively. The input transistors are The Model 6012 Triaxial-to-Coaxial Adapter permits use of cables and accessories with the Model 602 by adapting the triaxial INPUT connector to the UHF coaxial type. insensitive to mechanical shock; however, a severe input overload may cause a zero offset. This is corrected with the ZERO controls. Drifting can occur for several hours. NOTE CAUTION The Model 6012 connects low to case ground. The Modal 602 cannot be used off- ground when using the Model 6012. The in- struments cabinet will be at the same If the Model 602 has been stored for some time, the offset current will exceed the specification when first used, then decrease to below the specified amount after one or two hours of use. This is an inherent characteristic of the input transistors; the instrument is not faulty. potential as the input low. 4. Although the offset current of the Model 602 is below that 2.5 PRELIMINARY PROCEDURES found in conventional voltmeters, it can be observed on the meter. The current charges the input capacitance, and Check battery condition by holding the METER switch in the the Model 602 appears to drift when the input is open. Use BATTERY CHECK position. Rotate the multiplier switch the ZERO CHECK button to discharge the charge build-up. through the ,001 to 0.1 positions and observe the meter Depressing the ZERO CHECK button removes all signal readings. The meter should read at least two-thirds of full from the amplifier and reduces the input impedance scale in each multiplier switch position. Table 2-2 shows the between HI and LO terminals of the INPUT connector to 10MR. 2-l 5. Follow the procedures in paragraphs 2.6 to 2.10 for measuring voltage, current, resistance and charge. NOTE When using multiplier switch settings of 10, 3 and 1 in the voltage, current, resistance and charge measuring modes, make sure the OUT- PUT switch is set to 1V if the output is con- nected to a load of more than 2kR. Otherwise, the meter will not read full scale signals correct- ly. When the output is loaded, this effect is not present. 2.6 VOLTAGE MEASUREMENTS The Model 602 can be used to measure voltages. In the nor- mal method (FEEDBACK switch at NORMAL) the unknown voltage is connected to the INPUT connector. Input im- pedance with the range switch in the VOLTS position is 10%. 2OpF. To reduce the effects of input cable capacity, use the fast method to measure the voltage. Set the FEEDBACK switch at FAST and drive the inner shield of the cable with the Xl OUTPUT which is connected to the LO terminal in the FAST position, A guarded circuit is possible this way. To reduce stray pick-up when making routine measurements fix. measuring from low impedance sources1 the range resistors or capacitors may be used to shunt the input. Accessory probes extend the Model 602s range to 1OkV. NOTE Locking the ZERO CHECK switch places 1OMB between input high and low, which may tem- porarily cause instability in e.ome types of high impedance sources. 2.6.1 Normal Method Voltage Measurements Set the controls as follows: ZERO CHECK Button LOCK Range Switch VOLTS Multiplier Switch 10 FEEDBACK Switch NORMAL METER Switch CENTER ZERO Connect the unknown voltage to the high (center) terminal of the INPUT connector and to the OHMS GUARD terminal on the rear panel. Use the LO terminal as a guard between circuit high and low. Unlock the ZERO CHECK button. Set the mater switch to + or -, as necessary. Increase sensitivity with the multiplier switch. Recheck zero setting after increasing sensitivity. To make off-ground voltage measurements, see paragraph 2.7. 2.6.2 Guard Method Voltage Measurement Set the controls as follows: ZERO CHECK Button LOCK Range Switch VOLTS Multiplier Switch 10 FEEDBACK Switch FAST METER Switch CENTER ZERO Connect the unknown voltage to the high (center) terminal of the INPUT connector and to the OHMS GUARD terminal on the rear panel. Use the LO terminal as a guard between circuit high and low. Unlock the ZERO CHECK button. Set the METER switch to + or -, as necessary. Recheck zero setting after increasing sensitivity. To make off-ground voltage measurements, see paragraph 2.7. 2.6.3 Low Impedance Sources To decrease input resistance, set the FEEDBACK switch to NORMAL and the range switch to one of the AMPERES ranges. The input resistance is now the reciprocal of the cur- rent range. For instance, to obtain an input resistance of lo%, set the range switch to the 10.rA range Set the full scale voltage range with the multiplier switch. Operating pro- cedures are the same as paragraph 2.6.1. With reduced input resistance, the Model 602 will not be deflected off scale by stray fields when the input is left open. 2.7 OFF-GROUND VOLTAGE MEASUREMENTS The Model 602 can measure an unknown voltage whose low impedance terminal is up to 1500V off-ground. Safe opera- tion of the Model 602 is ensured by grounding the case (see paragraph 2.6). CAUTION Operating the Model 602 more than 16OOV off-ground may permanently damage the instrument. Isolation between circuit low and ground may break down somewhere in the instrument. Since these breakdowns are very difficult to locate, it might not be possible to float the instrument safely again. 2.7.1 FEEDBACK Switch Set To NORMAL Disconnect the shorting link between LO and CASE GROUND terminals on the rear panel. Make sure the Model 602 case is securely connected to an earth ground, and that the low of the unknown voltage is less than 1500V off- ground. Connect the unknown voltage directly to the INPUT connector. Operate the Model 602 as described for normal method voltage measurements. 2.7.2 FEEDBACK Switch Set To FAST This method reduces the effects of input cable capacity with Disconnect the shorting link between the LO and CASE very high impedance source.s and allows guarded voltage GROUND terminals on the rear panel. Make sure the Model measurements. 602 case is securely connected to an earth ground, and that 2-5 the low of the unknown voltage is less than 1500V off- ground. Connect the high of the unknown voltage to the center terminal of the INPUT connector. Connect the low to the OHMS GUARD terminal. Use the LO terminal or inner shield of the INPUT connector as a guard. Operate the Model 602 as described for fast method voltage measurements. WARNING If the output is used for recording when the Model 602 is off-ground in the normal or fast mode, make sure the shell of a mating plug to the OUTPUT connector is not con- nected to either pin in the connector. Also. the recorder output will be off-ground. WARNING Use only an insulated blade screwdriver to adjust the COARSE ZERO switch and 1 MA CAL control when floating the Model 602. An ordinary screwdriver could short the cir- cuit low to case ground, creating a shock hazard and damaging the external circuitry. 2.8 CURRENT MEASUREMENTS The Model 602 can measure current three ways. 1. In the normal method luseable on any range) the current is determined by measuring the voltage drop across a resistor shunting the amplifier input. This method is useful when low noise is more important than fast response speed or if some damping is needed. 2. In the fast method (for use only below the lC-5A range) the shunt resistor is between the amplifier output and input in the feedback loop. This circuit largely neutralizes the ef- fect of input capacity and greatly increases the response speed. Also, the input voltage drop is reduced to a maxi- mum of 1mV on any range. 3. For galvanometric current measurements, the Model 602 acts as a null indicator between a known current and the unknown current source. Rise time varies primarily with the current range, the input capacity and the method used. Wifh the FEEDBACK switch in the FAST position, the rise time on the most sensitive range is less than 2sec and on the lA range, less than 3msec. Given a choice, it is better to place the Model 602 nearer to the current source than fo the data reading instru- ment. Transmining the input signal through long cables slightly decreases the response speed and greatly increases noise due to cable capacitance. To measure from a source with both terminals off-ground in either method, remove the link between the LO and CASE GROUND terminals on the rear panel. Connect the unknown current fo the INPUT connector. The source must be less than the input will increase up to 1OV due to its constant current characteristic. Keep the input shorted or the ZERO CHECK button lock- ed. The full scale ohms range is the multiplier switch times the range switch sening. Use the smallest range switch setting possible to obtain the best accuracy. Before making a final reading, manipulate the multiplier and range switches so the sample is tested at a number of teat potentials. The applied test voltage is the percentage of full scale that the meter reads times the multiplier switch setting. 2-7 When the test current is applied, the high terminal of the INPUT connector is positive. The test current is the reciprocal of the OHMS range setting. NOTE Shield the input if the resistance sample exceeds 10%. 2.9:2 Fast Constant Currant Method Follow the instructions of paragraph 2.5. Set the controls as follows: ZERO CHECK Button LOCK Range Switch 10” OHMS Multiplier Switch 1 FEEDBACK Switch FAST METER Switch + Connect the high impedance side of the resistance sample to the center terminal of the INPUT connector and the low im- pedance side to the OHMS GUARD terminal. Unlock the ZERO CHECK button. Read the resistance. The low terminal of the INPUT connector is now a driven guard. It may be used to minimize the effects of capacity be- tween high and low and errors due to leakage resistance be- tween high and low. The Model 6011 Input Cable, supplied with the Model 602, provides a convenient means of making guarded resistance measurements. Connect the shorting link between the CASE GROUND and OHMS GUARD terminals on the rear panel. This allows the CASE GROUND or green test lead terminal to be connected to the low impedance side of the unknown resistance. The inner shield or the black test clip is the OHMS GUARD terminal. 2.9.3 Voltmeter-Ammeter Method ITo 10%) Turn the ZERO CHECK switch to LOCK. Connect sample between high terminal of the INPUT connector and power supply (See Figure 2-6). Put a switch in the high voltage line to connect the low impedance end of sample to input low when it is disconnected from the potential. If the power supply must be floating, remove the link be- tween the CASE GROUND and LO terminals and connect the CASE GROUND terminal to an earth ground. Set the FEEDBACK switch to NORMAL. Usually this method is best, since instabilities can arise for resistance samples less than 0.1 the value of
