2182A

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LOW LEVEL MEASURE & SOURCE A Greater Measure of Confidence www.keithley.com 1.888.KEITHLEY (U.S. only) Low noise measurements for research, metrology, and other low voltage testing applications The two-channel Model 2182A Nanovoltmeter is optimized for making stable, low noise voltage measurements and for characterizing low resistance materials and devices reliably and repeatably It provides higher measurement speed and significantly better noise performance than alternative low voltage measurement solutions T he Model 2182A represents the next step forward in Keithley nanovoltmeter technology, replacing the original Model 2182 and offering enhanced capabilities including pulse capability, lower measurement noise, faster current rever- sals, and a simplified delta mode for making resistance measurements in combination with a reversing current source, such as the Model 6220 or 6221

• M ake low noise measurements at high speeds, typically just 15nV p-p noise at 1s response time, 40–50nV p-p noise at 60ms D elta mode coordinates measurements with a reversing current source at up to 24Hz with 30nV p-p noise (typical) for one reading. av erages multiple readings for greater noise reduction sy nchronization to line provides 110db NMr r and minimizes the effect of aC c ommon-mode currents
• D ual channels support measuring voltage, temperature, or the ratio of an unknown resistance to a reference resistor bu ilt-in thermocouple linearization and cold junction compensation fi gure 1. Compare the Model 2182 a’ s DC noise performance with a nanovolt/micro-ohm - meter’s. al l the data shown was taken at 10 readings per second with a low thermal short applied to the input. -100 -50 100 150 Keithley 2182A nV/µΩ Meter 0 100Number of Readings nV fl exible, Effective sp eed/Noise Trade-offs The Model 2182A makes it easy to choose the best speed/filter combination for a particular applica - tion’s response time and noise level requirements . The ability to select from a wide range of response times allows optimizing speed/noise trade-offs . Low noise levels are assured over a wide range of useful response times, e .g ., 1 5nV p-p noise at 1s and 40-50nV p-p noise at 60ms are typical . Figure 1 illustrates the Model 2182A’s noise performance . 2182a Nanovoltmeter

LOW LEVEL MEASURE & SOURCE www.keithley.com 1.888.KEITHLEY (U.S. only) A Greater Measure of Confidence Low noise measurements for research, metrology, and other low voltage testing applications Reliable Results Power line noise can compromise measurement accuracy significantly at the nanovolt level. The Model 2182A reduces this interference by synchronizing its measurement cycle to line, which minimizes variations due to readings that begin at different phases of the line cycle. The result is exceptionally high immunity to line interference with little or no shielding and filtering required. Optimized for Use with Model 6220/6221 Current Sources Device test and characterization for today’s very small and power-efficient electronics requires sourc - ing low current levels, which demands the use of a precision, low current source. Lower stimulus currents produce lower—and harder to measure—voltages across the devices. Linking the Model 2182A Nanovoltmeter with a Model 6220 or 6221 Current Source makes it possible to address both of these challenges in one easy-to-use configuration. When connected, the Model 2182A and Model 6220 or 6221 can be operated like a single instrument. Their simple connections eliminate the isolation and noise current problems that plague other solu - tions. The Model 2182A/622X combination allows making delta mode and differential conductance measurements faster and with less noise than the original Model 2182 design allowed. The Model 2182A will also work together with the Model 6221 to make pulse-mode measurements. The 2182A/622X combination is ideal for a variety of applications, including resistance measure- ments, pulsed I-V measurements, and differential conductance measurements, providing significant advantages over earlier solutions like lock-in amplifiers or AC resistance bridges. The 2182A/622X combination is also well suited for many nanotechnology applications because it can measure resistance without dissipating much power into the device under test (DUT), which would otherwise invalidate results or even destroy the DUT. An Easy-to-Use Delta Mode Keithley originally created the delta mode method for measuring voltage and resistance for the Model 2182 and a triggerable external current source, such as the Model 2400 SourceMeter ® SMU instrument. Basically, the delta mode automatically triggers the current source to alternate the signal polarity, and then triggers a nanovoltmeter reading at each polarity. This current reversal technique

Ordering Information

2107-4 Low Thermal Input Cable with spade lugs, 1.2m (4 ft). User manual, service manual, contact cleaner, line cord, al ligator clips. DC Measurement Delta Mode Measurement 4µV 5nV

AppLICATIONS

• De termining the transition temperature of superconductive materials
• I- V characterization of a material at a specific temperature
• Cal orimetry
• Di fferential thermometry
• Sup erconductivity
• Nan omaterials Metrology
• In tercomparisons of standard cells
• Nu ll meter for resistance bridge measurements ACCESSORIES AVA ILAbLE 2107-30 Lo w Thermal Input Cable with spade lugs, 9.1m (30 ft) 2182-KIT Lo w Thermal Connector with strain relief 2187-4 Lo w Thermal Test Lead Kit 2188 Lo w Thermal Calibration Shorting Plug 4288-1 Si ngle Fixed Rack Mount Kit 4288-2 Du al Fixed Rack Mount Kit 7007-1 Sh ielded GPIB Cable, 1m (3.2 ft) 7007-2 Sh ielded GPIB Cable, 2m (6.5 ft) 7009-5 Sh ielded RS-232 Cable, 1.5m (5 ft) 8501-1 Tr igger Link Cable, 1m (3.2 ft) 8501-2 Tr igger Link Cable, 2m (6.5 ft) 8503 Tr igger Link Cable to 2 male BNC connectors KPCI-488LPA IE EE-488 Interface/Controller for the PCI Bus KUSB-488B IE EE-488 USB-to-GPIB Interface Adapter SERVICES AVA ILAbLE 2182A-3Y-EW 1- year factory warranty extended to 3 years from date of shipment C/2182A-3Y-ISO 3 (I SO-17025 accredited) calibrations within 3 years of purchase* * Not available in all countries

Figure 2. Results from a Model 2182A/6220 using the delta mode to measure a 10m W resistor software used here can be downloaded from www.keithley.com.

LOW LEVEL MEASURE & SOURCE A Greater Measure of Confidence www.keithley.com 1.888.KEITHLEY (U.S. only) Low noise measurements for research, metrology, and other low voltage testing applications 2182a Nanovoltmeter cancels out any constant thermoelectric offsets, so the results reflect the true value of the voltage being measured The improved delta mode for the Model 2182A and the Model 622X current sources uses the same basic technique, but the way in which it’s implemented has been simplified dra- matically The new technique can cancel thermoelectric offsets that drift over time (not just static offsets), produces results in half the time of the original technique, and allows the current source to control and configure the Model 2182A Two key presses are all that’s required to set up the measurement The improved cancellation and higher reading rates reduce measurement noise to as little as 1nV . D ifferential Conductance Measurements Characterizing non-linear tunneling devices and low temperature devices often requires measuring differential conductance (the derivative of a device’s I-V curve) When used with a Model 622X current source, the Model 2182A is the industry’s fastest, most complete solution for differen- tial conductance measurements, providing 10X the speed and significantly lower noise than other instrumentation options There’s no need to average the results of multiple sweeps, because data can be obtained in a single measurement pass, reducing test time and minimizing the potential for measurement error P ulsed Testing with the Model 6221 When measuring small devices, introducing even tiny amounts of heat to the DUT can raise its temperature, skewing test results or even destroying the device When used with the Model 2182A, the Model 6221’s pulse capability minimizes the amount of power dissipated into a DUT The Model 2182A/6221 combination synchronizes the pulse and measurement A measurement can begin as soon as 16µs after the Model 6221 applies the pulse The entire pulse, including a complete nanovolt measure- ment, can be as short as 50µs . I n the delta, differential conductance, and pulse modes, The Model 2182A produces virtually no transient currents, so it’s ideal for characterizing devices that can be easily disrupted by current spikes (see Figure 4) M etrology app lications The Model 2182A combines the accuracy of a digital multimeter with low noise at high speeds for high-precision metrology applications Its low noise, high signal observation time, fast measurement rates, and 2ppm accuracy provide the most cost-effective meter available today for applications such as intercomparison of voltage standards and direct measurements of resistance standards N anotechnology app lications The Model 2182A combined with the Model 622X current source or Series

2400 SourceMeter

® SMU instrument is a highly accurate and repeatable solution for measuring resistances on carbon nanotube based materials and silicon nanowires fi gure 3. It’s simple to connect the Model 2182 a to the Model 6220 or 6221 to make a variety of measurements. The instrument control example start-up software available for the Model 622X current sources includes a step-by-step guide to setting up the instrumentation and making proper connections. GPIB or Ethernet RS-232 Trigger Link DUT 2182A NANOVOLTMETER 6220 DC AND AC CURRENT SOURCE Model 2182A Model 622X 0.5µA100µs fi gure 4. The Model 2182 a produces the lowest transient currents of any nanovoltmeter available. Competition 2182a 2 182a i n delta mode research ap plications The Model 2182A’s 1nV sensitivity, thermoelectric EMF cancellation, direct display of “true” voltage, ability to perform calculations, and high measure - ment speed makes it ideal for determining the characteristics of materials such as metals, low resistance filled plastics, and high and low temperature superconductors

LOW LEVEL MEASURE & SOURCE www.keithley.com 1.888.KEITHLEY (U.S. only) A Greater Measure of Confidence Low noise measurements for research, metrology, and other low voltage testing applications op tional ac cessory: Model 2187-4 low Thermal Test le ad Kit The standard cabling provided with the Model 2182A Nano v olt me ter and Model 622X Current Sources provides everything normally needed to connect the instruments to each other and to the DUT The Model 2187-4 Low Thermal Test Lead Kit is required when the cabling provided may not be sufficient for specific applications, such as when the DUT has special connection requirements The kit includes an input cable with banana terminations, banana extensions, sprung-hook clips, alligator clips, needle probes, and spade lugs to accommodate virtually any DUT The Model 2187-4 is also helpful when the DUT has roughly 1GW impedance or higher . I n this case, measuring with the Model 2182A directly across the DUT will lead to loading errors The Model 2187-4 Low Thermal Test Lead Kit provides a banana cable and banana jack extender to allow the Model 2182A to connect easily to the Model 622X’s low impedance guard output, so the Model 2182A can measure the DUT voltage indirectly This same configuration also removes the Model 2182A’s input capacitance from the DUT, so it improves device response time, which may be critical for pulsed measurements Three Ways to Measure Nanovolts DC nanovoltmeters. DC nanovoltmeters and sensitive DMMs both provide low noise DC voltage measurements by using long integration times and highly filtered readings to minimize the bandwidth near DC U nfortunately, this approach has limitations, particularly the fact that thermal voltages develop in the sample and connections vary, so long integration times don’t improve measurement precision With a noise specification of just 6nV p-p, the Model 2182A is the lowest noise digital nanovolt me ter available . A C technique. The limitations of the long integration and filtered readings technique have led many people to use an AC technique for measuring low resistances and voltages I n this method, an AC excitation is applied to the sample and the voltage is detected syn c hronously at the same frequency and an optimum phase . While this technique removes the varying DC component, in many experiments at high frequencies, users can experience problems related to phase shifts caused by spurious capacitance or the L/R time constant At low frequencies, as the AC frequency is reduced to minimize phase shifts, amplifier noise increases T he current reversal method. The Model 2182A is optimized for the current reversal method, which combines the advantages of both earlier approaches In this technique, the DC test current is reversed, then the difference in voltage due to the difference in current is determined Typically, this measure men t is performed at a few hertz (a frequency just high enough for the current to be reversed before the thermal voltages can change) The Model 2182A’s low noise performance at measurement times of a few hundred milliseconds to a few seconds means that the reversal period can be set quite small in comparison with the thermal time constant of the sample and the con n ections, effectively reducing the impact of thermal voltages 180 185 190 195 200 205 210 215 220 08 17 25 33 42 50 58 67 75 83 92 1001 08 117 125 Voltage (nV) Temperature (°C) Minutes –10 fi gure 5. The Model 2182 a’ s delta mode provides extremely stable results, even in the pres - ence of large ambient temperature changes. In this challenging example, the 200nV signal results from a 20µa current sourced by a Model 6221 through a 10m W test resistor. 2182a Nanovoltmeter fi gure 7. Model 2182 a rear panel fi gure 6. Model 2187-4 Test le ad Kit

LOW LEVEL MEASURE & SOURCE A Greater Measure of Confidence www.keithley.com 1.888.KEITHLEY (U.S. only) Model 2182A specifications Volts sp ecifications (20% over range) CON DITIONS : 1PLC with 10 reading digital filter or 5PLC with 2 reading digital filter . ac curacy: ±(ppm of reading + ppm of range) ( ppm = parts per million) (e.g., 10ppm = 0.001%) Temperature Channel 1 I nput

4 Hour 1 9 0 Day 1 Y ear 2 Y ear C oefficient

r an ge re solution re sistance TCal ±1°C TCal ±5°C TCal ±5°C TCal ±5°C 0 °–18°C & 28°–50°C 1 0 .000000 mV 2, 3, 4 1 n V > 10 GW 2 0 + 4 4 0 + 4 5 0 + 4 6 0 + 4 ( 1 + 0 .5 )/°C 00 .0 0000 m V 0 nV GW 0 + 3 5 + 3 0 + 4 0 + 5 1 + 0 .2 )/°C 1 .0000000 V 1 00 nV > 10 GW 7 + 2 8 + 2 5 + 2 2 + 3 1 + 0 .1 )/°C 0 .0 00000 V 1 µ V GW 2 + 1 5 1 8 + 2 2 5 + 2 3 2 + 3 ( 1 + 0 .1 )/°C 00 .00000 V 4 1 0 µV 1 0 MW ±1% 1 0 + 3 2 5 + 3 3 5 + 4 5 2 + 5 ( 1 + 0 .5 )/°C Channel 2 6, 10 1 00 .0 0000 m V 1 0 nV > 10 GW 1 0 + 6 2 5 + 6 3 0 + 7 4 0 + 7 ( 1 + 1 ) /°C 1 .0000000 V 1 00 nV > GW 7 + 2 8 + 2 5 + 2 2 + 3 1 + 0 .5 )/°C 0 .0 00000 V 1 µ V GW 2 + 1 5 1 8 + 2 2 5 + 2 3 2 + 3 ( 1 + 0 .5 )/°C CHANNEL 1/CHANNEL 2 RATIO: For input signals ≥ 1% of the range, Ratio Accuracy = ±{[Channel 1 ppm of Reading + Channel 1 ppm of Range * (Channel 1 Range/Channel 1 Input)] + [Channel 2 ppm of Reading + Channel 2 ppm of Range * (Channel 2 Range/Channel 2 Input)]} . D ELTA (hardware-triggered coordination with Series 24XX, Series 26XXA, or Series 622X current sources for low noise R measurement): Accuracy = accuracy of selected Channel 1 range plus accuracy of I source range . D ELTA M EASUREMENT N OISE W ITH 6220 or 6221: Typical 3nVrms / Hz (10mV range)21 . 1Hz achieved with 1PLC, delay = 1ms, RPT filter = 23 (20 if 50Hz) . P ULSE-MODE ( W ITH 6221): Line synchronized voltage measurements within current pulses from 50µs to 12ms, pulse repetition rate up to 12Hz . PU LSE M EASUREMENT N OISE (typical rms noise, R DUT<10W): ±(0 .0 09ppm of range*) / meas_time / pulse_avg_count + 3nV** / (2 · meas_time · pulse_avg_count) for 10mV range . * 0 .0 028ppm for the 100mV range, 0 .0 016ppm for ranges 1V and above . 8nV/ Hz for ranges above 10mV . meas_time (seconds) = pulsewidth – pulse_meas_delay in 33µs incr . DC Noise Performance 7 (DC noise expressed in volts peak-to-peak) Response time = time required for reading to be settled within noise levels from a stepped input, 60Hz operation . Channel 1 re sponse ran ge T ime N PlC , fi lter 1 0 mV 1 00 mV 1 V 1 0 V 1 00 V N Mr r 8 CMrr 9 2 5 .0 s 5 , 75 6 n V 2 0 nV 7 5 nV 7 50 nV 7 5 µV 1 10 dB 1 40 dB 4 .0 s , 10 5 nV 0 nV 50 nV 1 .5 µ V 5 µV 00 dB 40 dB 1 .0 s , 18 5 nV 75 nV 00 nV 2 .5 µ V 00 µV 5 dB 40 dB m s , 10 or 5, 2 5 nV 50 nV 50 nV 3 .3 µ V 50 µV 0 dB 40 dB m s , Off 0 nV 00 nV 00 nV 6 .6 µ V 00 µV 0 dB 40 dB Channel 2 6, 10 2 5 .0 s 5 , 75 — 1 50 nV 2 00 nV 7 50 nV — 1 10 dB 1 40 dB 4 .0 s , 10 50 nV 00 nV 1 .5 µ V 00 dB 40 dB 1 .0 s , 10 or 5, 2 75 nV 00 nV 2 .5 µ V 0 dB 40 dB m s , Off 25 nV 1 µ V 9 .5 µ V 0 dB 40 dB VolTaG E NoIsE Vs . so urC E rE s Is TaN CE 11 (DC noise expressed in volts peak-to-peak) s o urce an alog D igital r e sistance N oise fi lter fi lter

0 W 6 n V O ff 1 00

V O ff kW 5 nV O ff kW 5 nV O ff kW 00 nV O n MW 50 nV O n TE MPE r a TurE (T hermocouples) 12 aCCu ra CY Displayed in °C, ° f, o r K. ac curacy based on

0 Day/1 Year

0, exclusive of thermocouple errors.) 2 3° ±5°C re lative to si mulated TY PE r aN GE rE s oluT IoN re ference Junction J – 200 to + 760°C 0 .0 01 °C ± 0 .2 ° C K 200 to 1372°C 0 .0 01 °C 0 .2 ° C N 200 to 1300°C 0 .0 01 °C 0 .2 ° C T 200 to 400°C 0 .0 01 °C 0 .2 ° C E 200 to 1000°C 0 .0 01 °C 0 .2 ° C R 0 t o 1768°C 0 .1 ° C 0 .2 ° C S 0 t o 1768°C 0 .1 ° C 0 .2 ° C B 350 to 1820°C 0 .1 ° C 0 .2 ° C 2182a Nanovoltmeter oper ating Characteristics 13, 14 60Hz (50Hz) op eration f u nction D igits r e adings/s PlC s D CV Channel 1, 7 .5 3 (2) 5 C hannel 2, .5 17, 19 6 (4) 5 T hermocouple 6 .5 18, 19 1 8 (15) 1 6 .5 18, 19, 20 4 5 (36) 1 5 .5 17, 19 8 0 (72) 0 .1 4 .5 16, 17, 19 1 15 (105) 0 .0 1 C hannel 1/Channel 2 (Ratio), 7 .5 1 .5 (1 .3 D elta with 24XX, Scan .5 17, 19 2 . 3 (2 .1 ) 5 6 .5 18 8 .5 (7 .5 ) 1 6 .5 18, 20 2 0 ( 16) 1 5 .5 17 3 0 ( 29) 0 .1 4 .5 17 4 1 (40) 0 .0 1 D elta with 622X 6 .5 (40 .0 ) 22 1 system sp eeds 13, 15 RA NGE CH ANGE TI ME: 14 < 40 ms ( <50 ms) . FU NCTION CH ANGE TI ME: 14 < 45 ms ( <55 ms) . AU TORANGE TI ME: 14 < 60 ms ( <70 ms) . A SCII RE ADING T O RS-232 (19.2K Baud): 40/s ( 40/s) . MA IN TERNAL TR IGGER RA MA EX TERNAL TR IGGER RA

LOW LEVEL MEASURE & SOURCE www.keithley.com 1.888.KEITHLEY (U.S. only) A Greater Measure of Confidence Model 2182A specifications Measurement Characteristics A/D L INEARIT y : ±(0 .8 ppm of reading + 0 .5 ppm of range) . FR ONT AU TO zE RO OF F ER ROR mV–10V: A dd ±(8ppm of range + 500µV) for <10 minutes and ±1°C . NOTE: O ffset voltage error does not apply for Delta Mode . AU TO zE RO OF F ER ROR 0mV: A dd ±(8ppm of range + 100nV) for <10 minutes and ±1°C . 100mV–100V: A dd ±(8ppm of range + 10µV) for <10 minutes and ±1°C . NOTE: O ffset voltage error does not apply for Delta Mode . INP UT IM PEDANCE mV–10V: >10GW, in parallel with <1 .5 nF (Front Filter ON) . 10mV–10V: >10GW, in parallel with <0 .5 nF (Front Filter OFF) . 100V: 10MW ±1% . D C IN PUT BI AS CU RRENT: <60pA DC at 23°C, –10V to 5V . <120pA @ 2 3°C, 5V to 10V . C OMMON MO DE CU RRENT: < 50nA p-p at 50Hz or 60Hz . INP UT PR OTECTION: 1 50V peak to any terminal . 70V peak Channel 1 LO to Channel 2 LO . CH ANNEL IS OLATION: > 10GW . EA RTH IS OLATION: 3 50V peak, >10GW and <150pF any terminal to earth . Add 35pF/ft with Model 2107 Low Thermal Input Cable . ana log ou tput MA XIMUM O UTPUT: ±1 .2 V . A CCURAC y : ±(0 .1 % of output + 1mV) . O UTPUT RE SISTANCE: 1kW ±5% . GA IN : Adjustable from 10 –9 to 106 . With gain set to 1, a full range input will produce a 1V output . O UTPUT REL: Selects the value of input that represents 0V at output . The reference value can be either programmed value or the value of the previous input . Triggering and Memory WI NDOW FI LTER SE NSITIVIT y : 0 .0 1%, 0 .1 %, 1%, 10%, or full scale of range (none) . RE ADING HO LD SE NSITIVIT y : 0 .0 1%, 0 .1 %, 1%, or 10% of reading . TR IGGER DE LAy: 0 t o 99 hours (1ms step size) . EX TERNAL TR IGGER DEL Ay : 2ms + <1ms jitter with auto zero off, trigger delay = 0 . ME MORy SIzE: 1 024 readings . Math fu nctions Rel, Min/Max/Average/Std Dev/Peak-to-Peak (of stored reading), Limit Test, %, and mX+b with user- defined units displayed . re mote Interface Keithley 182 emulation . G PIB (IEEE-488 .2 ) and RS-232C . S CPI (Standard Commands for Programmable Instruments) . GENEral PO WER S U PPL y : 100V/120V/220V/240V . LI NE FR EQUENCy : 50Hz, 60Hz, and 400Hz, automatically sensed at power-up . PO WER CO NSUMPTION : 22VA . MA GNETIC FI ELD DE NSITy : 10mV range 4 .0 s response noise tested to 500 gauss . OP ERATING EN VIRONMENT : S pecified for 0° to 50°C . Specified to 80% RH at 35°C . STO RAGE EN VIRONMENT : – 40° to 70°C . E MC: Complies with European Union Directive 89/336/EEC (CE marking requirement), FCC part 15 class B, CISPR 11, IEC 801-2, IEC-801-3, IEC 801-4 . SA FETy: Complies with European Union Directive 73/23/EEC (low voltage directive); meets EN61010-1 safety standard . Installation category I . VI BRATION: MIL-T-28800E Type III, Class 5 . WA RM -UP: 2 .5 h ours to rated accuracy . DI MENSIONS: Rack Mounting: 89mm high × 213mm wide × 370mm deep (3 .5 i n × 8 .37 in × 14 .5 63 in) . Bench Configuration (with handles and feet): 104mm high × 238mm wide × 370mm deep (4 .1 25 in × 9 .3 75 in ×14 .5 63 in) . SH IPPING WE IGHT: 5 kg (11 lbs) . 2182a Nanovoltmeter NoT E s 1 . R elative to calibration accuracy . 2 . W ith Analog Filter on, add 20ppm of reading to listed specification . 3 . W hen properly zeroed using REL function . If REL is not used, add 100nV to the range accuracy . 4 . S pecifications include the use of ACAL function . If ACAL is not used, add 9ppm of reading/°C from TCAL to the listed specification . TCAL is the internal temperature stored during ACAL . 5 . F or 5PLC with 2-reading Digital Filter . Use ±(4ppm of reading + 2ppm of range) for 1PLC with 10-reading Digital Filter . 6 . C hannel 2 must be referenced to Channel 1 . Channel 2 HI must not exceed 125% (referenced to Channel 1 LO) of Channel 2 range selected . 7 . N oise behavior using 2188 Low Thermal Short after 2 .5 h our warm-up . ±1°C . Analog Filter off . Observation time = 10 × response time or 2 minutes, whichever is less . 8 . F or LSYNC On, line frequency ±0 .1 % . If LSYNC Off, use 60dB . 9 . F or 1kW unbalance in LO lead . AC CMRR is 70dB . 0 . F or Low Q mode On, add the following to DC noise and range accuracy at stated response time: 200nV p-p @ 25s, 500nV p-p @ 4 .0 s, 1 .2 µV p-p @ 1s, and 5µV p-p @ 85ms . 1 . A fter 2 .5 h our warm-up, ±1°C, 5PLC, 2 minute observation time, Channel 1 10mV range only . 2 . F or Channel 1 or Channel 2, add 0 .3 °C for external reference junction . Add 2°C for internal reference junction . 3 . S peeds are for 60Hz (50Hz) operation using factory defaults operating conditions (*RST) . A utorange Off, Display Off, Trigger Delay = 0, Analog Output off . 4 . S peeds include measurements and binary data transfer out the GPIB . Analog Filter On, 4 readings/s max 5 . A uto Zero Off, NPLC = 0 .0 1 . 6 . 1 0mV range, 80 readings/s max . 7 . S ample count = 1024, Auto Zero Off . 8 . F or LSYNC On, reduce reading rate by 15% . 9 . F or Channel 2 Low Q mode Off, reduce reading rate by 30% . 0 . F ront Auto Zero off, Auto Zero off . 1 . A pplies to measurements of room temperature resistances <10 W, Isource range ≤ 20µA . 2 . D isplay off, delay 1ms .