Keysight 3458A Multimeter Calibration Manual
KEYSIGHT TECHNOLOGIES WARRANTY STATEMENT KEYSIGHT PRODUCT: 3458A Multimeter DURATION OF WARRANTY: 1 year 1.Keysight Technologies warrants Keysight hardware, accessories and supplies against defects in materials and workmanship for the period specified above. If Keysight receives notice of such defects during the warranty period, Keysight will, at its option, either repair or replace products which prove to be defective. Replacement products may be either new or like-new. 2.
Documentation History All Editions and Updates of this manual and their creation date are listed below. The first Edition of the manual is Edition 1. The Edition number increments by 1 whenever the manual is revised. Updates, which are issued between Editions, contain replacement pages to correct or add additional information to the current Edition of the manual. Whenever a new Edition is created, it will contain all of the Update information for the previous Edition.
DECLARATION OF CONFORMITY According to ISO/IEC Guide 22 and CEN/CENELEC EN 45014 Manufacturer’s Name: Manufacturer’s Address: Keysight Technologies, Incorporated 815 14th ST. S.W. Loveland, CO 80537 USA Declares, that the product Product Name: Model Number: Product Options: Multimeter 3458A This declaration covers all options of the above product(s).
Contents Chapter 1 3458A Calibration Introduction Introduction ............................................................. 7 Calibration Security ................................................. 7 Security Code ..................................................... 7 Changing the Security Code ............................... 8 Hardware Lock-Out of Calibration .................... 9 Number of Calibrations ...................................... 9 Monitoring For CAL Violations .......................
6 Contents
Chapter 1 3458A Calibration Introduction Introduction This manual provides operation verification procedures, adjustment procedures, and performance verification procedures for the 3458A Multimeter. WARNING The information contained in this manual is intended for the use of service-trained personnel who understand electronic circuitry and are aware of the hazards involved. Do not attempt to perform any of the procedures outlined in this section unless you are qualified to do so.
is shipped from the factory with its security code set to 3458. Specifying 0 for the new_code in the SECURE command disables the security feature making it no longer necessary to enter the security code to perform a calibration or autocal. Changing the Security Code The security code is changed with the SECURE command which has the following syntax: SECURE old_code, new_code [,acal_secure] The procedure for changing the security code is as follows: 1. Access the SECURE command.
display the SECURE command). f. Enter the number 0 followed by the delimiter (,) and the security code you want to use. g. Press the ENTER key. h. Turn the instrument off, disconnect power, and return jumper JM600 to the left position (front of instrument facing you). i. Replace the top cover and reconnect power. The instrument will now respond to the new security code you just entered. Note Hardware Lock-Out of Calibration When jumper JM600 is in the right position, the security feature is disabled (i.
CAL. (or ACAL if secured) is executed. If autocal is secured, the calibration number is also incremented by 1 whenever an autocal is performed; if unsecured, autocal does not affect the calibration number. Note The multimeter was adjusted before it left the factory. This has incremented the calibration number. When you receive the multimeter, read the calibration number to determine the initial value you start with. The procedure for reading the number of calibrations is presented after this note.
The remaining constants (such as internal reference and offset constants) are externally derived and not changed by an ACAL. Periodically you may want to monitor a particular constant and track its movement within the lower and upper limits (see CAL? command, cal_item parameter). This may give you an indication of the calibration cycle you want to establish for your 3458A.
12 Chapter 1 3458A Calibration Introduction
Chapter 2 Operational Verification Tests Introduction This section contains Operational Verification Tests which provide an abbreviated method of testing the operation and accuracy of the unit. The Operational Verification Tests are designed to provide a 90% confidence that the 3458A is operational and meets the specifications listed in Appendix A. Operational Verification Tests perform a three point verification.
→ scroll keys to view entire CAL? message. Record the temperatures on the Test Card. 7. If the instrument self test has not been run, make certain all inputs are disconnected and execute the TEST function. The display must read "SELF TEST PASSED". 8. Execute the ACAL OHMS function. This auto calibration will take approximately ten minutes to complete. 9. Configure the transfer standard DMM as follows: ----- OHM NDIG 8 NPLC 100 TRIG SGL 10.
9. 4-Wire Ohms Function Gain Test Remove the short from the rear input terminals. The following procedure verifies the gain of the ohms function. The 10 KΩ point is used for internal electronic calibration using ACAL. The procedure requires alternately connecting the transfer standard DMM and then the 3458A under test to the resistance verification standard as described in the Chapter 4 section titled "General Test Procedure". 1.
chapter 4, Performance Verification Tests. 1. Execute the ACAL DCV command using the front panel "Auto Cal" key and scroll keys. This auto calibration will take approximately two minutes to complete. 2. Configure the transfer standard DMM as follows: ----- 3. DCV NDIG 8 NPLC 100 Trig SGL Configure the DMM under test as follows: ----- DCV NDIG 8 NPLC 100 Trig SGL 4. Set the range of the transfer standard DMM to 10V (function = DCV). 5. Set the range of the 3458A under test to 10V (function = DCV).
Chapter 3 "Adjustment Procedures" to make adjustments. DC Voltage Function Offset Test Turnover Check This procedure tests the DCV offset voltage specification on the 10V range. This reading and the 10V and -10V readings from the previous DCV gain test are used to do a turnover check of the A-D converter and verify its linearity. 1. Connect a low thermal short across the front panel HI and LO input terminals of the DMM under test (see Figure 1 on page 23). 2.
18 Chapter 2 Operational Verification Tests
OPERATIONAL TEST CARD - 1 YEAR LIMITS Keysight Model 3458A Digital Multimeter Test Performed By Serial Number Date CAL? 60 TEMP? Difference - (must be less than 5 degrees C) Perform an ACAL OHMS Test # 3458A Input 3458A Range Transfer Standard Reading Unit Under Test Reading Difference Limit (Std) Limit (Opt 002) 2-Wire Ohms Function Offset Tests 1 Short 10 Ω N/A N/A 00.25007 00.25007 N/A N/A 00.25007 00.25007 00.000142 00.
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Chapter 3 Adjustment Procedures Introduction This section contains procedures for adjusting the 3458A Multimeter. The 3458A uses closed-box electronic adjustment. No potentiometers or other electro-mechanical adjustments are used and the complete adjustment is done without removing any of the multimeter's covers. Only a voltage standard. A resistance standard, a low-thermal short, and an AC signal source are needed to perform all of the adjustments.
The resultant accuracy of the multimeter depends on the accuracy of the equipment used, the thermal characteristics of the short. and the type of cabling used. We recommend high impedance, low dielectric absorption cables for all connections. Preliminary Adjustment Procedure Perform the following steps prior to adjusting the 3458A: 22 1. Select the adjustment area. You can adjust the 3458A on the bench or in a system cabinet. The temperature of the adjustment environment should be between 15°C and 30°C.
Figure 1. 4-Terminal Short Front Terminal Offset Adjustment This adjustment uses an external 4-terminal short. The multimeter makes offset measurements and stores constants for the DCV, DCI, OHM, and OHMF functions. These constants compensate for internal offset errors for front terminal measurements. Equipment required: A low-thermal short made of 12 or 14 gauge solid copper wire as shown in Figure 1 on page 23. 1.
Note Take precautions to prevent thermal changes near the 4-wire short. You should not touch the short after it is installed. If drafts exist, you should cover the input terminals/short to minimize the thermal changes. 4. Execute the CAL 0 command. The multimeter automatically performs the front terminal offset adjustment and the display shows each of the various steps being performed. This adjustment takes about 5 minutes.
standard). Note Voltage standards from 1V DC to 12V DC can be used for this procedure. However, using a voltage standard <10V DC will degrade the multimeter's accuracy specifications. 1. Select the DC Voltage function. 2. Set the front panel Terminals switch to Front. 3. Connect the voltage standard to the multimeter's front panel HI and LO Input terminals as shown in Figure 2. If using a Guard wire (as shown in Figure 2). set the Guard switch to the Open position.
Resistance and DC Current Adjustment This adjustment calculates gain corrections for the resistance and DC current ranges. The DC Gain Adjustment must be performed prior to this adjustment because this adjustment relies on the values calculated by the DC Gain Adjustment. Note When offset compensated ohms is enabled (OCOMP ON command), the default delay time used by the multimeter for this adjustment is 50ms (50ms is the settling time used after the current source is switched on or off).
3. Set the front panel Terminals switch to Front. 4. Connect the resistance standard to the multimeter's front panel HI and LO Input and HI and LO Sense terminals as shown in Figure 3. If using a Guard wire (as shown in Figure 2), set the Guard switch to the Open position. If not using a Guard wire, set the Guard switch to the To LO position. 5. Execute the CAL command specifying the exact value of the resistance standard. For example, if the standard's value is 10.003kΩ, execute CAL 10.003E3.
the frequency and period measurement functions: adjusts the attenuator and amplifier high frequency response; and adjusts the Time Interpolator timing accuracy. Following this adjustment, the internal circuits have constant gain versus frequency. Equipment required: • • • • • • • Caution Keysight 3325A Synthesizer/Function Generator or equivalent. 3V Thermal Converter, Ballantine 1395A-3 or equivalent. 1V Thermal Converter, Ballantine 1395A-1 or equivalent. 0.5V Thermal Converter, Ballantine 1395A-0.
3. Set the synthesizer to deliver a 3V rms sinewave at a frequency of 100 kHz. Connect the synthesizer, the 3V thermal converter, and the multimeter as shown in Figure 4. Record the exact DC voltage measured by the multimeter on Line A of the Adjustment Record. Figure 4. Characterizing the Adjustment Setup 4. Set the synthesizer to deliver a 3V rms sinewave at a frequency of 2 MHz. Adjust the synthesizer's output voltage until the voltage displayed on the multimeter is within 0.
8. Set the synthesizer to deliver a 100mV rms sinewave at a frequency of 100 kHz. Replace the 1V thermal converter with the 0.5V thermal converter. Record the exact DC voltage measured by the multimeter on Line G of the Adjustment Record. 9. Set the synthesizer to deliver a 100mV rms sinewave at a frequency of 8 MHz. Adjust the synthesizer until the voltage displayed on the multimeter is within 0.2% of the voltage recorded on Line G.
14. Repeat step 13 for each synthesizer setting and SCAL command shown on Lines D through H on the Adjustment Record. 15. Disconnect all equipment from the multimeter. 16. Execute the ACAL AC command.
58A Adjustment Record Adjusted by: Date: 3458A serial number or other device ID number: Previous calibration number (CALNUM? command): multimeter) (record this number before adjusting the Adjustments performed:* 1. Front Terminal Offset Adjustment 2. Rear Terminal Offset Adjustment 3. DC Gain Adjustment (DCV Standard Uncertainty = 4. Resistance and DC Current Adjustment (Resistance Standard Uncertainty = 5.
Chapter 4 Performance Verification Tests Introduction This chapter contains performance tests designed to verify that the 3458A Multimeter is operating within the specifications listed in Appendix A. The Performance Tests are performed without access to the interior of the instrument. Required Equipment The equipment required for the performance tests is listed below.
Test Considerations This section discusses many of the major problems associated with low-level measurements. Many of the measurements in this manual fall into this category. It is beyond the scope of this manual to go into great detail on this subject. For more information, refer to a textbook dealing with standard metrology practices. • Test leads: Using the proper test leads is critical for low-level measurements.
• Ground Loops: Ground loops arise when the multimeter and the circuit under test are grounded at physically different points. A typical example of this is when a number of instruments are plugged into a power strip in an equipment rack. If there is a potential difference between the ground points, a current will flow through this ground loop. This generates an unwanted voltage in series with the circuit under test. To eliminate ground loops, ground all equipment/circuits at the same physical point.
General Test Procedure The following performance tests utilize a transfer standard DMM to precisely measure the verification source. The transfer standard DMM recommended is an 3458A option 002 (high stability) that is within a 90-day calibration. The verification source is first measured by the transfer standard DMM and then connected to the unit under test. The general test procedure is as follows: A. Performed one time prior to testing (Preliminary steps). 1.
Figure 6.
DC Voltage Performance Tests Required Equipment Preliminary Steps The following equipment or its equivalent is required for these performance tests. • Stable DC voltage source (Fluke 5700A or equivalent) • • • Transfer standard DMM (3458A Opt. 002 within 90 days of CAL) Low thermal short (copper wire) Low thermal test leads (such as Keysight 11053A, 11174A, 11058A) 1. Verify that the DC source is properly warmed up. 2. The 3458A requires a 4-hour warm-up period.
DC Voltage Function Offset Test The following procedure tests the offset voltage specification with the input terminals shorted. A low-thermal short must be used to minimize thermally induced errors. Also, you must allow five minutes before making the first measurement to allow for thermal stabilization of the range relays. 1. Connect a low thermal short across the front panel HI and LO input terminals of the DMM under test (see Figure 1 on page 23). 2.
of the DMM. 4. Set the range of the DMM to 100 mV. Wait five minutes for the DMM to thermally stabilize. 5. Set MATH NULL on the transfer standard DMM. 6. Execute Trig SGL to trigger the NULL reading. 7. Remove the EMF cable leads from the DMM and connect them to the HI and LO Input terminals 3458A under test. Connect the Guard terminal of the voltage source to the guard terminal of the 3458A under test. 8. Set the range of the 3458A under test to 100 mV.
Table 2. DCV Gain Performance Tests DC Gain Test Number 1 2 3 4 5 6 7 8a DMM Range 100 mV 1V 10 V 10 V 10 V 10 V 100 V 1000 V Source Output 100 mV 1V 1V -1 V -10 V 10 V 100 V 1000 V a.NOTE: After completing test 8, decrease the 1000V verification source output to 0V before disconnecting. 16. After all DC gain tests have been performed, calculate and record in the column provided.
Analog AC Voltage Performance Tests Required Equipment Preliminary Steps The following list of equipment is required to test the analog AC performance of the 3458A. • • • Stable AC voltage source (Fluke 5700A or equivalent). Transfer Standard DMM (3458A Opt. 002 within 90 days of Cal.) Shielded test leads terminated with dual banana plugs (such as Keysight 11000-60001). 1. Make certain that the AC source is properly warmed up. 2. The 3458A requires a 4 hour warm up period.
connection can be made using shielded test leads terminated with dual banana plugs. Refer to the general test procedure for test connections. 1. Connect the AC voltage source to the transfer standard DMM. 2. Set the range of the transfer standard DMM as specified in Table 3. 3. Set the range of the 3458A under test as specified in Table 3. 4. Set the AC source to the voltage level and frequency specified in Table 3 5.
points. 11. If any of the differences calculated are greater than the specified limits, refer to Chapter 3, "Adjustment Procedures", to make adjustments. DC Current Performance Tests Required Equipment Preliminary Steps The following equipment or its equivalent is required for these performance tests. • • • Stable DC current source (Fluke 5700A or equivalent) Transfer standard DMM (3458A Opt. 002 within 90 days of CAL) Low thermal test leads (such as Keysight 11053A, 11174A, or 11058A) 1.
DC Current Function Offset Test The following procedure tests the DC current offset specifications with the input terminals open. 1. Set the 3458A under test to the DC Current Function (DCI). 2. Set the range of the 3458A under test as specified in Table 4 3. Let the instrument sit for 5 minutes to allow the range relays to thermally stabilize. 4.
current source. 7. Connect the DC current source to the 3458A under test HI and LO input terminals. 8. Execute Trig and read the value as measured with the 3458A under test and record this value in the "Unit Under Test Reading" column of the DC CURRENT TESTS Test Card. 9. Repeat steps 1 through 8 for each of the remaining DC current test points as specified in Table 5. Table 5.
done, turn the instrument ON and allow it to warm up before proceeding. 3. The internal temperature of the 3458A under test must be within 5 degrees C of its temperature when last ohms adjusted. The current internal temperature can be obtained by executing TEMP?. Compare this temperature to adjustment temperature obtained by executing the command CAL? 60 and record both temperatures on the OHMS TESTS Test Card. 4.
4-Wire Ohms Function Offset Test (Rear Terminals) 4-Wire Ohms Function Gain Test 48 This procedure performance verifies the rear terminal ohms offset. 1. Connect a low thermal short across the rear terminals of the 3458A as shown for the front terminals in Figure 1 on page 23. 2. On the 3458A under test, select 4-wire ohms and the 10 Ω range by executing OHMF, 10. 3. Execute Trig and use the OHMS TESTS Test Card to record the offset reading. 4. Remove the short from the rear panel input terminals.
Table 6. OHMF Gain Test Number OHMF Gain Performance Tests Source and DMM Range Source Output 1 10 Ω 10 Ω 2 100 Ω 100 Ω 3 1 kΩ 1 kΩ 4 10 kΩ 10 kΩ 5 100 kΩ 100 kΩ 6 1 MΩ 1 MΩ 7a 10 MΩ 10 MΩ a. Note - At 10 MΩ, leakage current from the Sense leads introduce additional uncertainty in the measurement. This uncertainty, however, is accounted for in the published performance test limit.
Frequency Counter Accuracy Test 50 4. Configure the DMM under test as follows: -- FREQ -- Trig SGL -- FSOURCE ACDCV -- LEVEL 0,DC 1. Execute FSOURCE ACDCV (specifies the type of signal to be used as the input signal for frequency measurement). 2. Set the Frequency Standard to output a 1 volt p-p, 1 Hz sine-wave. Record the exact Frequency Standard Value on the FREQUENCY TESTS Test Card. Connect the output of the Frequency Standard to the HI and LO input terminals of the 3458A under test. 3.
PERFORMANCE TEST CARD - 1 YEAR LIMITS Keysight Model 3458A Digital Test Performed By Multimeter Serial Number Date DC VOLTAGE TESTS CAL? 59 TEMP? Difference - (must be less than 5 degrees C) Perform an ACAL DVC Test # 3458A Input 3458A Range Transfer Standard Reading Unit Under Test Reading Difference Limit (Std) Limit (Opt 002) OFFSET TESTS (NOTE: Math Null is Disabled) 1 Short 100 mV N/A N/A 000.00106 mV 000.00106 mV 2 Short 1V N/A N/A 0.00000106 V 0.
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PERFORMANCE TEST CARD - 1 YEAR LIMITS Keysight Model 3458A Digital Multimeter Test Performed By Serial Number Date AC VOLTAGE TESTS Perform an ACAL AC Test # 3458A Input 3458A Range Transfer Standard Reading Unit Under Test Reading Difference Limit (Std) Limit (Opt 002) 1 100 mV, 1KHz 100 mV 000.0250 mV 000.0250 mV 2 1 V, 1KHz 1V 0.000250 V 0.000250 V 3 1 V, 1KHz 10 V 00.00096 V 00.00096 V 4 10 V, 20 Hz 10 V 00.01338 V 00.01338 V 5 10 V, 1KHz 10 V 00.00250 V 00.
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PERFORMANCE TEST CARD - 1 YEAR LIMITS Keysight Model 3458A Digital Multimeter Test Performed By Serial Number Date DC CURRENT TESTS CAL? 60 TEMP? Difference - (must be less than 5 degrees C) Perform an ACAL OHMS Test # 3458A Input 3458A Range Transfer Standard Reading Unit Under Test Reading Difference Limit (Std) Limit (Opt 002) OFFSET TESTS (NOTE: Math Null is Disabled) 1 Open 100 µA N/A N/A 000.00095 µA 000.00095 µA 2 Open 1 mA N/A N/A 0.0000065 mA 0.
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PERFORMANCE TEST CARD - 1 YEAR LIMITS Keysight Model 3458A Digital Multimeter Test Performed By Serial Number Date OHMS TESTS CAL? 60 TEMP? Difference - (must be less than 5 degrees C) Perform an ACAL OHMS Test # 3458A Input 3458A Range Transfer Standard Reading Unit Under Test Reading Difference Limit (Std) Limit (Opt 002) 2-Wire Function Offset Test 1 Short 10 Ω N/A N/A 00.25007 Ω 00.25007 Ω N/A N/A 00.00007 Ω 00.
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PERFORMANCE TEST CARD - 1 YEAR LIMITS Keysight Model 3458A Digital Multimeter Test Performed By Serial Number Date FREQUENCY TESTS Test # 3458A Input 3458A Range 1 1 Hz N/A 2 10 MHz N/A Frequency Standard Value Unit Under Test Reading Difference Limit (Std) Limit (Opt 002) ±0.000500 Hz ±00.00100 MHz ±0.000500 Hz ±00.
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Chapter 5 Command Summary This section provides an alphabetical summary of commands that are used in calibrating the 3458A (adjustments or performance verification). Detailed command reference pages for each command are also included in this chapter. ACAL Autocal. Instructs the multimeter to perform one or all of its automatic calibrations. CAL Calibration. Calibrates the internal 7V reference to an external 10V standard (CAL 10) followed by an ACAL DCV.
ACAL Description Syntax Autocal. Instructs the multimeter to perform one or all of its automatic calibrations.
Example OUTPUT 722;"ACAL ALL,3458" !RUNS ALL AUTOCALS, SECURITY CODE IS 3458! (FACTORY SECURITY CODE SETTING) Chapter 5 Command Summary 63
CAL Description Syntax Calibration. Calibrates the internal 7V reference to an external 10V standard (CAL10) and does the equivalent of ACAL DCV. Also calibrates the internal 40 K reference to an external 10 K standard (CAL 10E3) and does the equivalent of ACAL OHMS. Alternate CAL standard values can be used as described in the first remark. It also calculates the offset for the front and rear terminals (CAL 0).
CAL? Description Syntax Calibration query. Returns a string containing one of four values for the calibration constant specified; the initial (nominal) value, low limit, high limit, or actual value of the specified constant. The returned string also contains a description of the constant. This command is in the full command menu; it is not in the short command menu. CAL? const_id [,cal_item] cal_item Specifies which of the four calibration constant values is to be returned.
66 22 23 24 25 26 27 28 29 30 ohm zero rear 10 ohm zero rear 100 ohm zero rear 1 K ohm zero rear 10 K ohm zero rear 100 K ohm zero rear 1M ohm zero rear 10M ohm zero rear 100M ohm zero rear 1G 31 32 33 34 35 36 37 38 39 ohmf zero front 10 ohmf zero front 100 ohmf zero front 1 K ohmf zero front 10 K ohmf zero front 100 K ohmf zero front 1M ohmf zero front 10M ohmf zero front 100M ohmf zero front 1G 40 41 42 43 44 45 46 47 48 ohmf zero rear 10 ohmf zero rear 100 ohmf zero rear 1 K ohmf zero rear 10 K oh
67 68 69 dci zero rear 10 mA dci zero rear 100 mA dci zero rear 1A -ACAL OHMS 70 71 72 73 74 dcv gain 100 mV dcv gain 1V dcv gain 10V dcv gain 100V dcv gain 1 KV -ACAL DCV 75 76 77 78 79 80 81 82 83 ohm gain 10 ohm gain 100 ohm gain 1 K ohm gain 10 K ohm gain 100 K ohm gain 1M ohm gain 10M ohm gain 100M ohm gain 1G -ACAL OHMS 84 85 86 87 88 89 90 91 92 ohm ocomp gain 10 ohm ocomp gain 100 ohm ocomp gain 1 K ohm ocomp gain 10 K ohm ocomp gain 100 K ohm ocomp gain 1M ohm ocomp gain 10M ohm ocomp gai
68 107 low aperture 108 109 110 111 112 high aperture high aperture slope .01 PLC high aperture slope .1 PLC high aperture null .01 PLC high aperture null .
151 152 153 154 155 156 157 158 overload ohm ocomp 100 overload ohm ocomp 1 K overload ohm ocomp 10 K overload ohm ocomp 100 K overload ohm ocomp 1M overload ohm ocomp 10M overload ohm ocomp 100M overload ohm ocomp 1G 159 160 161 162 163 164 165 166 underload dci 100 nA underload dci 1 µA underload dci 10 µA underload dci 100 µA underload dci 1 mA underload dci 10 mA underload dci 100 mA underload dci 1A 167 168 169 170 171 172 173 174 overload dci 100 nA overload dci 1 µA overload dci 10 µA overload d
70 196 197 198 199 200 201 202 flatness dac 100 mV flatness dac 1V flatness dac 10V flatness dac 100V flatness dac 1 KV level dac dc 1.2V level dac dc 12V 203 204 level dac ac 1.
241 acv ana offset 1 KV 242 243 rmsdc ratio sampdc ratio 244 aci gain 245 246 freq gain attenuator high frequency dac 247 amplifier high frequency dac 10 mV 248 amplifier high frequency dac 100 mV 249 amplifier high frequency dac 1V 250 amplifier high frequency dac 10V 251 amplifier high frequency dac 100V 252 amplifier high frequency dac 1 KV 253 interpolator -SCAL Remarks Related Commands: ACAL, CAL, SCAL Example The following two program examples query the calibration constants.
60 70 80 90 100 110 120 72 PRINT "CONST =", N OUTPUT 722;"QFORMAT ALPHA" OUTPUT 722;"CAL?";N,T ENTER 722; A$ PRINT A$ NEXT N END Chapter 5 Command Summary
CALNUM? Description Syntax Remarks Calibration Number Query. Returns a decimal number indicating the number of times the multimeter has been adjusted. CALNUM? • The calibration number is incremented by 1 whenever the multimeter is • • • Example unsecured and adjusted. If autocal is secured, the calibration number is also incremented by 1 whenever an autocal is performed; if unsecured, autocal does not affect the calibration number.
CALSTR Description Syntax Calibration String (remote only). Stores a string in the multimeter's nonvolatile calibration RAM. Typical uses for this string include the date or place of calibration, technician's name, last CALNUM value, or the scheduled date for the next calibration. CALSTR string[,security_code] string This is the alpha/numeric message that will be appended to the calibration RAM. The string parameter must be enclosed in single or double quotes.
REV? Description Syntax Example Revision Query. Returns two numbers separated by a comma. The first number is the multimeter's outguard firmware revision. The second numberis the inguard firmware revision.
SCAL Description Service Calibration. Adjusts the AC sections of the instrument. Calculates the corrections to accurately measure frequency and adjusts the ac ranges. The SCAL command is located in the full command menu. Note The SCAL command is used in the AC adjustment procedure of Chapter 3 and the procedure must be performed in the order specified. Syntax SCAL value [,security_code] value Specifies the value of the adjustment source that will be used to do the service adjustment of the multimeter.
SECURE Description Syntax Security Code. Allows the person responsible for adjustment to enter a security code to prevent accidental or unauthorized adjustment or autocalibration (autocal). SECURE old_code, new_code [,acal_secure] old_code This is the multimeter's previous security code. The multimeter is shipped from the factory with its security code set to 3458. new_code This is the new security code. The code is an integer from -2.1E-9 to 2.1E9.
Disabling Security OUTPUT 722;"SECURE 3458,0" !DISABLES SECURITY FOR ADJUSTMENT AND AUTOCAL 78 Chapter 5 Command Summary
TEMP? Description Syntax Remarks Temperature Query. Returns the multimeter's internal temperature in degrees Centigrade. TEMP? • Monitoring the multimeter's temperature is helpful to determine when to perform autocalibration.
TEST Description Syntax Remarks Causes the multimeter to perform a series of internal self-test. TEST • Always disconnect any input signals before you run self-test. • • • Example 80 If you leave an input signal connected to the multimeter, it may cause a self-test failure. If a hardware error is detected. the multimeter sets bit 0 in the error register and a more descriptive bit in the auxiliary error register. The display's ERR annunciator illuminates whenever an error register bit is set.
Appendix A Introduction Specifications The following examples illustrate the error correction of auto-calibration by computing the relative measurement error of the 3458A for various temperature conditions. Constant conditions for each example are: The 3458A accuracy is specified as a part per million (ppm) of the reading plus a ppm of range for dcV, Ohms, and dcl. In acV and acl, the specification is percent of reading plus 10 V DC input percent of range.
1 / DC Voltage 1. Additional error from Tcal or last ACAL ± 1 º C. DC Voltage 2. Additional error from Tcal ±5º C 3. Specifications are for PRESET, NPLC 100. 4. For fixed range (> 4 min.), MATH NULL and Tcal ±1ºC. 5. Specifications for 90 day, 1 year and 2 year are within 24 hours and ±1º C of last ACAL; Tcal ±5ºC, MATH NULL and fixed range. Range Full Scale Maximum Resolution 100 mV 1V 10 V 100 V 1000 V 120.00000 1.20000000 12.0000000 120.000000 1050.
Reading Rate (Auto-Zero Off) Selected Reading Rates 1 Readings / Sec A-Zero NPLC Aperture Digits Bits A-Zero On Off 0.0001 0.0006 0.01 0.1 1 10 100 1000 1.4 µs 10 µs 167 µs2 1.67 ms2 16.6 ms2 0.166 s2 4.5 5.5 6.5 6.5 7.5 8.5 8.5 8.5 16 18 21 21 25 28 28 28 100,000 3 50,000 5,300 592 60 6 36/min 3.6/min 4,130 3,150 930 245 29.4 3 18/min 1.8/min 1. For PRESET; DELAY 0; DlSP OFF; OFORMAT DINT; ARANGE OFF. 2. Aperture is selected independent of line frequency (LFREQ).
2 Accuracy1 (ppm of Reading + ppm of Range) Range 24 Hour 2 5+3 3+3 2+0.2 2+0.2 2+0.2 10+1 50+5 500+10 0.5%+10 10 Ω 100 Ω 1 kΩ 10 kΩ 100 kΩ 1 MΩ 10 MΩ 100 MΩ 1 GΩ 90 Day3 15+5 10+5 8+0.5 8+0.5 8+0.5 12+2 50+10 500+10 0.5%+10 1 Year3 15+5 12+5 10+0.5 10+0.5 10+0.5 15+2 50+10 500+10 0.5%+10 2 Year3 20+10 20+10 15+1 15+1 15+1 20+4 75+10 0.1%+10 1%+10 1. Specifications are for PRESET; NPLC 100; OCOMP ON; OHMF. 2. Tcal ± 1°C. 3.
3 / DC Current DC Current (DCI Function) Range 100 nA 1 µA 10 µA 100 µA 1 mA 10 mA 100 mA 1A Full Scale 120.000 1.200000 12.000000 120.00000 1.2000000 12.000000 120.00000 1.0500000 Maximum Shunt Burden Resolution Resistance Voltage 1 pA 1 pA 1 pA 10 pA 100 pA 1 nA 10 nA 100 nA 545.2 kΩ 45.2 kΩ 5.2 kΩ 730 Ω 100 Ω 10 Ω 1Ω 0.1 Ω 0.055 V 0.045 V 0.055 V 0.075 V 0.100 V 0.100 V 0.250 V <1.
4 / AC Voltage General Information The 3458A supports three techniques for measuring true rms AC voltage, each offering unique capabilities. The desired measurement technique is selected through the SETACV command. The ACV functions will then apply the chosen method for subsequent measurements. The following section provides a brief description of the three operation modes along with a summary table helpful in choosing the technique best suited to your specific measurement need.
AC Accuracy (continued): 24 Hour to 2 Year (% of Reading + % of Range) Range 10 mV 100 mV – 10 V 100 V 1000 V ACBAND >2 MHz 45 Hz to 100 kHz 100 kHz to 1 MHz 1 MHz to 4 MHz 4 MHz to 8 MHz 8 MHz to 10 MHz 0.09 + 0.06 1.2 + 0.05 7 + 0.07 20 + 0.08 0.09 + 0.06 2.0 + 0.05 4 + 0.07 4 + 0.08 15 + 0.1 0.12 + 0.002 0.3 + 0.01 Transfer Accuracy Range % of Reading 100 mV – 100 V (0.002 + Resolution in %)1 Conditions • Following 4 Hour warm-up • Within 10 min and ±0.
High Frequency Temperature Coefficient Maximum Input For outside Tcal ±5°C add the following error. (% of Reading)/°C HI to LO LO to Guard Guard to Earth Volt – Hz Product Frequency Range 2 – 4 MHz 4 – 10 MHz 10 mV – 1 V 0.02 0.08 10 V – 1000 V 0.08 0.08 Rated Input ±1000 V pk ±200 V pk ±500 V pk 1x108 Non-Destructive ±1200 V pk ±350 V pk ±1000 V pk Analog Mode (ACV Function, SETACV ANA) Range Maximum Full Scale Resolution 10 mV 100 mV 1V 10 V 100 V 1000 V 12.00000 120.0000 1.200000 12.00000 120.
Reading Rates 1 1. Sec / Reading ACBAND Low ≥10 Hz ≥1 kHz ≥10 kHz NPLC 10 1 0.1 ACV 1.2 1 1 For DELAY–1: ARANGE OFF For DELAY 0; NPLC .1 , unspecified reading rates of greater than 500/Sec are possible. ACDCV 1 0.1 0.02 Settling Characteristics For first reading or range change error using default delays, add .01% of input step additional error. The following data applies for DELAY 0.
AC + DCV Accuracy (ACDCV Function) For ACDCV Accuracy apply the following additional error to the ACV accuracy. (% of Range). DC ≤10% of AC Voltage ACBAND ACBAND Temperature Range ≤ 2 MHz >2 MHz Coefficient 1 10 mV 0.09 0.09 0.03 100 mV–1 kV 0.008 0.09 0.0025 DC >10% of AC Voltage ACBAND ACBAND Temperature ≤ 2 MHz >2 MHz Coefficient1 0.7 0.7 0.18 0.07 0.7 0.025 1. Additional Errors Apply the following additional errors as appropriate to your particular measurement setup.
5 / AC Current AC Current (ACI and ACDCI Functions) Range 100 µA 1 mA 10 mA 100 mA 1A Maximum Resolution 100 pA 1 nA 10 nA 100 nA 1 µA Full Scale 120.0000 1.200000 12.00000 120.0000 1.050000 Shunt Resistance 730 Ω 100 Ω 10 Ω 1Ω 0.1 Ω Burden Voltage 0.1 V 0.1 V 0.1 V 0.25 V < 1.5 V Temperature Coefficient 1 (% of Reading + % of Range) / °C 0.002+0 0.002+0 0.002+0 0.002+0 0.002+0 1. Additional error beyond ±1°C, but within ±5°C of last ACAL. 2.
Settling Characteristics For first reading or range change error using default delays, add .01% of input step additional error for the 100 µA to 100 mA ranges. For the 1 A range add .05% of input step additional error. The following data applies for DELAY 0. Function ACBAND Low ≥10 Hz ACI ACDCI DC Component DC < 10% AC Settling Time 0.5 sec to 0.01% DC > 10% AC 0.9 sec to 0.01% 0.5 sec to 0.01% 0.08 sec to 0.01% 0.015 sec to 0.
7 / Digitizing Specifications General Information The 3458A supports three independent methods for signal digitizing. Each method is discussed below to aid in selecting the appropriate setup best suited to your specific application. DCV Standard DCV function. This mode of digitizing allows signal acquisition at rates from 0.2 readings / sec at 28 bits resolution to 100k readings / sec at 16 bits. Arbitrary sample apertures from 500 ns to 1 sec are selectable with 100 ns resolution.
Dynamic Performance 100 mV, 1 V, 10 V Ranges; Aperture = 6 µs Test DFT-harmonics DFT-spurious Differential non-linearity Signal to Noise Ratio Input (2 x full scale pk-pk) 1 kHz 1 kHz dc 1 kHz Result < –96 dB < –100 dB < 0.
8 / System Specifications Function-Range-Measurement The time required to program via GPIB a new measurement configuration, trigger a reading, and return the result to a controller with the following instrument setup: PRESET FAST; DELAY 0; AZERO ON; OFORMAT SINT; INBUF ON; NPLC 0.
9 / Ratio Type of Ratio 1 DCV / DCV ACV / DCV ACDCV / DCV 1. Ratio = (Input) / (Reference) Reference: (HI Sense to LO) – (LO Sense to LO) Reference Signal Range: ±12 V DC (autorange only) Accuracy ± (Input error + Reference Error) Input error = 1 × Total Error for input signal measurement function (DCV, ACV, ACDCV) Reference error = 1.
11 / General Specifications Operating Environment Temperature Range: 0°C to 55°C Operating Location: Indoor Use Only Operating Altitude: Up to 2,000 Meters Pollution Rating: IEC 664 Degree 2 Warranty Period One year Operating Humidity Range up to 95% RH at 40°C Input Limits Input HI to LO: 300 Vac Max (CAT II) Physical Characteristics 88.9 mm H x 425.5 mm W x 502.9 mm D Net Weight: 12 kg (26.5 lbs) Shipping Weight 14.8 kg (32.5 lbs) IEEE-488 Interface Complies with the following: IEEE-488.
98 Appendix A Specifications
Appendix B Electronic Calibration of the 3458A (Product Note 3458A-3) A voltmeter has four basic functional blocks. The input signal must first pass through some type of signal conditioner. For a DC input voltage, the signal conditioner may consist of an attenuator for the higher voltage ranges and a DC amplifier for the lower ranges. If the input signal is an AC voltage, an RMS converter changes the AC signal to an equivalent DC value.
Saving Calibration Time and Money The increasing accuracy required of today's instrumentation tends to increase complexity and cost of maintaining calibration of these instruments. In an effort to reduce the cost and complexity of calibration, the 3458A Multimeter reduces the number of external reference standards required for calibration. All functions and ranges require only one external DC voltage standard and only one external resistance standard.
Measurements using a Josephson junction standard confirm linearity of the analog-to-digital converter design. These measurements reveal integral linearity below 0.1 parts per million and differential linearity of 0.02 parts per million. This performance, incidentally, is comparable to a Kelvin-Varley divider. Other multimeters use this approach to removing offset errors. The 3458A Multimeter simply makes improvements by using more stable components, again minimizing time and environmental errors.
The user enters the exact value of the external 10 V DC voltage standard (for example, "CAL 10"). The following sequence, performed automatically by the 3458A Multimeter, determines gain constants for all ranges: The lower ranges use amplifiers to condition the input for the 10 V full-scale analog-to-digital converter. Each amplifier used requires a gain constant, GA, to adjust normal readings. The following process determines these constants. 1. Measure the external "10 V" standard on the 10 V range. 5.
Resistance and DC Current Adjustments Calibration of all resistance (nine ranges from 10 Ω to 1 GΩ) and DC current ranges (eight ranges from 100 nA to 1 A) requires only one external resistance standard. Resistance is measured by applying a known current through the unknown resistance and measuring the voltage across it. Current is measured by applying the unknown current through a known shunt resistor and measuring the voltage across it.
The 3458A Multimeter produces the required step input voltage. Then, its analog-to-digital converter samples the attenuator output. These measurement results determine constants used to control the output of the flatness adjusting DAC. Control of the DAC output effectively changes the resistance in one leg of the attenuator to produce the desired maximally flat response. Calibration constants are separately determined for each AC range. AC converters normally have turnover errors.
Summary Externally Derived Calibration Constants Electronic internal calibration of the 3458A Multimeter simplifies and shortens the calibration time, while maintaining accuracy and traceability. This multimeter removes all drift errors, with the exception of the internal reference standard drift errors. As a result, the scheme relies on the excellent stability of the reference voltage and resistor, and superb linearity of the analog to-digital converter.
106 Appendix B Electronic Calibration of the 3458A (Product Note 3458A-3)
This information is subject to change without notice. © Keysight Technologies 1988 - 2014 Edition 7, August 2014 *03458-90017* 03458-90017 www.keysight.
