KEI28039I(Model616) 电路图.pdf

INSTRUCTION MANUAL Digital Electrometer Model 616 COPYRIGHT 1975 KEITHLEY INSTRUMENTS, INC. NINTH PRINTING, FEBRUARY, 1980, CLEVELAND, OHIO, U. S. A. DOCUMENT NO. 28039 RadioFans.CN 收音机爱 好者资料库 COWENTS CONTENTS Section Page SpECIFIC*TIONS - i” 1. GENW*tci seetinp Accuracy 103 to lob fuli range in a decade ranges. 100% overranging to 1999 on all ranges. ACCURACY (20C to 3OC): (5% of reading +O.l% of range) 0 a11 ranges. 1 AS A CONSTANT CURRENT SOURCE RANGE: 8 CurrentS in decade seeps from 10-5 fo lo-12 ampere using OHMS ranges. Hi eermina1 is positive. COmJLIANCE: up to 200 volts. ACCURACY (ZOC eo 3OC): 20.5% from 10-5 eo lo-7 ampere. *2% at 10-a ampere. ?5% from 10-9 to 10-12 ampere. LOAD REGULATION: 1011 ohms. Better than 0.1% for loads up to GENERAL DISPLAY: 3 digits plus 1 overrange digit; decimal position, polarity, and overload indicaeio; 5 readings per second. Depending on sensitiviey setting, 3 least-siificant digits blink or blaok he overload condition exists. POLARITY SELECTION: Automatic SENSITIVITY SELECTION: Automatic: Voltage sensi- tivity selection is fully sutomstic. sensieiviey selection is aWma?Lc hlo decades above and be- low range switch setting for resistance, charge, and most current measurements. Manual: Front panel switch. Remote: Progrsnmsble with the Model 6162 Output/Control (optional). ISOLATION: Circuit Lo to chassis ground; greater than LO9 ohms shunted by 500 picofarads (decreas- ing to lOa ohms at 3OC and 70% relative humidity). Circuit Lo ma be floated UD to tlOO0 voles with respect eo chassis ground. ANALOG OUTPUTS: Unity Gain: For dc inputs, oueput is equal to input within 20 ppm far oueput cur;ers Of 1mA or less. In Jhe fasf mode output polarity is opposite input polarity. 1 vo1c: ?l volt at up fo 1mA with respect to circuit Lo for full range inwt: 100% oelxs!Le caoaLli1iev. I tile normal mode rhe outpue pol binding poses. BCD Output: 1neerna1 coeceors for interfacing ?he Node1 6162 Isolated OutpuflConCrol. DIMENSIONS; WEIGHT: Style M 3-l/2 in. half-rack, OVer811 bench size 4 in. high x a-314 in. wide x 15-314 in. deep (100 x 220 x 400 mm); et weighC, 11 pounds (4,a kg). POWER: Line Operario: go-125 0r 180-250 volts (switch selected), 50-60 Hz, 9 watts. ACCESSORIES SUPPLIED: Model 6011 Input Cable: 3 ft. (lm) rriaxial cable with triaxial coector and 3 auigaeor clips. iv 0374 SECTION 1. GENERAL INFORMATION l-l. INTRODUCTION. The Model 616 Digital Electro- meter is an automatic ranging, multipurpose electro- meter featuring sensitivity to 10 microvolts per digit. Its 3-l/2 digit LED display provides 0.2% voltage accuracy for a wide range of measuremente. The Model 616 is essentially a digital multimeter optimized for measurements from high source impe- dance. The 616 provides wide range capability when measuring current, resistance, and charge in addition to voltage. 1-2. WARRANTY INFORMATION. The warranty is stated an the inside front cover of the manual. l-3. CHANGE NOTICE. Improvements or changes to the instrument not incoqmrated into the manual will be explained on a Change Notice Sheet attached to the inside back cover. 0773 1 GENERAL INFORMATION MODEL 616 TABLE 1-l. Front Panel Controls Control Power ON SENSITIITY ZERO RANGE FAST/NOW ZERO CHECK INPUT Functional Description Controls line power. Sets voltage sensitivity and decimal paint. Adjusts zero affset. Sem range on a chosen function. Sets instrument for either Feedback or Shunt Mode. Places instrument in ZERO CHECK mode. Triaxial input receptacle. Paragraph - 3-4a 3-4a 3-3 3-7b 3-6 3-2a FAST/NORMAL s103 ZERO CHECK I POWEk ON SENSIiIVITY RANGE n rhe inner shield is the law inout: and the outer shield ie case ground. The m connector is a Keirhley part 0. CS-141 triaxia1 plug. b. Model 6011 Input Cable. This cable is a 30 inch long triaxial cable terminated with 3 color- coded alligator clips. The input high is identified by the heavy wire with red insulator. The input low is identified by the thin wire with black in- sulator. The case ground is identified by the thin wire with green insulator. C. Rear Panel Terminals. The rear panel has six binding posts which are used for making special connections to the Model 616. 1. Xl Terminal (White). This terminal provides an analo,q signal at unity gain. CAUTION Up to 200 volts my be present at this terminal. 2. 1 Terminal (Red). This terminal provides an analog signal wivh a scale factor of 1 volt far full range input. 3. Lo Terminals (Black). These terminals provide a connection to input low. Either terminal may be used for system connections. 4. GUARD Terminal (Blue). This terminal pro- vides a connection to the amplifier feedback when in the FAST made. 5. GROUND Terminal (Green). This terminal pro- vides a connection to chassis ground. A shorting link is provided for easy connections between lo and chassis. For floating applications, the link must be removed. GROUND 3-3. HOW TO SELECT FUNCTION. The Model 616 provides a sinele front-anel rotarv switch for selection of function and range. The RANGE Switch (5101) permits manual selection of any of four functions, namely, VOLT, OHMS, COULOMB, and AMPERE. 3-4. HOW TO SE THE, VOLT FUNCTION. The Model 616 provides five decades of voltage sensitivity from .OlOOO volts to 100 volts full range. The VOLT func- tion is selected by setting the RANGE switch to VOLT. a. Manual Sensifivity Setfins. The front panel SENSITIVITY switch has six positions. ks the switch is rotated counter clockwise, the sensitivity is increased. These positions correspond to full range sensitivities of lOO.OV, lO.OOV, l.OOOV, .lOOOV, and .OlOOOV as in Table 3-1. Position six is the AUTO sensitiviry mode which enables either *to- matic sensitivitv or remotely selected sensitivitv (when used with the Model 6162). See paragraph 3-4 for a complete explanation of AUTO mode. TABLE 3-1. Voltage Sensitivity Settings Senslriviey Full Range Maximum Setting Display Display I 10 nlv .01000 v f .01999 v 100 nlv .lOOO v f .1999 v I 10 1v v 1.000 10.00 v V v f i f 1.999 19.99 v v 100 100.0 199.9 v* *The display indicates OOO.OV at 200.0 volra input. The three least significant digits will flash on and off (blinking action) to indicate an over- voltage condition. The display will continue to read up to f201.7 volts with blinking action. Be- yond f201.7 olts the display will indicate 001.7 volts with blinking action. Valtaae inputs ,q.reater than f200 volts are not r;comm 8 ranges on OHMS, 4 ranges n COULOMB, and 11 ranges on AMPERE. Since the SENSITIVITY switch is used in conjunction with the RANGE Switch, the actual number of usesble spans is 12 decades on OHMS, 8 decades an COULOMB, and 11 on AMPERE. NOTE (ON AMPERE FUNCTIONl On the 10qlA t 104A ranges, the voltage be- veloped must not exceed 2 volts, otherwise, overheating of s range resistor could result. As s result, the 10 Volt and 100 volt sensi- tivity settings ate not recommended for lo-l1 to 1O-4A ranges. TO interpret a reading an OHMS, COULOMB, or AMPERE ranges both the digital display (with decimal location) snd the RANGE settig(powers of ten)shauld be cansi- dered. For example, given a digital reading of 17.32 and a RANGE setting of 1O-7 AMPERE, the actual meas- ured value would be interpreted ss 17.32 x lO-7 ampere. Since the decimal point is moveable, it is important to notice the position of the demimal point to deter- mine the full range of the instrument. See Table 3-3 for typical range settings in the AMPERE function. TABLE 3-3. Typical Current Range Settings* Input Range SeSitiity Digital current setting setting Display *The current reading is interpreted by multiplying the display reading times the range setting. Other cuc- rents not show can be measured by selecting the spprpriste RANGE switch setting in decade steps from lo-1A to lo-lA. 3-6. HOW TO MEASURE VOLTAGE. The Model 616 can be used to measure voltages from ilO microvolts to i200 volts. Although the Model 616 is useable as a gener- al purpose digital voltmeter, it has certain charac- teristics which enable reliable measrement from very-high source resistsnces. When used in the VOLT mods, the M el 616 has B input resistance greater than 2 x 10%. As a result, the loading of the source circuitry is relatively insignificant when compared to typical digital voltme-cers having LOS ohms input resistance. The Model 616 has 20 pico- farads of shunt capacitance (not including the input cable capacitance), since a large *ot Of capaci- tance causes a slowing of response, the input capaci- ty ,shauld be kept 8s small as possible. a. Measurements From Very High Source Resistance. TO se the Model 616 as a voltmeter, set the front pane1 controls as follows: RANGE - VOLT SENSITIVITY - AUTO FAST/NORMAL - NOW Connect a Model 6011 Triax Cable (or other shielded triaxial cable) to the INPUT receptacle. Keep cable length as short as possible to reduce the slowing effects of cable capacitance. The ser control may need occasional adjustment to reduce any voltage offset which msy occur due to temperature variations. To resero the Model 616, set the ZERO CHECK switch to CHECK position and adjust the front panel ZERO control for a O-O-O-O display. The Model 616 pra- vides a direct reading voltage display with automatic decimal point position and polarity. 6 0476 OPERATING INSTRUCTIONS I i I -_ - SOURCE ERROR DUE TO CIRCUIT LOADING ELECTI(OMETER % ERROR = 100 R R + RIN b. Measurements From Low source Resist.a”ce. TO se the Model 616 for voltage measurements from low ource resistances, set the RANGE switch to the lo-l1 AMPERE position. In this mode, the Model 616 input resistance is reduced to 1011 ohms; as a result the electrometer will be lees sensitive to electrical noise pickup and input cable vibration. Voltage measurements can be made by following the same procedure given in paragraph 3-6a. The Model 616 can be used with the RANGE eet et any position be- tween 10-11 AMPERE to 10-l AMPERE. The Model 616 input resisLence can be determined by taking the reciprocal of the AMPERE setting. Significant load- ing error may result if the input reeisrsnce 18 reduced to less than 100 x the source resistance. C. Measuremenrs Above 200 Volts. The Model 616 can be used with accessory divider probes to measure voltages up to 30 kilovolts. Range muse be set to VOLT. 1. Model 6102A Divider Probe (1O:l). This accessory extends the voltage mesauring capability of the Model 616 to 1000 volts. The inpa resis- tance is lOlo ohms. The divider accuracy is +4% to 1000 volts. (To use the Model 6102A en acceee- ory Model 6012 Adapter is needed LO mete the triax- ial input with the UHF connector a the probe.) 2. Model 6601A Divider (1OO:l). This accessory extends the voltage measuring capability of the Model 616 to 5000 volts. The input resistance is lo7 ohms. The divider accuracy ia +0.01X. 3. Model 6103A Divider Probe (1OOO:l). This accessory extends the voltage measuring capability of the Model 616 to 30 kilovolts. The input re- sistance is 10 ohma. The divider accuracy is f5% to 30 kilovolta. (To uee the Model 6103A an accessory Model 6012 Adapter ie needed to mate the triaxial input with the HP connector on the probe.) 1175 The Model 616 may exhibit a large amount of zero offset or drift immediately after an overload or e long period of storage. I addition, the offset current may exceed the specification for a short time until the Model 616 ia sufficiently stabilized. Although the offset current of the Model 616 is well below offset found in conventional voltmeters, the effects of the offset current charging the input capscitance may be ociced when the input is open. se the ZERO CHECK switch to discharge the offset charge. The Model 616 should ot be operated with cir- cuit low fleeting by greater than 1000 volta with respect to chassis ground. If the Model 616 is to be used with circuit low floating make certain that no connection is made be- tween the LOW and GROUND terminals o the rear panel. Do not connect a grounded re- corder or other instrument to the Xl or 1V outpute when the Model 616 is floated. d. Voltage Measurements in FAST Mode. when the FAST/NORMAL Switch is eet to FAST, the Model 616 is connected in a FEEDBACK amplifier configuration. In this configuration, the Model 616 requires special connectians. To measure voltage, coect the eource between input HI and GUARD. A easy way to accom- plish this connection ie Lo connect the link (on the rear panel) between GUARD (blue terminal) and GROUND (green terminal). Then uee the rriaxial cable far input connectione with the input voltage applied between the red clip lead and the green clip lead. NOTE In this special voltage connection, the LO input (black clip lead) is of used since the voltage amplifier Configuration has bee changed. 7 OPERATING INSTRUCTIONS MODEL 616 c-c- c-c- -F- -F- l l R R I I l l I I II-, II-, I I ; ; MEASURING MXASURING i i - - I I POINTS POINTS T T I I : : I I L L -WC- -WC- _I _I L1-_-! L1-_-! SOURCE SOURCE ELECTROMETER ELECTROMETER ” = I x Rm ” = I x Rm P1GP.E 7. PICURE 7. operation As A hater in NORMAL Mode. operation As A hater in NORMAL Mode. 3-7. HOW To MEASURE CURRENT. The Model 616 can be wed to measure currents from *lo-15 ampere to 200 mill*peres. Although the Model 616 is useable a8 a general purpose picoammerer, it has certain charac- teristics which enable reliable measurements of very small current8 with fast response. a. Normal Mode Current Measurements. (Use FAST mode for current below lo-5A.) I this mode, the Model 616 measures current ver a wide range. When the FAST/NORMAL switch is set to NORMAL, the Model 616 operates as a shunt-type picaammeter in which a resistor is connected directly across the input ter- minals. The Model 616 measures the voltage drop acro.m the shunt resistors where VIN - IIN x RS. This method of measurement is typical of mast multi- meter current measuring techniques. To use the Model 616 as a shunt-type pidoammeter, eat the front panel controls *s fallows: RANGE - 10-5 AMPERE (or appropriate range) SENSITIVITY - AUTO PAST/NORMAL - NORMAL NOTE - Full range is determined by the sensitivity setting and the AMPERE range setting. Connect a Model 6011 Triax Cable (or other shielded eriaxial cable) to the INPUT receptacle. Keep cable length as short as possible to reduce the slowing effects of cable capacitance. The zero control may need occasional adjustment to reduce any voltage offset which may occur due to temperature variations. To rezer the Model 616, set the ZERO CHECK switch to CHECK position and adjust the front panel Zero control for a O-O-O-O display. The Model 616 may exhibit a large emut of zero offset or drift immediately after a overload or a long period of storage. I additio