Hewlett-Packard 3478A multimeter Operator's manual

IMPORTANT NOTICE Most -hp- service offices in the United States are NOT authorized to service andrepair 3478A DMM's. Contact your local -hp- sales office for specific information on where to send the instrument for repair. Outside of the United States, repair service may be obtained at your local -hp- service center. oy e ra uu Hy ¢ ^^ Ary changes made iminstruments ) ing will be found in a "Manual Changes’ supplement suppl this manual. Be sure to examine this supplement, if one exists for this manual, for any changes which apply to your instrument and record these changes in the manuái. Printed: February 1983 To help minimize the possibility of electrical fire or “shock hazards, do not expose this instrument to rain “or excess moisture. + x ©Copyright Hewlett-Packard Company 1981 P.O. Box 301, Loveland, Colorado, 80537 U.S.A Manual! Part No. 03478-90005 Microfiche Part No. 03478-90055 mrp EL 2. . ATA AA] SEL Ea E a MN E zur 4 \ Fev — ey — A 0 3468A/B/3478A 0) Newer 3468A/B/3478A Service Card A Service Card ; Refer to Chapter V of your Operators Manual to diagnose a Refer to Chapter V of your Operators Manual to diagnose a 3468A/B/3478A malfunction, The warranty period for your multimeter 3468A/B/3478A malfunction. The warranty period for your multimeter and/or accessory is one year from date of purchase. Should service _ and/or accessory is one year from date of purchase. Should service be required, please return this card with your 3468A/B/3478A instru- be required, please return this card with your ЗАБВА/В/ЗАТВА instrument protectively packaged {refer to Chapter V of the Operators ment protectively packaged (refer to Chapter V of the Operators Manual) to avoid in-transit damage. Such damage is not covered under ; Manual} to avoid in-transit damage. Such damage is not covered under warranty. | warranty. Inside the U.S.A. Attention: HP Service repair in the U.S.A. for the 3468A/B and 34 78A : Attention: HP Service repair in the U.S.A. for the 3468A/B and 3478A is only available at the following location: HEWLETT Г; PACKARD ; Hewlett-Packard Hewlett-Packard | instrument Service Center | | Instrument Service Center P.0. Box 7922/6940 Middlefield P.O. Box 79221690 Middiefieid Mountain View, CA 94042 Mountain View, CA 94042 We advise that vou insure your multimeter and use priority {AIR} mail for distances greater than 300 miles to minimize transit times. Ali units will he returned by the fastest practical means. A Outside the U.S.A. Return your unit to the nearest designated Hewlett- "Packard Sales and Service Office. Check the back of your Operators Manual or Service Manual for the address. % Rid HOE OF OE OE + # XX EE NN oA НХ хх хх нон он он ох о Кой о * ой он нон ох хо + # + 4 + * HR Preferred method of payment for out-of-warranty repairs is a purchase order for companies with established Hewlett-Packard credit . (Include copy of purchase order with shipment.) We advise that ycu insure your multimeter and use priority (AIR) mail for distances greater than 300 miles to minimize transit times. All units will be returned by the fastest practical means, Outside the U.S.A. Return your unit to the nearest designated Hewlett Packard Sales and Service Office. Check the back of your Operators Manual! or Service Manual for the address. ERK EEE KKH HEE EER ER EERE RAE RE REFER KEELER FETE RAE NA Preferred method of payment for out-of-warranty repairs is a purchase order for companies with established Hewlett-Packard credit . {Include copy of purchase order with shipment.) PO, Number Model No. | Serial No. - P.O. Number - Model No, | “Serial No. Ш Authorized Signature Authorized Signature Service Information This card must be completed and returned with your unit. Company Name Bate Company Contact (Name) | | Phone a Sireet Address City State Zip Instrument Serial Number What Is the Problem Area? CL} Self-Test Fail Li Rechargeable Battery Dl Accuracy (specify function (3468A/8 only) and range) EJ HP-IL (3468A/B only) * Li Noise {specify function and L] HP-1B {3478A only) range) El Unable to calibrate Dl Display/Keyboard terror message occurs) С) Intermittant problem Ei Other {please describe below) О Application” Describe Problem *Before sending the 3468A/8 in for an HP-IL problem, be sure that it is the instrument causing the problem. This card must be completed and returned with your unit, Service Information % O0 65 00 Company Name Date Company Contact (Name) Phone a Street Address City State | Zip | Instrument Serial Number What Is the Problem Area? С Self-Test Fail Rechargeable Battery Accuracy (specify function (3468A/B only) and range) 1 HP-IL (3468A/B only)" Noise {specify function and 1 HP-IB (3478A only) range) Li Unable to calibrate Display/Keyboard {error message occurs) Intermittant problem L.3 Other (please describe below) Г) Application * Describe Problem # i i “i * Before sending the 34GBA/8 in for an HP-R. problem, be sure that itis the instrument causing the problem, TABLE OF CONTENTS Chapter Page Chapter Page „Fi. MEET THE 3478A... 1214104544 610 00 1 Hi, REMOTE PROGRAMMING (Contd)...... 35 ) Introduction ....... e *eevva. aaa 1 Trying Out a Command. ............. 35 | How to Use This Manual... ........... 2 Addressing . «ov vc vive vee 36 Simplified Operation. .............. 5/6 Sending Instructions to the 3478A...... 37 Home Commands. .. . .. «vou vv ono 39 Chapter Page Programming Hints. . . . ...... oc... 40 i, USINGTHE3478A... re... era 7 Receiving Data from the 3478A........ 41 Introduction ..... ... 1 aaa 7 3478A Bus Capabilities are „0.4.42 Detailed Operating instructions. ......... 7 CLEAR i ie 43 Operating Characteristics. ...... em... 7 Examples . ......o.oemereear kee 43 AUTOZERO ..... RK KK 8 Comments ......coe.-..e.. ... ... 43 What is Autozero?. ........ +... «. 8 LOCAL. 1112404 8442 144 40 0 444400 44 How it Affects Measurements.......8 Examples .......44 2440000 МЕ 44 CALIBRATE 1 1112444444 4 4 1 1444 0 10 Comments ... 14244 44e 8 442000 44 What is Electronic Calibration?...... 10 LOCAL НОСКОНТ................ 44 Calibrate Enable. ............... 10 Example .. 1.442804 4 844 844000 44 CURRENT ..... eee ee 11 Comments ... 112440000400 0 0 44 Meastiring Current. ............. 11 REMOTE E 45 DISPLAY 11224 4 424 44 64 6e a a 11e 0 12 Examples ......4 442840 2044506 45 How itis Used. ............... 12 Comments . . «ov vv von vey 45 Normal .......... nea deco 12 REQUIRE SERVICE (SRO). 2.244400 46 Message...... naaa ere dd 13. How to н5е ОВО... ............. 46 User Generated Message.......... 15 Status Register and Status Byte. .... 47 Changing the Number of Digits Settingrthe SRQ Mask. . ....... 47 Displayed . . ....... cov, 15 POLL. E 50 Annunciators. .. 240040254400 17 Example ......oe.eneverreoe 50 OPTIMIZING READING RATES. ....... 18 Comments ... 4244480480 10446 50 Why Optimize?............... 18 TRIGGER 1.121014 4 4 4 4 44 6 0 4 48446 53 Your Signal Environment. . . ....... 18 Examples ......2 444844 4004000 53 A ) Integration Times. . ............. 18 Comments «ov vv ve vv ee 53 Lo Autozeto. . .... ee cede arena 19 Topics in Advanced Programming aaa 54 | | Other Factors Influencing the TEMPERATURE MEASUREMENTS. ..., 54 Reading Rate. . ........ co... 19 EXTENDED OHMS... .. museo 55 RANGING. ..... iis 20 dBm MEASUREMENTS. ........... 56 What About Ranging?. . .......... 20 MAXIMUM READING RATE. . ....... 57 Reading the Display... .......... 20 STATUS BYTECOMMAND. ......... 58 Autorange....... TUTTI 2-1 347-8 A-Programming-Commands... vr. BS Manual Ranging. .............. 22 REAR PANEL. ......... 4 4 0446 23 Chapter Page What is on the Rear Panel?. . ....... 23 IV. OPERATORS MAINTENANCE. .......—.. 63 - The Rear Panel Switches... ....... 23 Introduction ......... remera. 63 ; RESISTANCE MEASUREMENTS...... 25 Accessories. ........eeorecra dee 63 | Measuring Resistance. ........... 25 Initial Inspection... 222042440414 0 6 64 How Resistances are Measured. . . . .. 25 Preparation for Use. ... 112440004006 64 Other Considerations............28 Safety Considerations. .. . 84401200 66 TEST/RESET. . .... essere... 29 Environmental Requirements. ......... 67 What it Does. . ... ese ear о 29 Specifications . ..... co a ie 67 TRIGGER MODES..... esmas 30 Interface Connections. . ..... aaa 67 Whatis Triggering?. ...... e. —r.e.. 30 Fuse Replacement. ................ 68 Trigger indicator. ........ e... 30 In Case of Trouble. 1... 1.244444 445400 70 VOLTAGE MEASUREMENTS... ...... 32 Warranty Information. . .... oe. ee. 73 » Measuring Voltages....... eme. 32 How to Obtain Repair Service. . ........ 74 4 VOLTMETER COMPLETE. ........ —.. 34 Serial Number. ..... eo me nenxrorear 74 What is Voltmeter Complete?. ...... 34 General Shipping instructions. . .. ....e. 74. Using the Voltmeter Complete Pulse. . 34 Further Considerations. ............. 75 | Verification Program and Flow Chart. .... 76 Chapter D Hi. REMOTE PROGRAMMING. .......... ‚ 35 APPENDICES introduction .. .. 124024 44004046 ".. 35 A 114 LL 4 4 4 4 4 4 4 44 4 4 44 ee ea 83 Te DE 35 BL 11104 4 4 8 4 4 4 4 4 8 4 4 4 4 84 4 4 44450 91 LiST OF ILLUSTRATIONS Figure Page 2-1. Current Measurements. ........... 11 2-2. Autorange Hysteresis. ........... . 22 2-3. 3478A Rear Panel and Switches. , . . . 24 2-4. Resistance Measurements. ...... 2227 2-5. Voltage Measurements. .......... 1 33 2-6. Using Voltmeter Complete. ......... . . 34 3-1. Sending Instructions. . ........... 0 37 3-2. Instruction Example. ............ 38 3-3. Status Register... ............. 47 3-4. Status Byte and SRQ Mask, . ........ 47 3-5. Status Byte. . ................. 50 4-1. Power Cables. ....... и ии е, 65 4-2. Typical HP-IB System Interconnection. . . . 68 4-3. 347BA Address Codes. ........... 69 A-1. HP-IB Connector... .... | Cee à 83 A-2. Interface Connection and Bus Structure. .. 84 LIST OF TABLES Table Page 2-1. Operating Characteristics. . .......... 7 2-2. 3478A Messages. . .............. 0 13 2-3. Annunciators. . LL... LL. 17 2-4. Valid 3478A Ranges. . ............ 21 2-5. Nominal currents through Unknown Resistance. .................. .. 25 2-6. Self Test Error Messages. . . . .... ee 29 3-1. Home Commands. ............... 38 4-1. Accessories. . . . . Lr rh ete eee eee à 63 4-2. Line Voltage Options. . . ........... 64 4-3. Specifications . ............... 80 А-1. 3478A Device Capability, . . ,......... 87 A-2. HP-IB Worksheet, . .....,........ 88 Chapter | Meet The 3478A Introduction Your new 3478A is a fully programmable HP-IB* digital multimeter. In an automatic test or on the bench, the 3478A offers 3 1/2 to 5 1/2 digit resolution for measuring de volts, true RMS ac volts, 2- and 4- wire ohms, and de and RMS ac current. The 3478A offers de voltage performance from 100 nanovolt sensitivity up to 300 volts (ful scale), true RMS capability up to 300 kHz, and resistance measurements from 10040 sensitivity to 30M (full scale). its dc and true AMS ac current measuring capability is from ÎuÂ sensitivity up to 3A. The fast autorange capability of the 3478A allows you 10 make measurements over a wide dynamic range without sacrificing throughput rates. " By selecting the number of digits displayed and using the autozero feature, the 3478A allows you flexibility in measurement speed and accuracy. Up to 71 readings per second can be made with the 3478A in the 3 1/2 digit mode. The 3478A has a fast trigger mode which lets you bypass the built-in settling time delay to make fast true RMS ac measurements in systems applications. The alphanumeric Liquid Crystal Display (LCD) gives you measurement units as part of the reading for easy-to-read, unambiguous answers. The HP-IB talk, listen, remote, and SRQ status information is also available with+tCD-annunciators.—Fhe SRO button can be used to flag or interrupt your computer from the front panel of the 347 8A. Other system features of the 3478A include the Voltmeter Complete signal and External Trigger input, both available on the rear panel, to synchronize with scan- ners or to other external devices. The switchable front/rear inputs let you easily connect to the 3478A for either bench or systems operation. The systems package of the 3478A offers convenient rack mounting in a system. Furthermore, to lower your cost of ownership, the 3478A is calibrated elec- tronically, either manually from the front panel or remotely in an automatic calibration system. There are no internal adjustments and the calibration of all functions is done without the removal of covers. The self-test function verifies most of the internal circuitry of the 3478A for an indication of the proper operation of the multimeter. * HP.IB {Hewlett-Packard Interface Bus) is Hewlett-Packard's implementation of IEEE Standard 483-1978 and ANSI MC1.1. How to Use This Manual as a complete reference document for using the 3478A as a solution to your Measurement needs. It covers both bench use and remote Programming, Maintenance Procedures, such as installation, were Intentionally placed later in the manual -Chapter 4 - because this information is seldom referred to. If, however YOU have just received your 3478A vou May want to read that information. A Familiarize Yourself with the 3478A by looking through this Manual, The best way to feel at ease with the instrument is to sit down with this Manual and the 3478A and key in the examples shown, It won't take long to become familiar with the instrument and its many features. | Using the 3478A, Chapter | SENSE ol Chapter II begins where Chapter | | Hi closes by discussing each function and s00v=; feature of the 3478A in much more O — ) detail. This Chapter also Covers topics sax A suuNT= 19 Such as Optimizing reading rates, alter. C + nate triggering modes, the rear panel мы near | ; > я = 3A/250V CiSCUIT features, and the display. The topics FUSE 3 nene | are alphabetically arranged for easy Ш v SC OR AC reference. Most of the information in ENT this chapter will prove to be very helpful when YOU are remote programming the 3478A, SOURCE Remote Programming, (6 1 TEMPERATURE MERSUREMENT - Chapter || =; 1 WITH TYPE 44887 THERHISTOR 76 ! -HP- ES VERSION — 4 OUTPUT 722, ¿FR If your needs are in the area of remote == 3 E GUTP 3} IE , = g3= 0900009941 programming the 3478A, then Chapter a D27= 06023595 AE _ su Gi= 001296 HI is where you need to look for pro- Sa ENTER 723 ; В ramming information.’ Numero X- 1 G0 Q4=LOGCR) gra 9 a Umerous e 118 P=i/C61+D4KXCO2+04X04kQ3)>-27 amples are given to enhance the pro- 2.16 . . \ 128 DISP P gramming discussion. At the end of 138 COTO 90 . 4: 145 END - this Chapter are several application program examples designed to solve frequently encountered measurement a problems. Remember that you will want to read Chapter I! prior to beginning Chapter ti. Operators Maintenance, Chapter IV Operators maintenance information is found in Chapter IV. This chapter ad- Е — 34788 VERIFICATION PROGRAH i i ] r com- # . REMOVE RLL INSTRUMENTS - | dresses installation procedu es, a i FROM THE BUS EXCEPT 2780. | plete table of specifications, what to № . BO NOT PRESS ANY 3I478A a , | | KEYS DURING THIS TEST ВЕ do if you suspect problems with the M UNTIL INSTRUCTED TQ BD Sb. . E . REMOVE ALL INPUT CABLES 3478A, and many other items of @ FROM TRE 24788. special interest to the operator. TEST PROGRESS IS SHOWN ON THE DISPLAY, ERRORS ARE NOTED CN | . - THE PRINTER. PRESS ECONTI KEY Most -hp- service offices in the United # PEA TO BEGIN. . States are NOT authorized to service E - and repair 3478A DMM's. Notify your Ш | т О local -hp- sales office for specific infor- | E mation on where to send the instrument for repair. HP-IB Description, Appendix À HP-iB is Hewlett-Packard's implementation of IEEE standard 488-1978 Standard Digital Interface for Program- mable instrumentation. Appendix A provides a general description of the HP-IB interface. This information is controller independent, but gives specific information about the 3478A as it relates to HP-IB. DEVICE A ABLE TO TALK, LISTEN AND CONTROL fe.q. CALCULATOR} Turning it On to be certain the instrument is set for the nominal line voltage in your area. | necessary, refer to the installation information in Chapter 4. As you press the line switch, Carefully watch the display as the 3478A goes through a complete internal self test and displays ¡ts HP-IB address. DISPLAY . RESULT The 3478A displays “SELF TEST" during the period of time it is perform. ing the tests. It wil] then display ‘SELF TEST OK” or an appropriate error message upon completion of the Self Test. | The message shown here affirms that the 3478A is ready for measurements. The factory preset HP-iB address for the 3478A is 237. This address may be ás easily changed to fit Your system needs by means of five Switches on the rear panel. The 3478A may also be set for q TALK-ONLY in Which case the display | Would indicate: HPIB ADRS.T.O. Note. © if the self test-does not pass, this |: message would be replaced by an error | message. | This entire process takes only a moment | to complete. At this point the 3478A is \ ready to. use and is set to the following | state: # Function: DC Volt Range: Autorange on Display: 5 1/2 Digits of Display Trigger: Internal Trigger Auto-zero: On NOTE Most 34784's Produced prior to January 1983 will not display “SELF TEST OK”, | | Test/Reset Even though the 3478A went through its Self Test during Turn-on, let's go through it manually. As we do, carefully watch the display, especially the 12 annunciators along the bottom. Every segment in the display (except for the top dot in the colon) is turned on for as long as you hold the Self Test button down. When the button is released, the display will remain for approximately 2 seconds while the Self Test is performed. The 3478A is then reset and returns to its turn-on state. A more complete description of the Self Test is found in Chapter ll. Should any of the five elements of the self test fail, a message wili be displayed identifying the general circuit area where the failure occurred. This can greatly reduce initial troubleshooting time. Do This | DISPLAY NOTE Most 3478A's produced prior to January 1983 will turn on every display segment for the duration of the Self Test (approximately 2 seconds) regardless of how long the Self Test button is depressed. | диет таит ше EY A EA = pu Rot Ee rm у Chapter [I Using The 3478A Introduction The -hp- Model 3478A Digital Multimeter is a very powerful bench instrument equally at home in the lab or production areas. In the first chapter you saw the . very basic features of the 3478A; in this chapter you will learn to use those features to solve your measurement needs. The detailed operating information in this chapter presents the most comprehensive instruction about ail of the multimeter's functions. Whether you use your 3478A as a stand alone bench in- strumeht or coupled with a computer for a measurement system, the information in this chapter will prove invaluable, Detailed Operating Instructions The goal of this chapter is to provide easy to find answers to the vast majority of questions you may have about using your 3478A. To this end, this chapter is divided into 12 major subject headings. Each subject presents the most comprehensive information about a particular feature or function of the 3478A. At the end of most subjects will be a short list of HP-[B remote programming commands that pertain to that subject. For more information on remote programming, refer to Chapter Ш. Operating Characteristics The Operating Characteristics of the 3478A are detailed in Table 2-1. This table is not the comprehensive table of specifications, but rather an abbreviated set. You will probably find that this table answers most of your questions about the capabilities of the multimeter without poring over several pages of specifications. Should you ever need to refer to them, the complete Table of Specifications for the 3478A is given in Chapter 4. Table 2-1. Operating Characteristics DC VOLTS. 7 AC VOLTS © BC AMPS 100 nanovolt resolution (30mv range) to 300V AC AMPS 1A resolution (300mA range} to 3A Full Scale Fuli Scale —- Maximum Shunt Resistance = ‚30 Zin: >101°Q, 30mV,300mV, and ЗУ range Maximum Burden at Full Scale = <900mV 10 MO + 1%, 30V and 300V range Bandwidth: 20Hz - 20kHz 14V resolution (300mV range) to 300V ful OHMS 1000 resolution {30 ohm range) to 30 scale True RMS Responding, Crest Factor = 4:1 at full scale Bandwidth: 20Hz to 100KHz {300KHz on 30V range) Zin: 1 MQ + 1%, in parallel with 76pF 1A resolution {300mA range} to ЗА full scale Maximum Shunt Resistance = .30 Maximum Burden at Full Scale = <800 mV megehms Full Scale Open Circuit Voltage: <6.3V Current through Ax: 300,300, 3KO range -imÁ 30KQ range - 100A 300KQ range - TORA - 3M} range - TuA 30MO range - 100 nA AUTOZERO What IS Autozero? The autozero key allows the user to selectively enable or disable the internal zero- ing technique used in the 3478A. Enabling autozero insures the user that any offset errors generated internal to the 3478A are continuously nulled with each reading. This renders the most accuracy. There are, however, many applications where disabling the autozero is advantageous. With autozero off, the internal reading rate nearly doubles. This would be im where speed is critical. Furthermore, the pletely static state with autozero off. This is useful when making measurements in extremely high impedance circuits where the internal switching transients of the 3478A may affect the reading accuracy. Of course, any range or function change that takes place with autozero off is automatically accompanied with an autozero update. The thermal stability of the measurement environment is the most important factor in deciding whether or not to turn autozero off. By simply keeping the temperature of the 3478A at a fixed value, you can turn autozero off without adverse effects. portant in programmable applications 3478A input circuitry remains in a com- How it Affects Measurements DC Voltage and Current Do This ———turn-the-3478A-off—then-on-again: press: auto Notice that the display is being up- CERO dated more frequently, indicating a A faster reading rate. Also notice that the AZ OFF annunciator is on in the display. The Autozero feature is now turned off. Pressing the key sequence again will turn Autozero back of. Autozero is used to correct for smail offsets (thermal, etc) in the DC input amplifier circuitry of the multimeter. With the Autozero feature enabled (Autozero is enabled at power turn-on} the 3478A takes two measurements per reading: a “zero” measurement and a measurement of the input veltage. The displayed reading is the algebraic difference between the two measurements. The 3478A makes the zero measurement by disconnecting the multimeter's input terminals, and then shorting the internal input circuitry to circuit common. It then switches back for an input voltage measurement. All switching is internal and is automatic, 8 0 ba y Ea AA Mia — ели лен pT a il lm EE = a AUTOZERO (Cont'd) With autozero turned off, whenever a new function or range is selected the 3478A immediately takes one final zero measurement and stores the results in its internal memory. Subsequent measurements of the input voltage subtract this one zero measurement to correct the reading. Since only the, input voltage is measured, the reading rate almost doubles. AC Voits and Current AC voltage and current measurements use different input circuitry than de voltage and current measurements. However, with autozero on, a zero measurement is made to null any errors in the A/D converter. Turning autozero off has the same effect as on dc voits and current. Resistance Measurements For 2-wire ohms measurements the autozero feature performs just as it does for DC voltage measurements. Resistance measurements using the 4-wire mode require different considerations. The zero measurement is normally made with the input amplifier shorted to circuit ground. In the 4-Wire ohms mode, the input amplifier is shorted to the 4-Wire SENSE LO terminal for the zero measurement. With autozero “ON”, the zero reading is updated for each measurement cycle. With autozero " OFF”, the reading "a ee , is-not updated and may cause an ohms measurement error if the resistance of the test leads change. To prevent this error, a new zero reading should be taken by changing or updating the state of the 3478A anytime test leads are changed. See Also: Display (Integration Time) and Optimizing Reading Rates Commands ZO Turns autozero off Z1 Turns autozero on EPR FCP TEL OL HH EOFS F A ir Legh “hii CALIBRATE — What is Electronic Calibration? One of the many features of the 3478A is electronic calibration. This represents a totally new concept in Hewlett-Packard voltmeters. Before, voitmeters had to be removed from their mounting, have their covers removed, and mechanical adjustments made. Then the voltmeter had to be reassembled and installed. But how, calibration may be done by pressing a front panel button and there is ab- solutely no disassembly required. It is beyond the scope of this section to present the entire calibration procedure. For complete calibration information refer to the 3478A Service Manual, -hp- part number 03478-90001. Briefly, Electronic Calibration is done by applying a known voltage {or resistance or current) to the voltmeter and telling it the exact value of that voitage. The voltmeter then takes ten readings and compares the average of those readings to the known value. A "CALIBRATION CONSTANT” is calculated to correct the reading to the known value and then stored in the voltmeter's memory, These Calibration Constants are generated for each range and function of the meter. All subsequent measurements are corrected by the constants. The Calibration Cons- tant memory is backed-up by a long life battery to maintain the constants when power is turned off. | Calibrate Enable ee -On-—the-front-panel—of—the -3478A a sa smal! “GTS Fy STi ten Tábelea CAL This Bee a am 11 00 switch, when rotated so that the slot is vertical, enables the calibration procedure of the 3478A. This switch should not be turned except when qualified service trained personnel are to perform the calibration procedures. Enabling the CAL switch may cause loss of calibration if proper procedures are not followed careful- iy. + Commands C Calibrate (see the 3478A Service Manual) 10 CURRENT Measuring Current Your 3478A has the capability of measuring DC or True RMS AC Currents up to 3 amps in two ranges. The current function is protected by a 3 Amp, 250V fuse. i the fuse opens, refer to Chapter IV before replacing. The illustration below shows the internal! current shunt and fuse used in the 3478A. The unknown current flowing through the current shunt produces a voltage which can then be measured. Current inputs of greater than 1 amp may cause the current shunt to change value slightly due to. self heating (somewhat like a thermistor). This may cause inac- curacies in the measurement. Sufficient time should be allowed for the circuitry to settie after the measurement is complete, hefore other critical current measurements are made. DC Current Press the DC Amps key and select the appropriate range {or let the 3478A autorange). When measuring currents, remove all other test leads from the 3478A front panel. There are two ranges available for current measurements: the 300 milliamp range and the 3 amp range. Up to 10 microamps of noise may be seen on the 300 mililamp range. AC Current [ra ВЕ Measuring ac current is identical to dc current, except that you use the AC Amps key to select the measurement function. The specified range of the AC ammeter is 30 milliamps to 3 amps. Lower accuracy readings down to 1 milliamp may be taken on the 300 milliamp range. Up to several hundred counts of residual offset may be seen on the 5% digit display with the input open. 1 SENSE INPUT la WIRE) 12 WIRE! Commands FE Selects DC Current mode (also Hb) F6 Selects AC Current mode (also HB) OZ AZ * sHUNT= 19 - MAY Co 3A 7 : ALL TERM E 5069 pk A —_ MAX = 3A/250V CIRCUIT x FUSE HERE > _ LS В : OC OR AC SOURCE y Figure 2-1. Current Measurements 11 DISPLAY How it is Used Another of the unique features of the 3478A is the 12 character alphanumeric display with 12 dedicated annunciators. The alphanumeric display may be used in one of three modes: NORMAL, MESSAGE, or USER GENERATED MESSAGE. The annunciators are used to indicate the current state of the multimeter's features (SRQ, autozero, 2- or 4- wire ohms, etc.). Do This press: This puts the 3478A in its SELF TEST mode. For now, just watch the display and notice the 12 characters in the display and the 12 annunciators. Normal In the NORMAL mode of operation the display is used to indicate the resuits of the measurement, whether dc voltage or ohms, etc. The measurement is displayed in the 2nd through 7th characters in the display. The first digit displays the polarity {+ or —) of the xeading. The measurement function (and, in some instances, an indication of range) is given in the last four characters of the display. The maximum display is 303099 with the decimal point appropriately placed for the range. Do This press. This puts the meter in the de volts | - y | | function, manual range mode. Note the ) LA M RNG annunciator in the display. press: Press these keys several times and watch the display as the decimal point 3 OR | moves across, and as the display indicates MVDC for milli-volts DC, and then VDC for Volts DC. The display is always read directly. Do the same in the 2-wire ohms mode. Watch as the display indicates OHM, KOHM (К! ohms) and MOHM (Meg-ohms}, 12 ea ar > DISPLAY (Cont'd) Abnormal Multimeter Readings If a reading is larger than a particular range can display, the display will indicate an OVLD with the measurement function and decimal point still displayed. If the A-D convertor is inoperative, the display will indicate “A-D TEST FAIL" or " AD LINK EAIL” . The 3478A will continue to try to make a reading, and if it suc- ceeds, it will display the reading. # Message it was demonstrated in the last two paragraphs that the 3478A is capable of displaying error messages. There are severa: otner messages the 3478A may display. For example: . Do This press: The display shouid now indicate = "ENABLE CAL”. This message indicates that the calibration switch must be set to the calibrate position before the instrument can be calibrated. The display now shows the HP-IB address of the 3478A. These are two more examples of messages which the 3478A may display. Other . possible messages will fall into one of three categories: Table 2-2. 3478A Messages ERROR MESSAGES (see Self Test) J.C. RAM FAIL The 3478A has failed ¡ts internal RAM self test. UC, ROM FAIL The 3478A has failed its ROM self test, indicating an error in the ROM. CAL RAM FAIL An attempt to write to the calibration RAM during calibration was unsuccessful. UNCALIBRATED | The CAL RAM has an incorrect checksum. The calibration of the 3478A is suspect, 13 DISPLAY (Cont'd) Table 2-2. 3478A Messages (Cont'd) A:D LINK FAIL The internal processor is unable to communicate with the A/D convertor. A:D SLOPE ERR The A/D convertor is not able to converge upon a result properly. A:D TEST FAIL The A/D convertor has failed its self test. CALIBRATION MESSAGE (see the 3478A Service Manual) CALIBRATING : The CAL key has been pressed and a calibration is in progress. CAL ABORTED Either an invalid key was pressed, an overicad was detected, or an A/D convertor error was detected. The calibration is aborted. CAL FINISHED A calibration cycle has been successfully completed, ENABLE CAL The CAL ENABLE switch must be turned 10 the CAL {vertical} position in order to do a calibration, - VALUE ERROR | The 3478A is unable to calibrate to the requested value. This message would result if; a. A zero calibration is attempted and the 3478A reads a raw value outside the range of + 50000 to - 40000 {assumes 5 1/2 digit mode) A gain calibration is attempted with a negative applied voltage, с. A gain calibration is attempted which is outside the range available, approximately a ms mi me mor aa AO, OF UL SCALE. oo ee ee eee ee ee a он но a mo de es cu An AC voltage calibration is attempted and the applied voltage is not 3VAC. À calibration is attempted via the bus with the "C” command, and a valid target number was not found in the display. ACH VALUE ERR | At the end of an AC voltage calibration when the 3478A attempted to compute the calibration constant for AC current, it computed a number outside of the allowed range. This could be caused by an invalid calibration constant on either the 300mV DC range or the 3A DC range. The ac voltage calibration is valid however. Y TF BL Tapeh Ber HPIB ADRSxx This is the HP-IB address of the 3478A, xx indicates the actual address of the the instrument (decimal) and may be altered by the address switches on the rear panel. OVLD This stands for overload and indicates that the input is too great for that particular range, 14 DISPLAY (Cont'd) User Generated Message Under computer control the 3478A can display your own user messages of up to 12 characters. Refer to Section lll, Remote Programming, for more information on this, D2text Places the message ”text” into the display D3text - Places “text” into display but the display is not updated. D1 Returns the 3478A to NORMAL display. Changing the Number of Digits Displayed When you are displaying measurement results (NORMAL mode), vou also have a choice of the number of digits displayed, i.e., resolution of the reading. This not only has a great effect on the reading rate but also affects the Normal Mode Re- jection (NMR). Do This press: This puts the 3478A into the 3 1/2 ee, - digit display mode. This mode has the o 5 fastest reading rate but the lowest resolution and little noise rejection. The integration time in this mode is .1 nower line cycle, “This is the 4 1/2 digit display mode. This mode provides 59 db NMR with an integration time of 1 power line cy- cie (16.66 mS at 60Hz, 20 mS at 50HZz). The 5 1/2 digit display mode provides 5 the best resolution and greatest amount of noise rejection. In this mode, 10 readings are taken, each with 1 power line cycle integration time, and averaged together. This provides 80 db of noise rejection. 15 DISPLAY (Cont'd) Integration Times As mentioned above, changing the number of display digits does more than merely change the resolution of the multimeter. It actually changes the "INTEGRATION TIME”, which determines the reading rate. This in turn will greatly affect the Nor- mal Mode Rejection (NMR) of the 3478A. The 3478A uses an integration type of A/D converter, Integration is a process where the effects of line related noise are averaged to zero over the period of an integral number of power line cycles (PLC's) during an A/D conversion. The integration time is not the same as the time for one measurement, The integration time is the time period, in PLC's, during which the input voltage is sampled by the voltmeter. At 4 1/2 digit display, the time required for one integration cycle is one PLC: 16.66 mS at 60Hz line frequency, 20 mS for 50Hz. The 3478A determines the line frequency by the setting of the 50/60Hz switch on the rear panel, in the 3 1/2 digit mode, the integration time is .1 PLC. Normal Mode Rejection {NMRiis the ability of a voltmeter to accurately measure dc voltages in the presence of ac voltages at power line frequencies. The 3478A has much better NMR at 4 1/2 digit display than it does at 3 1/2 digit display (59 db vs. Odb). The greatest amount of NMR is available from the 5 1/2 digit mode (80 db) where ten {10) readings are taken at 1 PLC integration time and averaged together. Commands N3 Selects 3% digit display —N4-—Setects 47 digit—display —— ~~ NE Selects 5% digit display 16 «ть ( > vv DISPLAY (Cont'd) Annunciators The 12 display annunciators, located along the bottom of the display, are used to indicate the state of the 3478A. Annunciator - .SRQ — LSTN TLK RMT MATH AZ OFF 29 40 S TRIG CAL SHIFT Table 2-3. Annunciators indication The SRQ annunciator indicates that the 3478A is trying to request service from the controller, Refer to Chapter (ll. » The LSTN {LISTEN} annunciator turns on when the 3478A is addressed to listen via the HP-IB. The TLK annunciator means that the 3478A has been addressed to talk via the HP-IB, RMT indicates that the 3478A is under bus control, that is, it is under remote operation. The front panel keyboard is inactive except for the LOCAL and SRQ keys {see LOCAL and LOCAL LOCKQUT in the next chapter}. MATH is not used on the 3478A, The Autozero feature of the 3478A is disabled. The 3478A is in the 2-wire ohms mode. The 2478A is in the 4-wire ohms mode. Thig-annunciator-indicates-that-the- 3478A. is-in-the manual. ranging. mode; auton .—.. fuen mix na came но но range is inactive. Single trigger means that the internal trigger is disabled. The voltmeter idles until either an external trigger pulse is received, the single trigger key is pressed again, or a TRIGGER message is received over the Bus. The CAL annunciator will blink if the 3478A requires calibration in the selected range and function, This annunciator indicates that the [SHIFT] key has been pressed, enabling the shifted functions. The annunciator will go off when elther the function is executed or the [SHIFT] key is pressed again, 17 OPTIMIZING READING RATES Why Optimize? There are several reasons why you would want to optimize the rate at which readings are taken by the 3478A. Perhaps you are using a scanner to measure a large number of points where a faster reading rate would mean a better picture of what is happening at a single point in time. Or maybe you need to read fast so that you don't waste valuable computer time waiting for a measurement result, Whatever your reason for optimizing reading rates, the 3478A can solve many of these application problems. Your maximum reading rate with the 3478A is in- fluenced by several factors. These include the signa! environment (line related and broadband noise, thermals, etc.), the desired accuracy, and convenience features such as autorange or autozero. The speed and timing of the A/D process is dependent upon a number of factors. The number of digits of resolution selected, whether or not the autozero feature is enabled, and the selected function determine how long it takes for the A/D to make a conversion. The reading speed is also affected by the value of the measured voltage (or current or resistance) and whether the display is turned on or off (HP-1B D3 command turns the dispiay off, see Chapter 3), : Your Signal Environment The signal that yBu are trying to measure is subject to line related and broadband noise which can interfere with your measurement. The 3478A works to reduce or reject this kind of noise by using a form of Analog to Digital (A/D) conversion call- _.. ed integration. Integration is a process where the effect of line related noise 15. averaged to zero over the period of an integral number of power line cycles (PLCs) during an A/D conversion. The measure of the ability of the multimeter to measure dc voltages in the presence of ac voltages (at power line frequencies) is called Normal Mode Rejection (NMR). The NMR of the 3478A is largely dependent upon the number of digits displayed. An important part of this process is to make certain that the 50/60 Hz line switch (S1 on the rear panel) is set properly: up for 50Hz line frequency and down for 80 Hz, * Integration Times Changing the number of digits of display does more than change the resolution of the reading. It actually changes the "INTEGRATION TIME” which determines the reading rate. The integration time is not the same as the time for one measurement, the integration time is the time period, in PLC's, during which the voltmeter samples the input voltage. At 4 1/2 digits of display, the time required for one integration period is one PLC: 16 2/3 mS at 60Hz line frequency or 20mS at 50Hz, 18 At 3 1/2 digits of display, the integration time is .1 PLC. Normal Mode Rejection (NMR) is a measure of the ability of the voltmeter to accurately measure dc voltages in the presence of ac voltages at power line frequencies. The 3478A has much better NMR at the 4 1/2 digits of display (60 db) than at 3 1/2 digits (Odb) because of the integration times. At 5 1/2 digits of display, the 3478A takes ten (10) readings from the 4 1/2 digit mode and averages them together. This provides the greatest amount of noise rejection (80db). Autozero The thermai stability of the measurement environment is also a very important consideration. By simply keeping the temperature of the 3478A at a fixed value, you can nearly double your reading rate by turning autozero off, without adverse effects. Although the 347 ВА is slightly less accurate, the faster reading rate may be worth it. In addition, any range or function change that takes place is automatically accompanied by an autozero update which removes any ac- cumulated offsets. If the measurement environment is quiet encugh to disregard NMR then only accuracy and resolution are the measurement speed factors and autozero may be turned off, Other Factors Influencing the Reading Rate 1. You can speed the reading rate by selecting a fixed range instead of aliowing the multimeter to autorange every reading. measurements can be made as fast as DC voltage measurements except on the 3Mohm and 30Mohm ranges where a settling time (30mS and 300mS respective- ly) is needed for stable measurements. The T5 Fast Trigger command (HP-18) is the same as the T3 command except that the delay is omitted. If more than one reading is required because of autoranging, etc, the delay will occur normally. 3 Consider the time it takes to transfer data over the HP-IB. For example, the TRANSFER command is much faster than the ENTER command on the -hp- 85 computer. 4. The maximum possible reading rate is with 3 1/2 digits displayed, autozero off, any DC voltage function, 60 Hz power selected, manual range, display turned off (see HP-IB command D3), a positive voltage measured, and internal trigger selected. | 19 В 2 AC voltage measurements- have-a built-in -600OmS.-settling-time. Resistance... …… ….… ; RANGING What About Ranging? The task of selecting the proper range on the 3478A may be done either automatically by the multimeter, or manually with the front panel keys. Reading the Display Do This Short the 3478A’s input terminals. press: Notice that the M RNG annunciator AUTO turns on in the display. This indicates MAN that the meter is in the manual! range mode. Pressing this key again returns the meter to the autorange mode. press: Press each of these keys several © times. Watch the decimal point as it | © on | moves across the dispiay. Also notice + the range annunciator in the display. For example, if the meter is in the DC Volts function, the display should in- the range selected. Try this in the other measurement modes. The display is always read directly and gives an indication of the range as a combination of decimal point and function display. Try connecting a variable de power supply to the multimeter, Make sure that the meter is in the DC volts function and autorange mode. As you adjust the power Supply, watch the display. THe display will momentarily go blank as the meter changes ranges. You might see a reading such as 47.215 MVDC. Reading the display directly, this would indicate a Measurement of 47,215 milli-volts de (.047215 volts). It should be apparent that the multimeter is in the 300 milli-volt range; the reading is too large to be read on the 30 milli-volt range. 20 ee a ma a Free ae as ma e mas ee ee dicate-V DC -or- VOC- depending В upon a en ee 0 RANGING (Cont'd) Table 2-4. Valid 3478A Ranges Function Ranges isply indication | H?-1B code | DC Volts 30mv, 300mY MVDC R-2,R-1 33V, 30V, 300V VDC RO,R1,R2 |, AC Voits 300mV MVAC R-1 3V,30V,300V VAC RO,R1,RZ DC Current 300mA MADC R-1 3A ADC RO N AC Current 300mA MAAC R-1 3A AAC RO Resistance 300, 3000 OHM R1,R2 3K9, 30K0,300K8 KOHM R3,R4,R5 IMO, 30MQ MOHM R6,R7 If the multimeter is in the manual range mode, the dispiay will indicate an OVLD when the input is greater than the particular range can handle. R— 2 selects the most sensitive range on any function. Autorange Autoranging on the 3478A is done by taking readings in the 4 1/2 digit mode on successive ranges until it finds the proper range that will allow for a display bet- d approximately. 9% of full scale (027000 In the autorange mode, the multimeter will up range (go to a higher range) if the display reading exceeds (+) 303099 counts or it will down range (go to the next lower range) if the display reading decreases below (+) 027000 counts. This assumes a 5 1/2 digit mode. These numerical autorange points are irrespective of decimal point placement. The difference between the two points is called the autorange hysteresis and is illustrated in Figure 2.2 for DC Volts. Autoranging in other functions is similar. | 21 RANGING (Cont'd) rok Am ан mm ek Ap Меж Ew Tw i t l ; 1 1 + I ; ; : 1 1 | 300V | | | yes | | 27y “T | ! | | Le E фт —нене т 30V | NS P30.1v | ; ! 1 ! | : y t & 1 1 1 i «р» RANGE SV | 270mV 7 3.0LV | ; i i ! ; E | = 1 y + ! 1 \ 300mV «popu 301mV: ! y : 1 se i 1 i ! 30m ; 30. 1m ı } 1 i ; E 1 > > > > > > Xx ow Er E го o Oo ca oO NY со =" г o в NY INPUT LEVEL # = DOWNRANSE POINT W = UPRANGE POINT 3478A- 2-0 Figure 2-2. Autorange Hysteresis 3 Manual Ranging aol O] 3 The 3478A is put in the manual range mode in one of three ways: pressing the AUTO/MAN {Autorange/Manual range) key, which will cause the meter to maintain its present range; the UP-ARROW key, which will cause the meter to go to the next higher range; or the DOWN-ARROW key to go to a lower range. In any case, when the 3478A is in the manual range mode, the M RNG annunciator is on in the display. Pressing the AUTO/MAN key restores autoranging. E The highest or lowest possible range depends on the function selected, For example, 30 mV is the lowest DC voltage range but 300mV is the lowest AC voltage range. If the 3478A were set to the 30mV DC range and you pressed the AC Volts key, the meter would default to the nearest valid range, ¡.e., 300mV. The meter will default to the nearest valid range when a function change is made. Command See Table 2-4, 22 REAR PANEL What is on the Rear Panel? Figure 2-3 illustrates the rear panel of the 3478A. The Rear Panel input terminals are selected by the F/R switch on the instrument front panel. There are two BNC connectors. One is for outputting a Voltmeter complete puise at the end of an A/D conversion. The second BNC connector is used to input an external trigger puise. See VOLTMETER COMPLETE and TRIGGER for more information on these connectors. And of course there is the HP-IB connector. The Rear Panel Switches Also on the rear panel of the 3478A is a set of 8 switches. See Figure 2-3. These switches are “on”, or in the ” 1” position when they are up. Switch number 1, farthest to the left, is the 5OHz/60Hz select switch. This switch should be in the up position if a power line with 50HZz frequency is being used, or down if a 60HZ power line is used. This switch changes the integration period (see OPTIMIZING READING RATES) of the A/D converter so as to obtain the greatest AC NMR and CMR rejection at the line frequency used. The reading rate is slightly slower when 50Hz is selected. This switch is read approximately once each minute and at power-on/reset. | Switch number 2 is not used, — Switch number-3-1s- used 10- select the. Power-on SRQ (PWR ON SRQ) feature. When this feature is enabled, i.e., the switch is up, the 3478A will generate an SRQ (Request Service HP-IB message) whenever the power is lost and then returned, such as a momentary power blackout, Switches 4 through 8 are used to select the HP-IB talk/listen address for the 2478A. The factory preset positions for these switches are, from left to right: up, down, up, up, up for a selected address of ” 23”. In order to select the talk-only mode, all five switches must be in the “on” or up position. For more information on the HP-IB address switches refer to Appendix A. 23 External Trigger Input Rear Pane! — HP-IB input Terminais Connector Voltmeter Complete Output Power Line Option Label Figure 2-3. 3478A Rear Panel and Switches 24 RESISTANCE MEASUREMENTS Measuring Resistance The 3478A is capable of measuring resistance from 30 milliiohm to 30 Megohms in seven ranges. Resistance measurements may be made in either 2- or 4- wire ohms configuration. The illustrations in Figure 2-4 show how resistance measurements are made. A known current is supplied by the 3478A and flows through the unknown. resistance. The DC voltmeter measures the attendant voltage drop. The 3478A is factory calibrated in the 4-wire ohms mode. If most or ali of your resistance measurements will be made in the 2-wire ohms mode, the 34/3A may be recalibrated in the 2-wire ohms mode. See the 3478A Service Manual. Resistances in excess of 30 Megohms may be measured using the extended ohms mode (remote operation only, see Chapter 3). How Resistances are Measured Resistances are measured by the 3478A sourcing a known current through the unknown resistance. A dc voltage measurement is made across the resistance. ВЕ The value of the resistance can then be determined (Ohm's Law, Resistance = Ne Voltage/Current). Figure 2-4 shows the current source and the voltmeter connections for both 2- and 4- wire ohms measurements. Table 2-5 shows the nominal current through the unknown resistance for the individual ohms ranges. Variations in currents are compensated for by the calibration constants. В Table 25. Nominal Currents through Unknown Resistanc Current Through | Maximum Open Range Unknown Circuit Voltage 300 TMA 6.3 V 3009 imA 5,3 V КО 1 А 6.3 V 30KQ i GOUA 5.8 Y 300K1 ТОНА 5.8 V 3MQ 1uA 5.8 V 30MO 100nA 5.8 V There are two situations in which the 3478A may indicate a negative (minus) resistance: either small negative voltages may exist on the circuit under test, or the inputs to the 4-WIRE SENSE and the INPUT leads are inverted from each other In the 4-wire ohms function. | in the 5% digit mode, the 3478A may show 10 counts or more of noise on the J 30 ohm and 30 Megohm ranges. If the 3% digit mode is used on the 30 Megohm range, special grounding and shielding may be required (due to the absence of AC normal mode rejection. 25 RESISTANCE MEASUREMENTS (Cont'd) 2-Wire Ohms The two wire ohms mode is used most commonly when the resistance of the test leads is not critical. Inaccurate results may occur when using the 2-wire ohms mode if the resistance of the test leads is very high, i.e., long test leads. Suppose you are making temperature measurements with a type 44004 thermistor. Refer to Figure 2-4, At 20°C, 40 feet of #24 A. W.C. copper wire has a resistance of 1.02 ohms. Two such wires would have a total resistance of 2.04 ohms. With a type 44004 thermistor this would result in an error of ‚1%. Command F3 Selects 2-wire ohms mode (also +3) 4-Wire Ohms The use of 4-wire ohms measurements alleviates the errors caused by the effects of test lead resistance. Figure 2-4 illustrates this point. The current through the thermistor is the same regardless of the lead resistance, and the voltmeter measures only the voltage across the thermistor, not across the combined lead resistance. The 4æwire resistance measurements are essential when highest accuracy is required, or where long lead lengths are present. F4 Selects 4-wire ohms mode (also Há) Extended Ohms The extended ohms feature of the 3478A is available only via the F7#remote programming command. With extended ohms, the 3478A can be used to measure resistances in excess of 30 Mohms. When in the extended ohms mode, the 3478A goes to the 30 Mohm range, 2-wire mode. An internal resistance of approximately 10 Mohms is placed in parallel with the input terminals. If this resistance is measured first and then your unknown resistor connected to the input terminals; the parallel combination can be measured and a calculation performed to determine the approximate value of the unknown resistance. The formula for the calculation is: | Ri * Rt > = AR 26 RESISTANCE MEASUREMENTS (Cont'd) Rx is the unknown resistance, Ri is the measured value of the internal 10 Mohm resistor and Rt is the measured value of the parallel combination. The test leads used should be very short, preferably a shielded twisted pair, to minimize noise pick up. } A program to make the necessary measurements, perform the calculations, and display the value of the unknown resistor is given in Chapter il}. "SYSTEMS #a : -- + Command F7 Selects the Extended Ohms function (also H7) (2- wire mode) LEAD RESISTANCE Fr 1.02 MN SENSE INPUT o ta WIRE] t7 WIRE} HI MN 28140 (ТУРЕ 4404 THERMISTOR LO AT 20°C} ЗА “hr, MAX ALL TERM | 1.02 |-- -*500vui— A==4 — — | mv memes mm vo ee a ta MAX MEASURED RESISTANC du IS 2816.040 AN ERROR = 3A/250V QF .07%. FUSE a „й *internal to the 34784 2-WIRE OHMS MEASUREMENT N SENSE (4 WIRE] ALL TERM MAX INPUT ‘2 „ео ВООМрК Ди 3A/250V FUSE LEAD RÉSISTANCE „й 4-WIRE OHMS MEASUREMENT Figure 2-4. Resistance Measurements 27 ep EE RESISTANCE MEASUREMENTS (Cont'd) Other Considerations 1. Always use the shortest possible test leads, especially at the higher resistance ranges. Ideally, the test leads should be a shielded, twisted pair to reduce noise pick-up, | 2. For best results, especially at 3 1/2 digits display, the input LO termina! should be connected to the 3478A chassis {earth ground). | 3. Additional settling time may be required when using the higher ohms ranges under program control. This is important if there is more than 200pF shunt capacitance connected externally as might be the case if you were using the 3478A with a scanner. Theoretically, the settling time necessary is: — RC+In(P/100) Where R is the resistance being measured, C is equal to 620pF plus any external Capacitance, and P is the desired percentage of step accuracy. For example, lets ; say we want to measure a 3.0 Mohm resistor through a scanner with 1200pF 0, ы capacitance (High-to-Lo terminals). If a short was previously applied (short to 3.0 ” Mohms = step), and a .001% reading is desired, the settling time necessary is: Since on the 3 Mohm range there is an internal delay of 30ms, an additional! delay of 30 to 35 mS should be allowed. The 30 Mohm range has an internal delay of 300 mS. 28 TEST/RESET What it Does The 3478A self test performs several checks on the digital and A/D converter circuitry of the instrument, À failure in any of these four areas is indicated by an error message in the display. When the self test is complete, the 3478A resets to its turn-on state. | Do This RS wh TEST/ *:. press: LES ET 4 | so. | TRIG This initiates the functional tests of the digital circuitry in the 3478A. The SELF TEST starts by turning every segment in the display on {except the top dot on the colon). These segments will remain on for as long as the Self Test button is held down. When the button is released, the display will remain for approximately 2 seconds as the self test is performed. It wilf then disp:ay “SELF TEST OK” or an appropriate error message. If the self test passed the HP-IB address will be displayed and the 3478A returns to its power-on state. If an error was detected, and the error message displayed, the HP-IB address will not be displayed but the 3478A will attempt to operate normally. Table 2-6. Self Test Error Messages J.C. RAM FAIL - failed its self test, U.C. ROM FAIL - ROM. UNCALIBRATED AD TEST FAIL A:D LINK FAIL - This indicates that the micro-computer's internal RAM (not CAL RAM) has The 3478A internal ROM has failed its self test. This indicates an error in the The random access memory that contains the calibration constants has an in- Mr Bp Mr? E a AA correct checksum. The calibration of the 3478A is suspect. The A/D converter has failed its self test, The microcomputer is unable to communicate with the A/D converter. Eor all failures refer to the 3478A Service Manual, DESIGNER FOR, SYSTEMS Use the HP-IB CLEAR command. (See Chapter lil) Command 29 TRIGGER MODES What is Triggering? Triggering is simply the process that Causes the 3478A to take a reading. There are three basic triggering modes available on the 3478A. These three modes are described after we look at the trigger indicator, Trigger Indicator The decimal point that is farthest right in the display will blink every time a reading is completed. H a colon or comma is piaced there by a remote operation (D2 command, see Chapter III), the dispiay will alternate between a comma and a colon. INT Internal Trigger In the internal trigger mode the 3478A triggers itself to take readings at the maximum possible rate. This mode is automatically selected at instrument turn-on and after performing Self Test. A settling delay has been added before each A/D conversion in the ac volts and Current and the two highest ohms ranges to ensure ac- Curate readings. .. | ¿DESIGNED FOR SYSTEMS Comma nd Single Trigger The single trigger mode allows you to manually trigger the voltmeter from its front panel. The first time you press the Single Trigger key the 3478 will take one reading, display the results, and go to the single trigger mode. Subsequently, each time the key is pressed the multimeter will make one reading, display the result, and then sit idle, waiting for another trigger. areas where the probe must not slip. What you do is this: press the Single Trigger key and position your finger to press the key again. You can then place the probe, press the Single Trigger key, and then remove the probe, all without taking your eyes off of the probe. With the probe safely removed, the measurement is still held on the display. 30 _ TRIGGER MODES (Cont'g) When the 3478A is in the Single Trigger mode 7'd you attempt to ch 44 or change function, the left hand portion of the display wij change ranges : > . go blan ception of the decimal point) until another t99er impuise js rece, < (with the ex- / ved. J TZ Selects the Single Trigger Mode External Trigger The external trigger mode is enabled by the * Trigger ke the single trigger mode except that the trigge "Pulse is applied + nector on the rear panel of the 3478A. Tt®rnal Trig... nour BNC con. compatible or may be actuated by a simp!CA Closure. «The 247, TTL logic gered on the negative edge of the TTL pulse? Must be 4 minim 78A is trig- duration. If a trigger pulse is received whil¢'"g Is in Progress mu of 100ns ignored. "€ Imp Y and is identical to uise is Command TZ Selects the External trigger Associated HP-IB Commands T4 Selects the Trigger Hold | it . T5 Fast Trigger. Same as T:. the Settlin 9 dela ni Y 'so AC Volts and current, a'9Pest ohms ranges mitted on po . ay af, E a Ps dz From any trigger mod. SO Le "tiated $ the HP-IB GET comme 22" IS disableg by the T1, T3, T4, or T5 c VOLTAGE MEASUREMENTS Measuring Voltages Whether you use your 3478A on the bench or as part of a sophisticated test system, probably most of your measurements will be voltage measurements. If you have special requirements in taking voltage measurements, be sure to read the sections on Optimizing Reading Rates, Display, Autozero, and Triggering modes. A complete Table of Specifications is given in Chapter 4 of this manual. DC Voltage Measurements DC voltages measured on the 3478A are both simple and straightforward. Press the DC Voltage key and either select the appropriate range or allow the multimeter to autorange. Read the display directly {no multiplying the reading by the range, etc.) for the measured voltage. Up to 1 microvolt of noise may be seen on the 30 millivoit range, Command F1 Selects the DC Volts mode (also H1) AC Voltage Measurements Like DC voltage measurements, AC measurements are very straightforward. Press _ the AC Voltage key and appropriate range key(s). The display is read directly for. _ the measured voltage. The 3478A uses a True RMS to DE converter for AC voitage and current measurements. Unlike multimeters that use an average detector, the True RMS converter allows accurate measurement of voltages that are often noisy, non- periodic or non-sinusoid. The RMS converter will accurat tely measure the True RMS value of sawtooth or triangle waveforms; squarewaves; or low repetition rate, high crest factor (ratio of peak to RMS} pulse trains. 32 VOLTAGE MEASUREMENTS (Cont'd) RMS measurements are made hy calculating the instantaneous square of the input signal, averaging № and taking the square root of the result. This provides a DC voltage that 15 proportional to the RMS value of the waveform. A DC voltage measurement is then made by the A/D converter. | it should be noted that the AC voltmeter accuracy is specified only for inputs greater than 10% of full scale. Hence the specified range is 20 millivolts to 300 volts. The 2300 millivolt range Is useful for lower accuracy readings down to miilivolt. Up to several hundred counts of residual offset may be seen on the 5% digit display with the input shorted., | Command £2 Selects the AC Volts mode (aiso H2) Г. SENSE INPUT (4 WIRE] 12 WIRE! Ox © [oc OR АС 300VA VOLTAGE | MAX SOURCE A A TERM eed = А a + 500VPk A cae aha UA ete mew aan am ae e we pe mm en MAX 1 = - 3A/250V | FUSE Aves od 3478-245 Figure 2-5. Voltage Measurements 33 IL eL A Le SP en EE ee Ee еее пенемменант тео VOLTMETER COMPLETE What is Voltmeter Complete? ‘The Voltmeter Complete BNC connector on the rear panel of the 3478A provides a pulse at the completion of every A/D cycle. This pulse is used to indicate that the 3478A is ready to output an answer or be retriggered, The pulse is a negative going TTL compatible pulse of about 145 duration, : Using the Voltmeter Complete Pulse The following illustration shows one way to use the the Voltmeter Complete and External increment feature of the 3478A in conjunction with the -hp- Model 3497A Data Acquisition Control Unit. Once the connections are made, the 3497A advances to the next channel with each Voltmeter Complete pulse. # — Figure 2.6. Using Voltmeter Com >= 34 Chapter II! Remote Programming Introduction in this chapter you will learn about remote programming your 3478A over the Hewlett-Packard Interface Bus (HP-18) using a computer / controller. If you are not familiar with HP-1B or some of the terms used in this chapter, Appendix A contains a concise description of HP-1B. Be sure that you have read through or at least familiarized yourself with Chapter 2 of this manual before starting this chapter. You will need to understand the operating characteristics of the 3478A before you begin programming it. Scope The descriptions presented in this chapter are in general terms to optimize the flow of information regardless of the type of controller you are using. This means that both the inexperienced user as well as the experienced programmer will be programming the 3478A efficiently and productively with minimum instruction time. There are, however many example programs given to enhance the discussion, most of which are given in an enhanced BASIC (Beginners All-purpose Sym- bolic Instruction Code) programming language such as the Hewlett-Packard Model -hp- 85 uses. Trying Out a Command Before we actually begin the programming discussion, let's look at a simple example that displays your name on the 3478A display If you have one of the con trollers shown below, type in the commands as shown. Even if you don't have one of the controllers listed, read through this section anyway as it provides a basis for later discussions. Enter the command exactly as shown using your own name capital letters - in place of ” your name”. | Computer Type The Message: Press: -hp- 9825 wrt 723,” D2your name” [EXECUTE] -hp- 9835, 9845, 85 OUTPUT 723; D2your name” [EXECUTE] (on the -hp- 85, PRESS [END LINE] 35 Actually, any message of up to 12 characters may be displayed in this manner, The command "D2your name” tells the 3478A to display the message ” your name” in its display; “ D2” is called the ” COMMAND CODE”. The 3478A cannot display lowercase letters, it displays unusual symbols instead. It can display, however, special characters such as $, %, &, #, etc. Try these characters in place of “your name”, At the end of this chapter are several blue pages that describes each of the program commands the 3478A will respond to, and how they are used. As an added plus, at the back of the manual is a Command Quick Reference Guide that you can tear out and keep with your 3478A. Addressing ; Do This The 3478A will display its HP-IB ag- dress in the form: HPIB ADRS XX. XX represents the actual address which is factory preset to 23, Each instrument that YOU connect to the interface bus has a unique “address”, and the 3478A is no different. The address provides a way for the controller to send or receive data from one instrument on the bus when actually there are several instruments connected together. In the previous example, where you displayed your name, we used the statement "OUTPUT 723”. The "723" refers | ; to- the controller “interface ‘select code (isc) Which is 7 and the 3478A factory preset address which is 23. If you need to change the address of the 3478A refer to the installation information in Chapter 4. All the examples in this chapter assume that the 3478A will be addressed at 723 {which is also called the device select code, dsc). When the controller tells a particular instrument to talk, i.e., send data over the In- terface Bus, we say that the instrument has been ” Addressed to Talk” Likewise, when the controller tells an instrument to listen, i.e., receive data or instructions from the Bus, the instrument is said to have been “ Addressed to Listen”. The 3478A is capable of both talking and listening or it may be set to Talk-only, in which case it cannot listen to instructions or data coming over the Bus. There can be only one instrument addressed to talk on the Bus at any one time, 36 Sending Instructions to the 3478A The Instruction Message is one specific form of an НРАВ Data message (see Ap- pendix A). it is used to cause the 3478A 10 change states, i.e. make an ac measurement instead of a de measurement, or perform a particular operation such as output status information, etc. Look at the blue pages at the end of this chapter. They describe each of the instruction Messages the 3478A will respond to and how they are used. An abbreviated table is given in the Command Quick Reference Guide. Look at Figure 3.1, The instruction message may contain from one to three parts as shown: the Operation Mnemonic; Qualifier, and Data. The Operation Mnemonic is a single. letter "which is always used. The Qualifier and Data portion of the message are used as defined by the operation to be performed. An example of a command which requires only the operation mnemonic is the 7S” command. À function or range command requires the mnemonic plus a qualifier, e.g., F2" or R-1. The "D2" or "D3" commands require the mnemonic 7D”, a qualifier (either 2 or 3), and data, which is the text to be displayed. The diagram also shows that instructions may be linked together forming a string of instructions. J Operation Output Mnemonic ¡Command ; Note 1 Mate 1. The computer or controller output command as shown in the figure includes the HP-iB address of the instrument to which the Instruction Message is being directed, l.e., 723. It also includes any delimiters required by the computer language syntax. A deiimiter is a character that is used either to separate one ex- pression from another, or to terminate a list. Delimiters include semicalons, quota- tion marks, commas, spaces, etc. When linking instructions it is not necessary to add delimiters between instructions. Note 2. Some computers and controllers generate a Carriage Return/Line Feed (CR/LF) automatically as part of the output command. Check the output command syntax for your specific computer. The CR/LF is a delimiter that terminates a fist. The 3478A ignores the CR/LF except in the DZ or D3 commands. Figure 3-1. Sending Instructions 37 Sm hm et TES SL WEE mmm pe e rn Et eT TE Tes et pm TT . 3 = e A IE y eo. _- - . HE В sn : В а pm IIT Ae Side rar a =r A me т al oe Hi ir e . ... r. SEPA apn Tory ots o ET EE SER o E eT TRE TRINO e ESTI ore mbr A o is Frais Ts ns TE CEE = AE EIR FE TE TA FE и = En TE ly il Eco TET A Procedure Decide what YOU want the instrument to do and determine the appropriate Opera- tion Mnemonicis). For example, the Operation Mnemonic for function codes is F, the Mnemonic for range codes is R, etc. Specify the Qualifier and Data as necessary. Let's look at an example and break down the instruction message. To set the 3478A to the DC Volts function and 30 volt range, the following message would be sent: interface 3478A select code address 2 instruction Messages | linked together OUTPUT 723.” F1 RI" ii E Й Sets range to 30 voit range — sets function to DC volts (Fis mnemonic and 1 is qualifier}, computer output command syntax depends on the computer being used. See Note 1 above. Figure 3-2. Instruction Example string. In the NEXT section we will look at the HOME commands of the 3478A. Each HOME command is actually made up of several instructions, But for now, let's take another look at using multiple instructions... Wr Sample Problem We want to make an ac voltage measurement that we know to be between .20 volts and 1 volt. We also want Autozero on and the measurement to be made in # First, it is an ac voltage measurement, therefore instruction “F2” (Function 2) IS used. We don't know exactly what fange to use, so let's use the autorange feature, “RA” (Range Auto). The instruction for autozero on is “71” Zero 1), and for the 4 1/2 digit mode, ” Ng” (Number of digits 4). Our command string now looks like: “FZRAZ1N4" 38 ne à Since we know the voltage to be measured is small, let's set the 3478A to a low range before we autorange. The instruction "R—2” (Range —2) will do this for us. Furthermore, if we want the meter to only take one reading we could add the instruction ” T3” (Trigger mode 3) to the end of the string. By adding it at the end, the meter is set up for the measurement before the reading is actually triggered. The complete string, along with the QUTPUT statement is: OUTPUT 723; "F2R-2RAZ1N4T3” | Instructions are implemented as they are received over the Bus. In other words, the 3478A will go to the ac volts mode before it goes to the lowest range. it will go to the lowest range before autorange, it will autorange before turning autozero on, etc. The last thing it will do is trigger for the measurement. A very importanf matter to keep in mind is to use the proper computer syntax. Remember that the examples given in this chapter were written for a computer such as the -hp- 85F. Check your computer 1/0 manual for the correct syntax and “in the examples given, use that syntax. Home Commands There is a series of eight preset commands conveniently provided in the 34784 which greatly ease programming. These commands, called HOME commands, set the 3478A to predetermined states as defined in Table 3-1. In the sample program given earlier, we ended with a string of six commands which could actually be replaced with one HOME command, "HZ2”, | Table 3-1. Home Commands Lets Caridad md amm mmm 22 0 0 2 0 мк ae 0e 0 0 LL Description daa nn ee ae ae nm RE ee HO HOME Command. The 3478A is placed into the DC voits function {F1}, autorange (RA), trigger hold (T4), 4 1/2 digit display (Ná), and autozero on (Z1). Any result ready to be output to the bus or display is erased, External trigger input is disabled. This command is equal to: "F1T4R-— 2RAZ1N4”. The meter will wait for a trigger command such as T3 or TS. = Measure DC Volts. This function is the same as the HO command except that a single trigger occurs, and if the 3478A is addressed to talk will output the reading. This command is equivalent to: " F1R- 2RAZiNAT3" HZ Measure AC Volts. This command is the same as H1 except that an AC Voltage measurement is taken. Equivalent to: “F2R-2RAZ1N4T3” НЗ Measure 2-Wire Ohms, identical to H1 except takes a 2-wire ohms measurement. нА Measure 4-Wire Ohms, ldentical to M1 except takes a 4-wire ohms measurement. M5 Measure DC Current. identical to Mi except takes a DC Current measurement, HE Measure AC Current. identical to H1 except takes an AC Current measurement. H7 Measure Extended Ohms. identical to H1 except take an extended chms measurement. ‘39 LT I PIR UE о E Ди perm Timi AIN Ta To a AA AEE rises Soiree ds LEE + EEE AO 7 EC IL SE EE TT Es TEA Te a AA Tn ges Tata art Thee mr at em Fla a a rad LO fue = у Using the Home Commands You can use the HOME commands just as they are or combined with other commands. For example: OUTPUT 723; "H1” would set the 3478A to the DC Volts function and take one reading. If you want the 3478A to be in the internal trigger mode you could send: OUTPUT 723; ”H1T1” in order for ”T1” to be in effect, it must follow the "H1" command, otherwise the “H1” command will put ” T3” in effect. Programming Hints When more than one command is sent to the 3478A in one ” QUTPUT” instruction statement, the commands are executed as they arrive. Therefore it is best to make the trigger statement the last Statement in the command string so that the 3478A will be set up for the measurement before it triggers. If you send the command ” T3T1”, the “ T1” command is the last one received and will be in effect, Instructions are sent to the 3478A as a series of 7-bit ASCII characters (parity bit is ignored}. All lowercase letters, spaces, commas, and semicolons are ignored and may be freely used to format commands for easy readability. All null characters, carriage return, line feed, form feed, and vertical and horizontal tab characters are also ignored. AIF other characters and sequences not explicitly allowed (see the Command Table) will result in an error. Errors will be discussed later. For example, sending the message: Po OUTPUT 723;” Function 1 Range 1” would be the same as: OUTPUT 723:"F1R1” When a multicharacter command is received, if a character is received which does not fit into the syntax of the command, the command will be aborted and an error will be generated. An attempt is made to process the character as if jt were the first character of another command. For example, the command ” FR3” will cause a syntax error but then go on to range 3 (that is, ”R3”), See Require Service, Status Register. | Commands which accept binary arguments (represented by x in the command table) and the D2 and D3 commands are exceptions to the above rules. Any of the 256 possible 8-bit bytes may be sent as a binary argument, any ASCH character greater than 31 (decimal) may be sent as part of a text message (see Appendix B). Note, however, that lowercase alpha characters are not represented as alpha characters in the display. | 40 Receiving Data from the 3478A The 3478A has the ability to talk to the computer or other instruments, giving the results of measurements or status information. This is another specific form of the HP-IB Data Message. The controller must tell or ” address” the 3478A to talk in order for it to send data. Example. From the last section we saw how to make the voltmeter go to the DC Volts function and 30V range. Now we will see how to read back the measured voltage. | 10 OUTPUT 723; F1R1” (from the last section) 120 ENTER 723; AS -30 DISP AS 40 END The 3478A is addressed to talk by the ENTER 723 command in the second line. The measurement result is stored in the string variable A$ and displayed on the controller's display. Remember that the actual computer syntax used (i.e., ENTER, OUTPUT, DISPLAY, etc.) is dependent on the computer that you are using and may be different than the examples given. You should refer to your computer's 1/0 programming manual. Let's try another very simple example. You can use your controller to determine the setting of the 3478A's Front /Rear switch. This is done by sending the program command ” $” and then reading the output. o This [TDT TTT TL Enter the following program and run it. 10 OUTPUT 723; "8" 20 ENTER 723; S1 30 DISP 51 40 END the value read back from the 3478A (variable S1 in the example shown) is ” 0” the rear panel terminals are selected, If the value is ” 1” the front panel terminals are selected. Try this program with the switch in both positions. If the 3478A is in the single trigger mode (S TRIG annunciator on) this program will not work. Either press [LOCAL] ИМТ TRIG] keys or reset the voltmeter. 41 Output Format Messages are sent by the 3478A as 13 bytes in the following formats: Voltmeter Reading: +d.dddddE+d CR LE Overload: +9.99999E+9 CR LE The character ” d” represents a single digit. If the 3478A is in the 4 1/2 digit mode, the last digit returned before the ”E” will be a 70”, In the 3 1/2 digit mode the last 2. digits will be "0" 's. 3478A Bus Capabilities So far we have seen how to program the 3478A for specific operations and how to read back the data. But now it is time to move on and look at special HP-IB commands and advanced programming topics. Talk Only Mode y Many applications of the 3478A, a simple data logger for example, may require that the instrument take readings and output them to some device such as a _ “Printer. AI this is to be done without the aid of a controlier. The 3478A’s TALK ONLY mode allows just that type of transaction to occur, The 3478A is set to the talk only mode by setting the 5 HP-1B address switches, on the 3478A rear panel, to the ” 1” (up) position. Refer to Chapter 4. Measure- ment data is output after each completed reading. Function and range settings, etc., are done from the front pane! keyboard. | 3478A Response to Bus Messages The following topics, arranged in alphabetical order, deal with HP-1B commands (see Appendix A) and the way the 3478A responds to them. Refer to the 1/0 programming manual of your controller for specific information on syntax and actions taken by the HP-1B interface when sending the message. The examples given apply to the -hp- 85, 9835, 9845 computers, except where noted, 42 E CLEAR Examples Comments Upon receiving the CLEAR message, the 3478A will be placed into its test/reset routine. The routine starts with the 3478A performing its internal self test and reading its rear panel HP-IB address switches. Any errors in the self test will be noted in the voltmeter display and will cause the hardware error bit to be “set” in the status register and the appropriate bits to be set in the error register. If there are no errors, the HP-IB address will be displayed for approximately 2 seconds, The power-on state for the 2478A is: DC Volts function, Autorange, Internal Trig- ger, Autozero On, and 5 1/2 digit mode. 43 LOCAL Examples LOCAL 7 LOCAL 723 Comments The LOCAL 723 message clears the 3478A from the REMOTE operation mode and reenables front panel control. Pressing the front panel LOCAL key ac- complishes the same thing, provided the key has not been disabled by the LOCAL LOCKOUT Message. LOCAL 7 removes every instrument on interface 7 from the remote mode. | | the 3478A is in Remote with Local Lockout set, the only way to return to front panel control is to either turn power off and then on again or execute the Clear Lockout / Set Local (CL/SL) message. For many controllers this is the same as the LOCAL command, i.e., LOCAL 7. The command LOCAL 7 takes all instruments out of Local Lockout that are on that bus. The command LOCAL 723 would return the 3478A to front panel control but a subsequent REMOTE command {or OUT- PUT 723) would return it to LOCAL LOCKOUT. ¥ LOCAL LOCKOUT Example Comments # The LOCAL LOCKOUT message locks out the 3478A's front panel keys, including the LOCAL and SRQ keys. The lockout will remain in effect until it is cleared over the interface bus by sending the LOCAL message to the multimeter or cycling the 3478A's power. 44 437 о | REMOTE Exampies ‘ - В “REMOTE 7 Comments The REMOTE command is used to enable the 3478A to switch from local front panel control to remote program control. The 3478A must actually be addressed before it :will go into its Remote state. The Remote state for the 3478A means that the front panel keyboard (except the LOCAL and SRQ keys) is disabled. The REM annunciator in the display is turned on. The 3478A remains in the same state after ¡t receives the REMOTE command that it was in before receiving it. To disable the LOCAL and SRQ keys use the LOCAL LOCKOUT command. ; You will seldom find it necessary to execute the REMOTE command. The REMOTE “message is independent of other HP-IB activity and is sent on a single Interface Bus line called REN (see Appendix A). Some controllers set the REN line true at power-on, or when reset, which has the same effect as sending the Remote message with only the interface select code, ie, REMOTE 7. Before any instrument will actually go into the Remote state it must be addressed, Therefore, when --the 3478A is. first addressed, such as OUTPUT 723, tt will actually go to the remote state. | aa aaa e a a 45 a AT pi "en Ets ufr ft mm = ve нае IT EEE н.в REQUIRE SERVICE (SRQ) Another important feature of the 3478A is that you can program it to interrupt the controller when certain conditions are met. Of course, the controller must also be programmed to respond to the interrupt. The Require Service (SRQ) message is used to implement this and is independent of all other HP-IB activity, SRQ is sent on a single Interface Bus line called the SRQ line (see Appendix A). The 3478A MUST BE PROGRAMMED for the interrupt before the interrupt will take place. The following list gives the possible causes of interrupt that the 3478A can be programmed for. 1. Power-on/ Reset. The 3478A will interrupt the controller when the 3478A power is turned on, it received a Device CLEAR or Selected Device CLEAR, or the 3478A was reset, 2. CAL Failure. The 3478A will interrupt the controller if an attempted calibration failed. 3. Front Panel Keyboard. You can use the front panel SRQ key on the 3478A to interrupt the controller, | 4, Hardware Error. if a hardware error occurs, the controller would be interrupted. 5. Syntax ErroR If the controller sent an invalid instruction, the 3478A would interupt the controller. — 6. Data Ready. The 3478A would interrupt the controller after each completed measurement, How to use SRQ When the Require Service message (SRO) is sent, the computer must determine first which instrument is requesting service, This is done by conductfhg à SERIAL POLL (SPOLL) of every device on the bus which is capable of requesting service, When an instrument is polled, it responds by sending a ” STATUS BYTE” which indicates whether it requested service, and if so, the nature of the request. If the Status Byte for the instrument polled indicates that it was not requesting service, the computer would continue to poil the other instruments on the bus until the proper one is located. This, of course assumes that the controller has been programmed to respond to the SRO interrupt, 46 — Status Register and Status Byte The status register is used to monitor the six possible interrupt conditions. it is possible for one or more bits of the status register 10 be true without the 3478A causing an interrupt. The interrupt will only occur when the SRQ mask has been set for particular conditions. Refer to Figure 3-3. If the SRQ mask is set for certain conditions and one OT more of those conditions occur, bit 6 of the status register will go true (true being a 17), the SRQ annunciator in the display will turn on, and the HP-1B SRO message will be sent. The controller must be programmed to respond to the SRQ message. The Status Byte is an 8-bit byte that may be used to determine the current status of the 3478A regardiess of whether an interrupt (SRQ) has occurred. The Status Byte comes from the status register and is output in response to à serial poll which is described in the next section. | Bit 7 Bit 3 Bit 2 Bit 1 power-on Hardware Syntax N/A Reset | Error Error | (always О) SRQ Figure 3-3. Status Register Setting the SRQ Mask The SRQ mask can only be set 10 mask bits 0-5 on the Status Register. Default mask value is OO. To set the mask first determine which conditions you want to interrupt the controller, e.g., data ready, calibration procedure failed, syntax error, etc. Determine the two digit octal code for those conditions. Then output the ~~ ~~ ~~ "M" instruction mnemonic. followed by the octal code as the qualifier, that is: Mixx", where XX is the octal code. Think of the SRO mask as a mask that sits over the lower six bits of the status register and masks out those conditions you don't want to cause an interrupt. Figure 3.4 shows the status register and the SRQ mask set for bit O, Data Ready. {3 o SRG _ о o ó = 01 toctal Mask | For Dats Heady SAG Bit 2 Syntax Error [Always 4 Hardware Error Service Request Status Register Figure 3-4. Status Byte and SRO Mask 47 Example 1. Data Ready SRQ Data Ready is a feature of the 3478A that allows it to interrupt the controller after each completed measurement (data ready). This means that the controller doesn't waste valuable computing time waiting for measurement data but pro- ceeds with its work until interrupted. To enable the data ready feature on the 3478A, bit O on the SRQ mask must be set. Remember that bit O will be true in the status register anytime data is ready but for the SRQ to occur the mask must be set. The bit pattern for the mask would look like: bit $. 5 4 3 2 1 0 value: 0 O O O O 1 О 1 01 is the octal representation (see also Figure 3-4) Consequently, we would use the command: OUTPUT 723; MO1” to set the mask for Data Ready. Therefore, whenever the 3478A has data ready it will interrupt the controller via the SRQ line. The controller will only be interrupted if bit O is true, meaning that data is ready. Bits 1 through 5 will not interrupt the controller if they go true because the mask was not set for those bits. When data becomes ready, the SRQ annunciator turns on in the display, and remains on, until the controller responds by doing a serial poll, executing the CLEAR command, outputting the ” K” instruction, or entering a measurement from the 3478A. - Line y | 40 50 1 DATA REROY EXANFLE i -he- 25 VERSION 38 ! 3478A AT ADDRESS TE... 60 Re, a ie 70-990 1000 1010 1020-1040 48 О}. Instructs the computer where to go (line Description Outputs the SRQ mask. The “K” command ciears the status register (except bit 1000) when an interrupt (SRQ) occurs on interface 7. ENABLE INTR7;8 actually enables the -hp-85 to respond to the SRQ. SRQ is octal code ”8” in the -hp- 85 control register. These lines contain the main body of the program # This is the start of the interrupt subroutine. SPOLL returns the 3478A status byte to variable ” P”. It also resets bit 6, if it was set, of the status register. The STATUS command reads and clears the -hp- 85 Status/Contro! register so that it can respond to the next interrupt. Line 1010 reads the data and resets bit O of the status register. Line 1020 displays the data. Line 1030 returns program control to where the program was interrupted. pa PA / ео О ба == < ad fed pr + y LA 4 LS E OUEN e "an E MV Example 2. Front Panel SRQ “ The front panel SRQ feature of the 3478A provides you with a way of manually interrupting the controller from the multimeter front panel. This feature is enabled by setting bit 4 of the SRQ mask, command “M207. Once this is done, pressing the 3478A front panel SRQ key causes the 3478A to request service (SRQ) from the controller. The SRO annunciator turns On in the display until the controller responds by doing a serial poll {or the CLEAR command, Of "К” instruction). 49 Line Description 40 The "M20” statement sets the 3478A 10 respond to the front panel SRQ key. The , nk” clears the status register, except bit 07 O. 50 This telis the computer where to go (line 1000) when an SRQ interrupt OCCUFS- | FRONT РАНЕ! SEO EXAMPLE 60 ENABLE INTR actually allows the controller | -he- 6° VERSIÓN to respond to interrupts. ¡ 24754 AT ANDRESS TE QUTFUT 723 "EME 70-990 These lines contain the body of the pro- 0H INTE 7 GOSUE 1964 gram. - | ENABLE INTR 7:8 но The body of the erosraë 30 1000 Line 1000 is the beginning of the interrupt zz here subroutine. The STATUS command reads END _ and clears the -hp- 85 Status/ Control a STATUS €: 1; H register so that it can respond to the next a F=SPOLLCTFZ2: — interrupt. a IF BITC(F. 4) THEN DISP "SKE | | _ KEY FRESSED” | 1010 SPOLL returns 3478A status byte to e RETURN variable P. It also clears the status register. 1020 Bit 4 of the status byte (P) is checked 10 make sure itis a” 17 if it is, the message TT eme —. SRQ KEY PRESSED is displayed. if it isn't, then something else caused-the interrupt. . 1030 This line returns program control to where it was interrupted. i EEE e OU NE, ET AN TI : Do Er rar AE Ele al TAN - прно” . ir ute = En Te pa Sp FLT A NE Te PA A Ta NC Re TT AE Aa aura ar нло я A NA TR aE me TAL TN TT OC RFO TT ae av SPOLL Example Comments Serial poll allows you to determine the current status of the 3478A. When the 3478A receives the serial poll message, it returns its status byte (status register), Many controllers will display the byte as the sum of the values of the individual bits that are set. If bits 7 and O are set, for example, the value would be shown as 129 (129 = 12841) The 8 bits of the status byte and their respective values are shown in Figure 3-5, followed by a description of the bits, Bit 7 power-on Reset Bit 6 sao Bit 5 | Cal Falied Bit 4 Front Pane! SRC Bit 3 Hardware Error Bit 2 Syntax Error ‚Bit 1 N/A (always O) Bit O Data Ready Decimal Value Sepp de, 128 64 32 16 8 Data Ready Bit 1 Syntax Error Bit 2 Hardware Error Bit 3 When this bit is set to 1, “put à reading if it is addre when the controller begi some change in the programmed state Figure 3-5. Status Byte it indicates that the- 3478A will out=-- ssed to talk, This bit will return to O ns fo accept the reading, or when of the 3478A causes the reading to be no longer available. This bit is always O. When set to 1 thi received over the This bit, when it is set to 1 in the calibration RAM. More about the error by reading the and E bus commands). checked every time a rea 50 WF $ bit indicates that a command has been P-IB that is syntactically incorrect. , indicates that a hardware error of Some sort has occurred, This may be the failure of a self test routine, a problem with the A/D converter, or 3 checksum error information can be obtained 3478A error register (see the B The calibration RAM checksum is ding is made. SPOLL (Cont'd) Front Panel SRQ When this bit is set to à 1 it indicates that the front panel Bit 4 SRO button has been pressed. Calibration Fail This bit is used to indicate that an attempted calibration has Bit failed. The bit will be set to 1 under this condition. Service Request This bit indicates that the 3478A has requested service via the Bit © SRQ line. The bit is set to 1 whenever one of the evems specified for bits O through 5 above occurs at the same time , that the corresponding bit in the mask register is set. The bit is also set at power-on time if the PWR ON SRQ switch on the rear panel is turned on. This bit is reset by a serial poll. power-on Reset This bit is set to 1 when a power-on reset has occurred. H Bit 7 switch 3 on the rear panel block of switches is set to the " 1” or up position, bit 6 will be true and the SRQ message is sent. Bit 7 will be cleared if a reset due to the HP-IB CLEAR command occurs or the TEST/RESET key is pressed. It is also cleared when the 3478A is Serial Polled. All status register bits described above are reset by a Device Clear Message. Bits 2 through 7 are also reset by a serial poll if bit 6 was read as a 1. If bit 6 is read as a 0, indicating that the 3478A was not generating an SRQ, no bits are chang- _ed. See also the K command in the Quick Reference Guide. Try this simple exercise. 1. Reset the 3478A. This should be done by cycling the LINE switch. Without setting the SRQ mask, perform a serial poll on the 3478A. Remember to check the command structure for the controller you are using. The status byte returned by the 3478A should indicate that bits O and 7 are true. Many controllers will show a value of ” 129”. Looking at Figure 3-5 we can see that the value 129 is equal to the sum of the decimal values of bits O and 7. Bit 7 is true because of the power-on/reset that occurred. Bit O indicates that a measurement has been made and data is ready. This step of the exercise simply serves to show that bits in the status register may be true without causing the Service Request message to be sent. Remember that when Service Request is sent, the SRQ annunciator turns on. | 51 ha . T [PPE SE FE 2—3 i SPOLL (Cont'd) 2. Now turn the 3478A off. On the rear panel find the bank of 8 switches and set switch 3, Power-on SRQ, to the up (1) position. When you turn the 3478A back on, the SRQ annunciator should be on in the display. Now do a serial poll. The status byte returned by the 3478A shows a value of 193. This means that bits 7, 6, and 1 were true (128+64+1=193), Bit 6 is true because of the power-on SRQ condition. Bit 7 is true, as in the first step, because a power-on reset occured. Because the Power-on SRQ switch was “SET”, when the 3478A was turned on, it sent the Service Request message (SRO).After you do the serial poll, the SRQ annunciator will turn off. 3. Finally, turn the 3478A off and return switch 3 to the down position. Turn the 3478A on, notice that the SRQ annunciator is not on, and send it the message " MO1”. MO1 sets the SRQ mask for the data ready condition. In just a moment the SRQ annunciator will turn on in the display. Again do a serial poll. The value returned should again be 193 (bits 7, 6, 1). This time the SRQ occurred because the SRQ Mask was set for bit O, Data Ready. Do another Serial Poll and notice that the SRQ annunciator goes off momentarily until new data is available, The value returned from this second Serial Poll is 65 because bit 7 was cleared by the first poll, The previous section on Service Request gave two example programs demonst- rating SRO intefupts, Look at the second program, FRONT PANEL SRO. Change line 70 to read: 70 GOTO 60 and run the program. Line 40 sets the SRQ mask to front panel SRQ. Line 1 O00 performs a serial poll when, and Only. when; an SRO-- Condition occurs (ie, when you press the 3478A SRO key). Line 1010 looks at bit 4 of the Status Byte to verify that it was the front panel SRQ key that caused the interrupt. Hy 52 TRIGGER Examples Lo TRIGGER 7 Comments If the 3478A has been addressed to listen, the TRIGGER message (also known as GET, for Group Execute Trigger) will trigger the multimeter for a new reading. if a reading is in progress at the time the TRIGGER message is received, the reading will be aborted and a new reading started. If a reading is in progress when the TRIGGER message is received, there may be a delay (up to 1/2 second) for the previous A/D cycle to be aborted and the new reading to commence. 53 Topics in Advanced Programming The following five programs illustrate the flexibility and Measurement power of the 3478A. The programs include using a thermistor to accurately measure temperature, achieving the maximum reading rate, using the 3478A Status Bytes, and more. Although the programs were developed on an -hp- 85 desktop computer they may easily be modified to run on any other controller. in many cases, suggestions are made for mod ifying the programs to suit your individual needs, TEMPERATURE MEASUREMENTS The program shown in the following figure computes the temperature, in °C, corresponding to the resistance of a thermistor. The program has been designed to work with thermistors exhibiting a 5.000 Ko resistance at 25°C, such as a type 44007 (-hp- part number 0837-0164} or equivalent. The program gives you the option of measurements to be made on the thermi 3478A for a 2-wire measurement which gives suitable results if the thermistor ig | used at a temperature where its resistance is much greater than the resistance of и the test leads. For greatest accuracy from a thermistor, a 4-wire resistance measurement should be used, To change to a 4-wire resistance measurement, J delete the exclamation mark from line 50. The program is useful over a | temperature range of - 80°C to +150°C selecting either 2-wire or 4-wire ohms stor. As it stands, the program sets the 40-50 Line 40 sets the 3478A up for a 2-wire resistance measurement on the thermistor. | TEMPERATURE MERSUREMENT The 3478A is also set to the 30 Kohm 1 WITH TYPE 44887 THERMISTOR range, 4 1/2 digit display mode, Autozero iD on HT Мая т 5 321 Ps BANAT Ty a on, and internal trigger. Line 50 is the | 5001296 ee A 60-80 These three lines contain the conversion | 5 ENTER 200. Em GR ЛИКЕ - Coefficients for the 44007 thermistor, 4=LOGCR GE het 90 Line 90 enters the measured resistance = 5 ЗЫ - ESA from the 3478A, т На a E т 5 En EA 100-110 These two lines Convert the measured 149 END CE resistance to a temperature, 24 Na ER] 120 The calculated temperature is displayed. 130 The GOTO 80 statement returns the program to iine 90 for another resistance measurement, 54 TESTE HhMENUN = й E aa! ee em HE PE EEE 227 Co erminale "E DISPO НОЕ (sa Pause 200005 ment of the parallel resistor combination is "ance to be" input" ú RI=R1iXR2- CRI-RZ) 250 in this line, the value of the resistor is 4 OUTPUT AL © «NoR="; RI але displayed on the -hp- 85 display. EXTENDED OHMS The extended ohms feature is available only via the HP-IB F7 or H7 commands. With extended ohms you can measure resistances above 30 Mohms. When in the Extended Ohms mode, the 3478A goes to the 30 Mohm range, 2wire mode. An internal resistance of approximately 10 Mohms is placed in parallel with the inputs. If this resistance is measured first and then the unknown resistor connected to the inputs, the parallel combination can be measured and a calculation performed to determine the approximate value of the unknown resistance. The formula for the calculation is: AE Ri * Rt Rx = — Ri — Rt Rx is the unknown resistance, Ri is the measured value of the internal 10 Mohm resistor and Rt is the measured value of the parallel combination. The test leads should be a very short shielded twisted pair to not pick up radiated noise. A program that will make the necessary measurements, perform the calculations, and display the value for the unknown resistor, is given in the following figure. 1 EXTENDED OHMS EXAMPLE | -he- 85 VERSION ШИ CLEAR o | Lines Description TEE LA E ire a 10-40 These lines title the program, clear the 11 AT ASS: i 17 TER ESE mA В . ! - ba ALE E TES san -hp-85 display and set the variable Al to O FLES: e DISA: E Fe 723 which is the HP-IB address of the a DISF "Extended ohms is 3 2-w 3478A. ей DISP "measurement for resi =. 50-140 - These lines are-used to make the measure- . ..... rei SE I Нотт RE ment of the internal 10 Mohm resistor. bove 34 Mohns.". 2 015 The actual measurement is made in tine E A et eT 130 and input to the -hp- 85 in line 140. Line 50 displays a message on the 3478A REGS (CONTI TO BE CIN display to open the input terminals. ús DISP “Open” the 24780 ineut t x 150-220 in this set of program lines, the measure- FÉD2HDD RESISTOR a | the measurement and line 220 inputs the Re DISP "Cornect.r OUTPUT AL 1 3 seis measurement to the -hp- 85. mr on Ms CE 230 Line 230 uses the formula above to TED Ymeasured to: he 23475 DISP "measure? a X 5 RTS M. calculate the value of the unknown CDISP “terminals. to resistor. . blak в DISPO | “PRESS LEO 240 The value of the resistor is displayed on à PAUSE О E. the 3478A display in this line. The value QUTPUT Ai SEPT a . is read directly in Mohms. ENTER Al 5 RZ CLEAR Y DISP "THE RESISTANCE IS: "¡R318006;"MOHMS.” END 55 dBm MEASUREMENTS The dBm Program is used to calculate a power ratio using a 50Q impedance as the reference. The dBm equation is: dBm= 10+LOG[(X2/R)/1mw] where X is the measured value, R is the impedance reference (50's) and 1mw is the OdBm reference. Lines Description 30 This line uses the H2 Home command to 4 to the ac volt : | 18 ! dEm MEASUREMENT set the 34784 9 the ac voits made. T1 is 29 | ~HP- 25 VERSION gger. 0 OUIEMT 723. + ue tri EE 40 The ac voltage measurement is input to 28 ENTER 723 5 B - the -hp- 85 in this line, Ze DER EOS BR 50.081) 50 HI5P P В | 50 This line performs the dBm conversion. 79 LOTO 48. LOL DÉS СВ END 60 Line 60 displays the dBm value on the -np-85. 70 This line causes the program to return to line 40 for another measurement, * 56 MAXIMUM READING RATE The maximum possible reading rate is with 3 1/2 digits selected, autozero off, display off, manual ranging, the line frequency switch (347 8A rear panel) set to the 60HZ position, and positive de voltages, current and resistance measurements. Remember though, there is a settling delay on the two highest ohms ranges. The program in the following figure sets the 3478A for these conditions with two exceptions. First, you must manually set the 50/60 Hz line switch to the 60HZ position. This switch is on the rear panel of the 3478A. Second, the program sets the 3478A to the autorange mode. If you know the approximate value of the voltage to be measured you can change the ” ВА” command in ine 50 to reflect an appropriate range. The program accepts 100 readings from the 3478A and stores them into a buffer . B$, When all the readings have been taken the readings aré printed. With the -hp- 85 computer, the 100 readings are accepted in approximately 1.4 seconds. Lines Description 30-40 BS is setup as an 1/0 Buffer to store 1300 bytes of data. The 3478A outputs 13 bytes per reading in the form: +d.ddd- diExd Cr LF. Therefore, for 100 readings the buffer must be dimensioned to 1300. The eight extra bytes are for overhead in the -hp- 85. 50 Line 50 programs the 3478 to de votts, autorange on, 3 1/2 digit display mode, e Lo MARINES READING RATE autozero off, display off. You may want to ag | NP a EUR i а GI Eeciónet слили сти: eo replace RA to reflect an appropriate range. | “TOBUEFER B* DE EA a UT | gi = 60 “The TRANSFER statement is_the fastest 23 ne EHS io possible means to transfer data from the ~~ NSFER 723 ! 0.55 EHD a LON 3478A {address 723) to the 1/0 buffer y AS ATI RETO pad TR gs. FHS is Fast Handshake. COUNT 1300 21 ma 2 BIER 2 2h means that only 1300 bytes will pe ac- ТНТ BsC1>41 ' cepted. euT 723 2" FIRANIZODE © - AB 97 °! Во tog He es ET HE TT Ri SEA 70-80 These two lings set UD two variables, | and J, to pul out individual measurements from BS. | is incremented in steps of 13 hecause the 3478A sends 13 characters per reading. We are on concerned with the first 11 characters though (CR LE is io nored). Therefore, J 18 specified as 10 characters beyond |. so Line 90 prints an individual substring of g$ specified by | and J. 100 Line 100 refers back to line 70 and in- crements | for the next reading. 57 errata pH Aa AT TO eee TO There are 5 bytes, each 8 bit wide, which may be used to determine the current state of the 3478A. If the multimeter is addressed to talk after reception of the "B” command it will Output the 5 bytes, given in the table of 34784 programming Commands, The first of the following two programs demonstrates how to get the binary representation of the 5 bytes. The second program shows how the first three bits of the first byte may be used to indicate the measurement function the 3478A is set to. Similar steps may be used on the remaining bits and the other 4 bytes. Status Bytes Program Lines Description 18 1 BINARY STATUS EXAMPLE 28 |! —he- as VERSION 38 ! Z4TSp ADDRESS = FAZ 44 ОНТРОТ 723 ¡E 29 ENTER 723 USING "ООВ"; Bi 'EZLBZ, BY, BS GO DISP "BYTE 1=";BITCB1,75;681T repo ¿BITBL. 5) RITA. 4 71 rele BITCRIL 2) RIT (RY. LS :EITcB1. a) 40 ей DISP "BYTE C=" BITCRE, 79, BIT Teba А ВТТЕВ2, 5) ; ВГТеВ2 4 Tee 3 BIT(B2, 2), RI Tche 16 50 Output its five statys bytes, The B command instructs the 3478A to The five bytes are entered into variables EITBS,a | 28 Disp "BYTE SS"; BITCB3, 7) ; ВТТ BIT CDS SS BIT BE ann rE 0 BIT(RI 2), BIT (hy de JBEITORZ, ay ; ЭВ GISp "BYTE 4=";BIT(E4,7>;BIT Teno? ¿BITCB4.5>:BI1TIB4.47 TRA.) :BITR4,23:BITCh4 15 BITCRY, > 188 ОТ5Р "ВУТЕ SE ВТТЕВ5, т); ВТТ HEBT CDS US BIT CB ann 60-100 B81 through BS. Pa Each line displays the individual bits of one | byte. ENTES DEE PEITCES,e) 18 ! 34708 STATE PROGRAM 28! epee E VERSIÓN 28 ! 24760 ADDRESS = a 1 F=f С a8 OUTPUT 723 ¡"a Sa ENTER "23 USING “SIB " ; El ra IF BIT(B1, 73 THEN F=4 28 IF BITCB1.65 THEN F=F+5 IF GIT(B1.55 THEN F=F41 IF F=1 THEN Gt="DC VOLTS: IF F=> THEN L$="AC VOL TE" IF F=3 THEN G$="2-WIRE QHZ IF F=4 THEN G$="4—-WIRE UHMS * iF F=5. THEN GE="DC AMpo: IF F=g THEN GE="AC AMPc: IF F=7 THEN G$="EXTENDED OHM sa 178 PRINT 83 PRINT 158 END Ne } En ben Lal PO pas PS RNS LIT a 5 168 "FUNCTION: "iG% 70-90 100-1680 170-189 58 Measurement Function Program Description Line 40 sets Up variable F. AS in the other program, these two lines call for the status bytes, The three highest bits of byte 1 are tested and F is valued accordingly, The value of E is tested and G$ assigned. The value of GS is printed. ay 3478A Programming Commands An invalid range for — _— Type | Command | Explanation Measurement Function Fi DC Volts function F2 AC Volts function F3 2-wire ohms function F4 4-wire ohms function FS DC Current function F6 AC Current function F7 Extended ohms function Range В -- 30mV DC range Ro 1 300mV AC or DC range or the 300mA AC or DC range RO 3V AC or DC range or 3A AC or DC range RI 30V AC or DC tange or the 30 ohm range R2 300V DC or AC range or the 300 ohm range R3 3K ohm range | RA 30K ohm range R5 300K ohm range RE ЗМ ohm range R7 30M ohm range RA | Selects Autorange a given function defaults to the most sensitive range if the range specified is too low, or the least sensitive range if the specified range is too high Display N3 Selects the 3 1/2 digit display. Fastest reading but little noise rejection. .1 Power N4 Selects the 4 1/2 digit display. 1 PLC integration. N5 Selects the 5 1/2 digit display. Best resolution and greatest noise rejection. 10 PLC integration. | Trigger Ti Internal trigger T2 External trigger. Any reading in Progress is aborted, and the 34784 waits for an external trigger pulse to Occur. Triggering occurs on the negative going edge of the pulse, Readings may also be initiated by an НРАВ GET command. T3 Single Trigger. This Causes a single measurement to commence. Further readings may be initiated by an HP-IB GET Command, but not an external trigger pulse, T4 Trigger Hold. Any reading in progress is aborted and the 347 8A remains idie. The 3478A wili stili respond to an HP-IB GET command but not to an externa! trigger. T5 Fast Trigger. Fast Trigger works the Same as T3, except that in AC Volts, AC Current, or the two highest ohms range the initial settling delay is omitted. i more than gne reading is necessary because of auto-ranging or if the DMM must change ranges or functions to perform the Measurement, the delay will occur nor- 59 347 8A Programming Commands (Cont'd) Autozero ZO 21 Write To Display D1 D2text D3text Preset Commands H1 H2 H3 H4 HS H6 H7 Explanation Autozero off Autozero on Meturn From D2 or D3 to NORMAL DISPLAY. The "D2” command places the message “text” into the 3478A dispiay, The Message can contain any of the 64 ASCI characters from decimal 32 through 95, inclusive, The message may be ag long as necessary to fili Up the 12 characters in the display. Note that the period, Comma, and semicolon go between characters. This Command is terminated by any contro! character, such as a <CR>. If more than 12 characters are Sent, the extra characters are ignored un- tl a control character js received. If the terminating contro! character ig anything but an HT, LF, VT, FF, or CR, it will result in a syntax error. This command also locks the display umtil an error occurs, a D1 command is received, a device ciear is received, or a front panel Key is pressed. Like the D2 Command above, this places the Message ” text” into the display, it aiso turns off all dedicated annunciators and then Stops updating the display, This command takes about 30ms to complete, after which the considerable overhead of updating the display is bypassed (means a faster reading rate}. This enables the 3478A to respond to commangs more rapidly in certain Conditions. If the display i$ not updated for about ten minutes, it will blank out Completely. The display can be restored by Pressing the ” LOCAL” key, or by executing a D1, D2, or D3 command, Home command. This command -places-the -347 SA -intó the DE Volts function, — Auto-Range, Single Trigger state, 4 1/2 digit display, with Auto-Zero on, Any result ready to be output to the bus or display is erased, The external trigger input is disabled. This command is equivalent to FITAR- 2RAZI1 Na”. Measure AC Volts identical to #1 except for the function. + Measure 2-wire Ohms. !denticai to H1 except for the function, Measure 4-wire Ohms, identical to H1 except for the function. Measure DC Current, identical to H1 Except for the function. Measure AC Current, identical to H1 except for the function, Measure Extended Ohms, Identical to M1 except for the function CC] a SEA ek IE re 60 — Le ееедииые | = 3478A Programming Commands (Cont'd) Type Command Explanation Binary Status Binary Status. If the 3478A is addressed to talk after reception of the “B” command, it will output five bytes which indicate its currently programmed state, This command also clears the error register {byte 4}, The meaning of the five bytes is: Byte 1: Function, Range, and Number of Digits, If Octal value of bits 7,6,5 = then DC Volts then AC Volts then 2-wire Chms then 4-wire Ohms then DC Current then AC Current then Extended Ohms il ~~ DO RW AN 0 +— If Octal value of bits 4,3,2 = 1 then 30mV DC, 300mV AC, 30 chm, 300mA AC or DC, Extended Ohms = 2 then 300mV DC, 3V AC, 300 ohm ЗА AC or DC = 3 then 3V DC, 30V AC, 3K ohm then 30V DC, 300V AC, 30K ohm then 300V DC, 300K ohm then 3M ohm then 30M ohm 4 E on 4 IF Octal value of hits 1,0 .. о ‚then 5 1/2 digit mode... ... = 2 then 4 1/2 digit mode = 3 then 3 1/2 digit mode Byte 2: Status Bits Bit 7 = Always zero Bit 6 = 1 then External trigger enabled Bit 5 = 1 then Cal RAM enabled Bit 4 = 1 then Front/Rear switch is in the front position Bit 3 = 1 then 3478A is set up for BOHz operation Bit 2 = 1 then Auto-Zero is enabled Bit 1 = 1 then Auto-Range is enabled BtO = 1 then Internal trigger is enabled Byte 3: Serial Poli Mask (SRO) Bit 7 fl + then PON SRQ switch was on the last time power was turned on or a device clear Message was received Bit 8 = Always zero Bit 5 = 1 then SRO if CAL Procedure failed Bit 4 = 1 then SRQ if keyboard SRO is pressed Bit 3 = 1 then SRQ if hardware error OCeurs Bit 2 = 1 then SRQ if syntax error OCCUTS Bit 1 = not used Bit 0 = 1 then SRQ as every reading is availabe to the bus 61 ar Chapter IV Maintenance Operators Introduction Your 3478A Digital Multimeter was thoughtfully engineered for ease of use, accuracy, and perhaps most important, reliability. The instrument was carefully inspected before shipping and should be free of mechanical and electrical flaws and should be in proper electrical working condition. The information in this chapter covers the initial setup and installation of the 3478A and should be read before the 3478A is installed for use. This chapter also includes the specification table, warranty information, instructions about what to do if you suspect the multimeter is malfunctioning, obtaining repair service, cleaning, etc. Accessories Table 4-1 lists the available accessories for your 347 8A. These accessories are of-. fered to help you maximize the usability and convenience of your 3478A. Table 4-1. Accessories | Accessory Number Description OOZ3A Temperature Probe or oh 10631A yP.IB Cable, 1 Meter {38.37 inches} 10631B HP.IB Cable, 2 Meters 178.74 inches) 10631C HP.IS Cable, 4 Meters (157,48 inches) 106310 HP-IB Cable, 0.5 Meters {19.88 inches) 11000A Test Leads, Dual banana both ends 110024 Test Leads, Dual banana to dual alligator 1100354 Test Leads, Dual banana to probe and alligator 110968 RF Probe 34111A High Voltage Probe 34118A Test Leads, banana to probes with safety guard rings Option 907 Front Handle Kit (5061-1088) Option 308 Rack Mounting Kit {5061-0072} Option 910 Additional Operators Manual and Service Manual, -hp- Part Number 03478-90000, 03478-90001 63 Batt a E бо AP TEE EA ОЛетя Initial Inspection Your 3478A was carefully inspected before it left the factory. It should be free of mars or scratches and In proper working order upon receipt. You should, however, inspect the instrument for any damage that may have occurred in transit. If the shipping container or cushioning material is damaged, it should be kept until the contents of the shipment have been checked for completeness and the instrument has been mechanically and electrically inspected. Procedures for checking the electrical performance of the 3478A are given in the 3478A SERVICE MANUAL (-hp- part number 03478-90001). if there is any mechanical damage or the contents are incomplete, or the Instrument does not pass its performance tests, notify the nearest Hewlett-Packard office (a list of the -hp- Sales and Service Offices is located in the back of this manual). If the shipping container is damaged, or the cushioning material shows signs of stress, notify the carrier as well as the Hewlett-Packard office. Save the shipping materials for the carrier, Preparation for Use Power Requirements The 3478A Digital Multimeter requires a power source of 100, 120, 220, or 240 Vac (-10%, +5%), 48 Hz to 440 Hz single phase. Maximum power consump- tion is 25 VA, Line Voltage Selection Refer to the rear panel of the 3478A for the line voltage option label. Make cer. tain that the option marked on the label is the same as the nominal line voltage for Your area. Also check the left Most switch (50/60Hz Switch) for the proper setting, Le., up for 50Hz and down for 60Hz, Table 4-2 lists the available power options. Table 4-2. Line Voitage Options - Option No. | Line Voltage Frequency Power Line Fusa & 218 100 50 250 mA {-hp- part number 2110-0004) 316 100 60 250 mA 325 120 50 250 mA 326 120 60 250 mA 335 220 50 | 125 mA (-hp- part number 2110-0318)+ 336 220 60 125 mA 345 240 50 125 mA 346 240 60 125 mA | * sio-blo fuse 64 CAUTION, e Before connecting the. multimeter to: añ.ac power source, verify. that the ac. po wer. source ‘matches ‘the por wer requirements of the multimeter as. marked on the option abel on: о rear o the instrument. Only qualified. service ved personnel are al ; hie 34754, for Power Cords and Receptacles Figure 4-1 illustrates the different power cord configurations that are available to provide ác power to the 3478A. The -hp-part number shown directly below the individual power plug drawing is the part number for the power cord set equipped with the appropriate mating plug for that receptacle. If the appropriate power cord is not included with the instrument, notify the nearest -hp- Sales and Service office. 250 Y 250 Y 250 V 250 V OPERATION OPERATION - OPERATION OPERATION PLUG*: SEV 1011.1959-724507 PLUG *: CEÉ7-V11 PLUG*: C£E272-V1 PLUG": DHCR 107 TYPE 12 CABLE: HP 8120-1682 CABLE": HP 8120-1880 CABLE": HP 8120-2956 CABLE*: HP 8120-2104 125 - GA" 250 Y 250 Y 250 у. бА** 125 V - ВА** OPERATION OPÉRATION ` 1 : > PLUG* NEMA 1-15P PLUG*: NZSS 198/AS C112 PLUG": BS 13534 PLUG*: NEMA G-16P PLUG"; NEMA 6-19Р CABLE®: WF B120-0684 CABLE": НР 8120-0696 CABLE®: MP 8120-1703 CABLE*: HP 8120-0688 CABLE": HP 8120-1521 STD-B-4195 [ev-! “The number-shown for the plug le the industry identifier for the plug only. Thea number shown Sor the cabla is ah HP par muriber tor a completa cable including the plug. +" listed for use in the United States of America Figure 4-1. Power Cables Grounding Requirements To minimize shock hazard, the instrument chassis and cabinet must be connected to an electrical ground. The instrument is equipped with a three-conductor ac power cable, The power cable must either be plugged into an approved three- contact electrical outlet or used with a three-contact to two-contact adapter with the grounding wire (green) firmly connected to an electrical ground (safety ground) at the power outlet. The power jack and mating plug of the supplied power cable meet International Electrotechnical Commission (IEC) safety standards. 65 e тыл vn ewes Pd TA E . Inc Safety Considerations General safety precautions must be adhered to during all phases of operation of the 3478A. Failure to comply with these precautions or with specific warnings elsewhere in this manual, violates safety standards of design, manufacture, and in- tended use of the instrument. Hewlett-Packard company assumes no liability for the customer's failure to comply with these requirements. This is a Safety Class 1 instrument. | | Operating personnel must not remove instrument covers. Component replacement must be made by qualified maintenance personnel. Do not Operate the instrument in the presence of flammable gases or fumes. Operation of any electrical instrument in such an environment constitutes a definite safety hazard, Warnings or cautions precede any potentially dangerous procedures throughout this manual. Instructions contained in the warnings and cautions must be followed. Safety Symbols used on the instrument or in the manual include the following: WARNING The WARNING sign denotes a hazard. it calls attention to a procedure, practice, condition, or the like, which, if not correctly performed or adhered to, could result in injury or … death to personnel. CAUTION y he CAUTION sign denotes a hazard. It calls attention to | an operating procedure, practice, condition, or the like, which, if not correctly performed or adhered to could result | NOTE The NOTE sign denotes important information. It cails attention to a procedure, practice, condition, or the like, which is essential to highlight, AN Instruction Manual Symbol: the product will be marked with this symbol when it is necessary for the user to to gefer to the instruction manual in order to protect against damage to the instrument, Indicates dangerous voltage (terminals fed from the interior by voltage exceeding 1000 volts must be so marked). Alternating current. Че Direct current, 66 Environmental Requirements When the 3478A is calibrated, careful note should be taken of the ambient temperature. In order to meet and maintain the specifications listed in Table 4-3, the 3478A should be operated within + 59°C {+ 9°F) of the calibration temperature, also called the reference temperature. As it comes from the factory, the 3478A should be operated within an ambient temperature range of 23°C | +5°С (73°F +9°F), The instrument may be operated within an ambient temperature range of O°C to 55°C (+32°F to 131°F) but with reduced accuracy. To prevent potential electrical or fire hazard, do not expose - Specifications The specifications for the 3478A are the performance characteristics of the instrument which are certified. These specifications are listed in Table 4-3, and are the performance standards or limits against which the multimeter is tested. Included in. the table are some supplemental characteristics of the 3478A and should be con- sidered as additional and general information for you, the user. Because of the many operational capabilities of the 3478A, exercise care when checking the instruments specifications. Any changes in the specifications due to manufacturing changes, design, or traceability to the National Bureau of Standards will be covered in a manual change suppiement. interface Connections The -hp- 3478A is compatible with the Hewlett-Packard Interface Bus {HP-1B}, HP- IB is Hewlett-Packard’s implementation of IEEE Std. 488-1978, ” Standard Digital interface for Programmable Instrumentation.” Refer to Appendix A for specific information regarding HP-1B. 67 x + © ur i 1 x = 3 E i i ni à rw. The 3478A’s HP-IB connection is made by an HP-IB Interface cable to the 24 pin HP-1B connector located on the rear panel. A typical interconnection of HP-1B 15 shown in Figure 4-2 in which system interconnection is made by three interface Cables. The ends of the cables have both a male and a female connector to enable connections to other instruments and cables. As many as 15 instruments can be connected by the same interface bus. However, the maximum 'ength of cable that can effectively be used to connect a group of instruments should not exceed 2 meters (6.5 feet) times the number of instruments to be connected, or 20 meters (05.6 feet) total, whichever is less. Ea connection Address Selection — The HP-IB "address of the 3478A is determined by the setting of the five right- most switches on the rear panel. These switches are read at power-on, whenever the ADRS key is pressed, or whenever an HP-IB CLEAR message is received over the bus, Turning on (up) all five switches selects the 3478A Talk-Only mode. The 3478A normally leaves the factory with the address switches set to decimal code “23°. The corresponding ASCII! code is a listen address code of “7” and a talk code of "W”. Refer to Figure 4-3 for the factory address switch setting. - 4 Fuse Replacement Amps Terminal Fuse The Amps terminal fuse is located physically inside the Amps (A) terminal on the multimeter front panel. To replace the fuse, first remove the cable from the Amps terminal and then turn the power off to the multimeter. Use the side slots on the “A” terminal to rotate the terminal counterclockwise. The terminal and fuse will 68 e ‚ “a æ rom OO m protrude from the front panel. Remove the terminal and fuse, replace the fuse with a 3A/250V rated fuse, -hp- part number 2110-0003. Return the terminal and fuse to the front panel. Power Line Fuse The power line fuse is located on the rear panel of the 3478A in the lower right corner. To replace the fuse, turn the multimeter's power switch off and remove the power cord from the rear of the instrument, With a small fiatblade screwdriver rotate the fuse terminal counterclockwise. Replace the fuse with the appropriate fuse as shown in Table 4-2. Reinstall the fuse and terminal and apply power. 3478A DVM N ADDRESS Shown at Factory Default Address 123), This number is called the Primary Address. ASCH Code Character Address Switches 5-bit Listen ” Talk | A4 A5 AD A7 AB | Decimal Code > Y 22 | 2 Jam Factory Default 24 25 26 27 28 29 30 Select Codes Can be any integer 1 mu 12. Primary Addresses can be any integer O thru 30, 31 is not a valid HP-IB address. ‚2 ое со = С) ORNS ET PP NAXELCANDOVOZEMAET ! — Talk Only Vou Ae O 1 O 1 O 1 O 4 О 1 о 1 0 1 O 1 о 1 O 1 о 1 0 1 O 1 о 1 O 1 0 1 Figure 4-3. 3478A Address Codes 69 Va TR - АЗ In Case of Trouble If at any time you suspect that the 3478A is malfunctioning, perform the self test as foliows: TEST/ RESET SGL TRIG This initiates the functional self test of the 3478A. The self test starts by turning ON every segment in the display (except the top dot on the colon) for about 2 Seconds. Following this the self test actually begins with any discrepancies noted in the display. If there are no self test failures, the HP-IB address is displayed and the 3478A returns to its power-on state. The following is a list of possible self test failures: press: М.С. ВАМ FAIL - This indicates the internal microcomputer (U.C.) RAM (not CAL RAM) has failed its self test. UC, ROM FAIL - The 3478A has failed its internal ROM self test. UNCALIBRATED - The RAM that contains the calibration constants has an incorrect checksum, the calibration of the 3478A is suspect A:D TEST FAIL - The A/D converter has failed its self test. Y A:D LINK FAIL - The microprocessor cannot communicate with the If the Voltmeter self test fails, or the display is blank, or it will not respond to the front panel keys (3478A not in REMOTE mode), turn the multimeter off and perform the following steps. | 1. Remove the HP-IB connéctor, External Trigger, Voltmeter Complete and power cables. | | # 2. Check the Line Voltage option marking on the rear panel of the 3478A to ensure that it is set to the correct nominal line voltage in your area (ie., 110, 120, 220, or 240 Vac). 3. Ensure that the correct power line fuse is installed and that it is intact, 4. Check the AC power cord and plug it into the AC receptacle on the 3478A. 70 C + 5. Turn the 3478A on. Watch the display. At turn-on the multimeter will display SELF TEST, then the HP-IB address, and then start taking readings in the de volts mode. If any part of the self test should fail an error message will be shown in the display instead of the HP-1B address. 6. If the display does not return Or if the self test fails again, the 3478A requires service. Notify your local -hp- Sales and Service Office for specific information on where to send the instrument for repair. Remote At the end of this chapter is a program that you can use to verify the operationai readiness of the 3478A, Although the program was written for the -hp- 85 computer, the attendant flowcharts may he used to convert the program to run on other computers. The program was not designed to troubleshoot the 3478A but the information gathered by running the program can be a great help In troubleshooting. | Before running the program make certain that the 3478A is the only instru- a | | o . RERQUE ALL INSTRUMENTS ment on the Bus. Remove the test — МНН СО ENCEPT 3470. . DA E ы leads and external trigger and VM В KEYS DURING THIS TEST 34798 VERIFICATION PROGRAM complete cables. Follow the instruc- E BEE RL AE a Es TUE tions given on the CRT. м FROM THE 3478A. TEST PROGRESS 1S SHOWN ON THE | DISPLAY, ERRORS ARE NOTED он , | THE PRINTER. PRESS ECONTI KEY Response: Press the ” CONT” key JERE UE | WHAT IS RDDRESS OF THE 34788? Response: If the address of the MES ea ad 3478A is 723, then just + press the END LINE key. li the address is different, enter the new address (3 digits}, and press END LINE. E A 71 PRESS TEND LINE KEY — — 4 mu a ce EE i SELE TEST itl LTTE Response: Press the 3478A SRO ! TESTING FRONT PANEL SRG key. The calculator will | continue to beep every 10 seconds until the Key is — MIES pressed. Ë | - PRESS UE Na NN Response: You will be asked to dd От TEST watch the 3478A display MER RANGE. FUNCTION, as it completes the | RUTDZERD TEST er. . PRESES DISPLAY TEST verification. The final ll PASSES TRIGGER TEST ; nd: ' EBSSES PRESET COMMANDS TEST “Ap-85 display indicates À SATT that all tests passed. FEX VERIFICATION COMPLETE say ¥ EHD OF VERIFICATION PROGRAR x y What the Test Does Test 1. SELF TEST, This test verifies that the 3478A responds to the HP-IB CLEAR command and performs its internal self test. | Test 2. PROGRAM CODES. The test starts by verifying that the 3478A can send an SRO and that the com. puter will respond to it. Next, an illegal code is sent to the 3478A to be certain that it rejects it. Then, all possible combinations of autozero, function and range Codes are sent to the 3478A. In addition, all display modes, trigger modes and the preset commands are tested. Finally, two readings are taken. One from the the 300V de range that is checked to be sure there are no offsets. The second reading checks for an overload condition from the 2-wire ohms mode. 72 A reg - Warranty Information Certification Hewlett-Packard Company certifies that this product met Its published specifications at the time of shipment from the factory. Hewlett-Packard further certifies that its calibration measurements are traceable to the United‘ States National Bureau of Standards, to the extent allowed by the Bureau's calibration facility, and to the calibration facilities of other International Standards Organization members. Warranty This Hewlett-Paékard product is warranted against defects in material and workmanship for a period of one year from date of shipment. During the warranty period, Hewlett-Packard Company will, at its option, either repair or replace products which prove to be defective. For warranty service or repair, this product must be returnéd to a service facility designated by -hp-. Buyer shall prepay shipping charges to -hp- and -hp- shall pay shipping charges to return the product to Buyer. However, Buyer shall pay all shipping charges, duties, and taxes for products returned to -hp- from another coun- try. Hewlett-Packard warrants that its software and firmware designated by -hp- for use with an instrument will execute its programming instructions when properly installed on that instrument. Hewlett-Packard does not warrant that the operation of “the instrument, or software; or firmware will be- uninterrupted -or error free. _ _ ... ... Limitation of Warranty The foregoing warranty shall not apply to defects resulting from improper or inade- quate maintenance by Buyer, Buyer-supplied software or interfacing, unauthorized modification or misuse, operation outside of the environmental specifications for the product,or improper site preparation or maintenance. NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. HEWLETT-PACKARD SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 73 Exclusive Remedies THE REMEDIES PROVIDED HEREIN ARE BUYER'S SOLE AND EXCLUSIVE REMEDIES. HEWLETT-PACKARD SHALL NOT BE LIABLE FOR ANY DIRECT, IN- DIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY. Assistance Product maintenance agreements and other customer assistance agreements are available for Hewlett-Packard products. For any assistance, contact your nearest Hewlett-Packard Sales and Service Of- fice. Addresses are provided in the back of this manual, How to Obtain Repair Service Most -hp- service offices in the United States are NOT authorized to service and repair 3478A DMM's, Contact your local -hp- sales office for specific information on where to send the instrument for repair. This will substantially reduce turn-around time. You may have your 3478A repaired by Hewlett-Packard anytime it needs service, whether it is under warranty or not. There is a charge for repairs after the one year warranty period. A list of sales offices is conveniently provided in the back of this manual. Outside of the United, States, repair service may be obtained at your local -hp- service center, ; Serial Number ~~ Each 3478A multimeter carries its own serial number on a plate on the rear panel. It is recommended that owners keep a separate record of this number. Should your unit be lost or stolen, the complete serial number is often necessary for trac- ing and recovery, as well as any insurance claims. | “3 General Shipping instructions Should you ever need to ship your 3478A, be sure it is packaged in a protective package {use the original shipping container and cushioning material) to avoid in- transit damage. Such damage is not covered by the warranty. Hewlett-Packard suggests that you always insure shipments. Attach a tag to the instrument identifying the owner and indicating the service or repair needed. include the model number and full serial number of the instrument. In any correspondence, - identify the instrument by model number and full serial number. 74 FEA зе e LA mare Further Considerations Cleaning Disconnect the 3478A from its ac power Source before cleaning. The multimeter can be cleaned with a soft cloth dampened either in clean water Of in water con- taining a mild detergent. Do not use an excessively wet cloth, or allow water inside the instrument. Do not use any abrasive cleaners, especially on the display. Do not press too hard on the display. The panel area surrounding the input terminais should not be touched because oils on the surface caused by finger prints. may cause leakage paths and decrease the input impedance. To maintain the high input impedance of the multimeter, the input terminal area should be cleaned periodically with a cotton swab dipped in isopropy! alcohol. 75 3 bd 23 lt —u = pepe " 7 a! E EG EA E Ea ET НЕ: = re AN Ent + UE ESS FA e EE т mms: 118 128 уе fa] E 148 1 I ed pg 1 че sf rat iy К af, E pe: je A at E ETT — 1 =A pd “ sr = i т, 1 Ры KY a! per +. Pi F ERE a du of Pub po E PS i |+ Lh ot EnF =. } Ey 21% rn, fd EE a TE à ad re rt > mr! = inj | r за Г. Г +} Fit a x ti pea 7 T5 es PR La Cod £a} La] + ad Lo “J ery LI hal ta] Ena! O dl mu ir a TF + Fa La i Ld —_ SE LE id Las SE Verification Program and Flow Chart Y 11 | 2€ € Ef + [А > nn == . bo — art a ! + aL ZA TT pp ah jee TA ACER WERIFIOST ION жеж DARE VERS Ir OCT PRE CLEAR a LET IS 18% PRINTER To os MA TE om Tg TE 25575 128 1 INSTRUCTIONS | LEE За i TE € TEST - ОПОР тов ово” SUIT TÉ 1 PROGRAM CODES ert С TER "pg CAT - ir RIFI — E {mn se же e + | в еб к = Ti pr Lines 10-40 ; LISP "Xx Eh mir - ERE E EXC DF VERIFICATION FR DEM El Program Title and Simple = H i" Overhead, MISA " 3a Pe 1 ~ - PROGRAM" в prep? IFIO 16 OISP " 4 REMQUE - UMERHTS ВОВ hove ou pers Line 50 1 HE | - ;fr "id Dn CRCERPT 34720 on HE BUS Go To Subroutine For In- тер сы TNA. structions, 3478A HP-IB “i = a ) PO HOT PRESS ah Address In Variable D1. A AH ККМ m y = 73 THIS TEST" SETA DURING 155 8 | - E. a UNTIL IHSTRUCTENT Line 60 — O 00 ag - - ine PET 1 - A =F , N _ >. REMOVE ALL INPUT gol To Subroutine For Self „CHBLEE FROM THE 347 Et конь TT a iE 13 A T 7 A ERE TE Dun T НЕ = En - A tat fad H id bi . N О 1 0 Е р Le ar ponñne à | Display Error Messa + E, y : Kar ! jfi SS ERRORS ARE H And Abort Verification, Pr aay Г о го bt orf к CYT. 2 $ E FT y a i Er В THE x - ; o FE he: hi ITER E тт se, ONTI KEY Y RES EC TES HISF "TH porta a LAER" TO BEGIN. F Я й 5 E Line 70 Tor = TER кЫВ an a. Be To Subroutine For Pro--- 7m a La lt " i = Na уч, р gram odes. BAPE ! - ADORE: = > ol THE DISPO" CFACTORY ADORESSera: E DISP E DISP * presse Ri | 1 ME КЕ кл = i * ot = 7 fr i [1=723 - = | Display Failure M 1=72z | _ essage HH ERAN GO To Sen And Abort Verification. g +4 ever rte TE e a FI à Vi € „я Jr - in Fad ve bet 5 ET , HE E - “ot Г H E HI {1 1 mil Fi бел: IN tas FPL Lo lF M _ О . Lines 80, 80, 100 | E NT a TE TN A } DE dl FY pe gy TI ef IF FRODID 538 THEM mec IF (me YE Ma ДНЕМ = = = Display Verification Pass- IE Ay An MSIE THEM 3 E ed Message, 2668 | CUT UE 1 т LE PEUT) == A de men = Le + LE ET "че rls tb TES ¡BE | ERROR Line 11° E End 3478-4F FE INVALID INPUT gar a tE r =P E BEER SOTO 248 Hi т mu = Al ГГ] Ce 7 76 FT TG 1} ru ““arification Program = ны Вов EN fo tal fod bes р ВД + Jo La "À i “| CF ea de a + a am ESA illa Pr 1 Liu rufa ео NENA Jet Роз не О НИ i un UE LA fi Ja £s] o END a Tn ETA H 74) £5) Hd Г] ES rit] a ne | + E a PC a a Ena E 114 17% mes poh PUE ия 1 Ta RÉ Cf, ET ET Cr NA Ja 17 mi e ET + -.1 END CURS LA 7 E CE E anh — E Lh - +] + о E ds Wa OTSP YEE i | ОП SELF TEST CLEAR CIS "SELF TEST" SET TIMEOUT D; 166688 OH TIMEOUT 0 GOTO £34 PORO RK MOWER FROM LY CLEAR DI HAIT свай QUTRPOT E ENTER Di. A OFF TIMEOUT DO TE R=0 THEN GATD 650 IF EITCA,ET=1 THEH OTE " Pal RAM FAILURE" TE EIT<CA,17=1 THER ISP" cad FRILURE (MOT CAL RAM" ТЕ BITCA,.CSo=1 THER ISP © ROM FAITLURE" SITCA,Ei=1i THEN CISP и S00 SLOPE ER ROE" ETTCA,AdI=1 THEN DISF " Mm SELF TEST FAILURE" EITCA,Hi=1 THEM OISF " { THE FAILURE" port bq + + “TT Ti + - " - AIEP " SELF TEST FAILED. SEE | 34758 SERVICE MANUAL” DISP E CISP " XX HERIFICATIC H REORTED 4%" ISP E STOP CLEAR Y BEER" E PRINT "THE GE MICE AT AUDRESS VEVALE CDI 2. PRINT "CIF AMY: FRILS TO RES FONO," @ OISF PRINT "ЖЕ VERIFICATION REORT EG 4" ® OISF PRINT "CHECK FOR FROFER HF-1 В AOCRESS PRINT "AND RLM THE PROGRAM A HALO" то 1 SELF TEST PASSES ¢ SELF TEST PASSES 44 RETIRA and Flow Start Self Test Subroutine Chart (Cont'd) Lines 410-450 initialization. Set interface To Timeout if 3478A Does Not Respond in 10 Seconds. Lines 630-680 Timeout Occurred. Instru- ment At Address D1 Fail ed To Respond. Line 460 "Clear D1' Causes The 3478A To Do A Power On Reset. Line 47C Wait 2 Seconds For 3478A To Complete Power On Reset. Lines 480, 490 - Check 34784 Error Register. _— Life TO" e НА = 0, № Errors Lines 690-710 SELF TEST Passes. | ~~ Display Message And Return To Main Program. Lines 520-570 Check Bits In Error Register And Display Ap- propriate Massage. Lines 590-620 SELF TEST Failed. Verification Aborted. CD 77 3478-4F E -# T I |: Н + a ' a I: Tow [HE wl o VE in i, à DE i = # Ë й i : x + de don + E 1 Lo MT 1x 4 A 1 ï - ! "5, RCE а ВЫ E it i H mei Rae] = PP RE Aie ea === PE E RT OEI E Verification Program and Flow Chart (Cont'd) a ay SUBROUTIHE FOR PROGRAM COD ET $k TES A ln im неон SFOCTESTIMG FRONT FRNEL SR “a — VE FUR LRAN" IH A -- TF} i 4 FL} РА a mes aa Г. ITE LET [++ j HEME BRE A TIMERS 2, 202960 COTO зая HA INTRO DO COTO STA EHRELE INTRO О; ОРОРОВ CISF @ DISF "PRESA 73 SEA FRONT FÄAHEL SRE KEY" Е FFF WHIT MATT FT a a LL hE * rl mar PU Sa i PD ee mi LE оке A A a A Fa Por fa E LT 01 3 "O1 ii “ HIDISFLAY TES a чин = er El = ЗЕ) т го Ра CA Ia fe 1 wy] TT ET ET we a I FEE CE 5 Ft A nö A AU USUTSPLRY TEST" ' —_ “= Ш wd rf 1 < п — ей CI ++ у — pl Je A eh for Foo ap Ha СЛ fr FRENTE (та — er TE Pra —q id ME e £5) E OT 756 | Sai Sl SEE ESP PASSES GISPLAY т Zig BEEP m COTO FRE ms Cie 228 OFF TIMER# 2 Lez 5 COR T=1 To 5 238 STATUS ©.1 ; A 1200 E=4 240 QUTPUT Di 086" 1318 OUTEUT O1 ¿"Fa RAOINST HT 255 EMTER 01 USING "ICIES" : 81, 1328 HesT 7 Be: Bi 1338 QISP " PASSES TRIGGER T SES IF GITC(EZ.45 THEM #90 _ ET" ; 878 PRINT “FROMT PANEL Seg HOT A a FUE H=7 TO ÿ STEP 1 CEMOHLEDGED® E c= Er 1 fra XX UISF @ DISF PEE UERIFICATION ASORTEO" e STOP A DISR “XX FRONT PANEL SEN FRE | Lime ASSES РЕЕЗЕТ С DEEP 244 FRONT EANE RO PA ANOS à ES PRESET CO | SRR KEY HOT PRESSED 3 CUTRUT E FRINT "SAO KEY HOT PRESSEN | Y 8 OPRINT >= 662 ANO 7C BAS THEN PRINT "a VERIFICATION RAEOE нара Las = ae 420 “TERO ERROR © > STOP Bh RANGE" TOR UN THE За CISF 6 DISP ECOISP "TESTING 1458 PRINT “UERIFICATION HOT ABO FÜR PROGRAM CODES" RIED" a ONTENT Ci ¿EMBES" SUTEUT O1 :"FZRA" de IMTR OC GOTO 1607 ENTER 01 : 0 ENABLE INTE os | IF 029995090000 THEN PRINT OUTENT 01 "02% | ILLEGAL CO OHM OVERLOAD ERROR" e FRI GE 7 HT CVERIFICATION HOT AEQRTE ia et kek pa pd fa ТЕ Га тар Раф р} E AA EE — me AD x EF Li "a" зу: Ч Ha 1 bald "a Ei tE $. Je po Joo Fa Pad pu 1 па 0 AT] EU né à pa ay ! on Tt Ae E J 1 Li r 15 pa ni + Er bin Ja val ma E put. je > Ja 44 E Ea т — oF CH £a Chr TR ds AM mai La LL Li Là 714 CA i 390 WAIT 1890 + WAIT FOR SEC LU? 1808 PRINT "SENT ILLESAL CODE AH 1470 QUTELIT Hl 1 "F1RGuETçn 000 FéPagt La La a aa LL tame DER " READINGS TEST FR 11 FRIMT “ACCEPTED IT 1 maza por! um ot Ad m A} er A = т DIF EXE VERIFICATION ABORT La 149€ En Ea = STOF ie | ERROR HEROUTINE 1620 STATÚS 0.1 a 1519 STATUS Di. 1948 PESPOLLCÓN LESA TR BITS I) (1958 DISPO" FASSES ILLEGAL € 1536 IF EITC, 2: THEM PRINT "PRO LU cri PERA TEA A | A ID DD a : RAM CODES TEST FRILED. дтн | 248 FRIMT “SYHTRR ERROR" :® PRI Lal a T4 1a E Dona Pr + 4 1 Cri À a. EE; Я с +4 pe CA ta Зо еб еч I TI FR, mi Arr ri + Er + {о Et En XK] fe Sera À : HT e MTR 0 SE {510 1756 IF E=1 ТНЕН FRIHT "FURCTIOH ет ет TR 1.5 COUE= FMF ¡El NA ATA H LE IHTR [ME эру, ALTOZERÓ= 207€ LODE = В | OZERO Зе IF Een THEM PRIMT "DISPLE РОН Con. GIGITS = MH" 4-1 157009 IF E=2 THEN PRINT CRISE Sy R=-3 TO 7 | RANGE CODES TENIANDS FAITLURE" BUT DL "ZW Zi "FRE RY; 1550 IF E=4 THEM PRINY “TRIGGER о. COMMAND TT SFE IF E=S THEM PRINT «pera - COS = WH © 1 FRESET E IGP E CISP “3% MERTETCATIC = RANCE, FU NH ORBORTED ЖЖ" AAO HOT ICH. AUTOZERN TE 1519 STOR Em о je pa bh A Fr AA] Hs E LO EEN] VF ETRE CTL AT pea que Fol punta ma 3 CA 5 3 a e Ma da fo Fm 4 Tel Te] 4 mod fod TE HA FF - = Ek E A e tea рень $ ma Qu pd EN + = E Tv Lit Li Ti #— NE AC Tn i Ts LE + uJ ed] TU: £1 ba /8 Varification Program Start Program Codes Subroutine Line 740 Get SRO Mask For Front panel SRO Key. Lines 7 50-770 Enable SAO interrupt. Linas 780-81 5 Beep Every 10 Seconds Until Key ts Pressed. Line 030 | Status Command To Clear SAO Register. Lines 900-830 SHO Key Not Pressed. Something Else Caused SHO. varification Aborted. Lines 540-560 Test ox à Of Status Bvte 3 for Front Panel SAC? сане splay Front Panel SRA "Passed. Lines 940-1 480 Program Codes Test Lines 990-1070 ; Lines “840-1020 Send Mega! Program Syntax 1037. Check For Failure? FAIL As E gA78A Accepted Неда! Abortad PASS Lines 1020-1050 4478A Generated SRO | For litegal Syntax. = RE Syntax, Ver freatron + and Flow Lines 1080-1 ago | Test Program Codes For: Autorero, Range, Func tions, Display, Trigger, end Home Comments. — mm EE Lines 1070-1600, 34744 Generated Syntax - Errar For Valid Hyntax Verification Aborted. L 1090-1160 Test Autozero, Function And Range? nes 1270-1270 Test Dispiay Cornmands? nas 1280-1320 Tast Trigger Commands? PASS Lines 1170- 1200 Test For Number Of Dispiay Digits? ines 1340-1370 Test Home . Commands? | PASS Lines 1390-1450 Readings Test, 79 Chart (Cont'd) ines 1380-1420 Test For 300 VDC Range Zero 7 Lines 1440-1 460 Test For ObmE Overload? Lines 1470-1480 Verification Complete Return To Main Program. ror, Aborted. Print: Zero Error, Verith cation Not Aborted. Print: Ohms Qvericad Er Verification Not 3478-4F An de IO Table 4-3. Specifications 4% and 3% Digit Mode: input Characteristics: Maximum Reading Resolution Range 18% Digit) 5% Digit 4% Digit 3% Digit 30mv + 30.3099mV 100nV uv 1OuV 300mV + 303.099mV uv iO V 100uV 3 Y +3.03099 у 10 V 100V mv 30 V + 30.3099 yv 1GOuV imv 10mV 300 Y + 303.099 V 1mV 10mv | 100mV Input Resistance: 30mV, 300mV,3V ranges: > 1010 30V, 300V ranges: 10MO + 1% Maximum laput Voltage: (non-destructive) Hito Lo: 303V rms ar 450V peak Hi or Lo to Earth Ground: +500V peak Measurement Ассигасу: + (9% of reading + number of counts) Auto-zero ON 5% Digit Mada: Cal. Tamp + 1% Cal. Tomp. +5% Range 24 Hours 30 Day 1 Year 30mV | 0.030 + 41 0.040 + 41 0.044 + 41 300mV | 0.007 + 5 0.020 + 5 | 0.019 + 5 3 V ¡0006 + 2 0.019 + 2 | 0.619 + 2 30 V | 0.007 + 3g 0.020 + 3 | 0.019 + 3 300 V | 0,008 + 2° 10.020 + 2 | 0.019 + 2 DE YOLTAGE Auto-Zaro Of: (5% digit} for a stable environment { + 1 110 counts to accuracy specification counts for 300mV and 30V ranges, range, Temperature Coefficiant: °C), for <24 hrs, add for 30mv range, 11 3 counts for 3V and 300V OC to (Cal, Temp. —-5°C} (Cal, Temp. +5°C} to 55°C 5% digit display, auto-zero ON + (% of reading + number of counts)/® С Range Temperatura Coefficient 30mvV 0.0028 +5 300mVv 0.0005 + 0.5 3 V 0.0004 + 0.05 30 V 0.0006 + 0.5 300 V 0.0004 + 0.05 Noise Rejection: in ds, with 1kQ imbalance in Lo [ead B0Hz + 0,1%. Auto-zero ON. . AC rejection for 50, 1 AC | AC 1 De Display | AMR ECMR | CMR 5% digits 80 140 140 4% digits 59 120 140 3% digits о 60 140 Maximum Reading Rates: (readings/sec) First reading is correct within .1 count of final value, when on Correct range, triggered coincident with step input. The reading rates are dependent on the speed of the controller being used, Co Accuracy. is the same-as-5 A digit mode-for-% of reading; use Maa ee ma me me em E BEAT bn wn mena =о- e 1 count for number of counts on all ranges except 30mV Line Auto Resolution range use 4 counts, Frequenes Zaro | 3% Digits | 4% Digits | 5% Digits The Cal. Temp. (Calibration Temperature) is the temperature Off 71 33 4.4 of the environment where the 3478A was calibrated, Caii- GOHz On 53 20 2.3 bration should be performed with the temperature of the он 67 30 37 environment between 20°C and 30°C. ' ; : 50Mz On 50 17 1.9 Input Characteristics: AC VOLTAGE(true rms responding) Maximum Reading Resolution Range {5% Digit) 5% Digit | 4% Digit | 3% Digit 300mv 303.099mV TV 10uV 100uV ОЗ у 3.03089 Vv 10uV 100uV 1mV 30 V 30.3099 V 100uV 1mV 10mV 300 V 303.099 V mv 10mv | 100mV Input Impedance: TMQ + 1% shunted by <60pF Maximum Input Voltage: (non-destructivel Hi to Lo: 303Vrms or 450V peak Hi or Lo to Earth Ground: +500V peak Measurament Accuracy: $ + {9% of reading + number of counts) Auto-zero ON, 5% digit display. Accuracy is specified for sine- wave inputs only, > 10% of fuli scale, 1 Year, Cal. Temp. +59C Ranges Froguancy 308mV 3V, 30V 300V 20Hz-50Hz 1.14 + 163 1.14 + 102 1.18 + 102 50Mz ~ 100HZ 0,46 + 163 0.46 + 103 0.5 + 107 . 100Hz — ZOkHz 0.29 + 163 0.26 + 102 0.33 + ¥ 20kHz — 50kHz 0.56 + 247 0:41 + 180 0.55 + 1. 50kHz ~ 100kHz 1.74 + 882 1.05 + 8265 1.26 + 825 1GOkHz — 300kHz 10.1 + 3720 30Y range only! 80 Table 4-3. Specifications (Cont'd) AC VOLTAGE {true rms responding) {Cont'd} Aute-Zero Off: Common Mode Rejection: {5% digits) for a stable environment (+1 SC), for < 24 hrs, add 10 With 1k0 imbalance in Lo lead, > 70dB, de to Вонг. counts to accuracy specifications for all ranges. Maximum Reading Rates: [readings/sec) Temperature Coefficient. First reading №8 correct within 79 counts of final value, when On 56 10 (Cal. Temp. geC),¡Cal, Temp. + 59°C) to 55°C, correct range, triggered coincident with step input. Add 0.6 seconds for 5% digit display, auto-zero ON. each range change. Cor frequencies <20kHz, +10.01 6% of reading + 10 counts) °C For frequencies > 20kHz, +{0.04% of reading + 10 counts) *C Reading rates are the same Es de volts using fast trigger (TE). Using Nor- mal Trigger (T1, T2, T3k Crest Factor: , For 50 or 60HZ operation, auto-zero ON or OFF. >4:1 at full scale. 2% or 4% digite: 1.4 - 514 digits: L RESISTANCE (2.wire Q, 4-wire @) input Characteristics: 2 Wire Ohms Accurary: Same as 4-wire ohms, except add a maximum oí 10010 oft set. On the 3MQ range add an additional offset of 0.0016% 3% Digit of reading. On the 30MQ range add an additional offset of Maximum Reading Resolution Range {5% Digit 5% Digit 4% Digit 0.0083% of reading. 30.3099 € 10000 300 Q | 303.099 a 100m Auto-Zers Off: зо ко 00 ка 10 © . 15% digit) for a stabie environment (+ 1° C1, for < 24 hrs., add , 110 counts to accuracy specification far 300 range, 11 counts 300 kil 303.099 КО 100 8 . for 3000, 3 counts tor 3KQ through 300KQ ranges, 8 counts | змо | 3.030990 J ЮГ За голое, and 33 counts for 30ME range. 30M 30.3099MU 10 ki = input Protection: (non-destructive Temperature Coefficient © Ror + 2 ; o wi source to Lo source: + 350V peak 0°C to (Cal. Temp. -5 Ch. (Cal. emp. +89) to 55% . 5% digit display, auto-zero ON Hi sense to Lo sense: + 350V peak + 1--% of reading + number of counts) °C wi or Lo to Earth Ground: + 500V peak 7 M easurement Ассигасу: Range Temperature Égefficient Auto-zero ON. 4-wire ohms. нос _-_ 3008... ._| 0000S + 5 3k — 300kUA 5.0009 + 705 - 3MG 0.0021 + .08 5% Digit Mode: зом 0.021 +05 Cal. Temp + 1% Cal, Temp. +5°C Current Through Unknown: Range 24 Hours | 30 Day | 1 Year Range: 200, 3000, 3k, 30K, 300K, BMA, SOME Current: mA IMA, 1MA, TO0xA, 104,11 1008A 308 0.023 + 35 0.027 + 41 | 0.034 + 41 3009 0.0045 + 4 0.012 + 5 0.017 + 5 Maximum Open Circuit Voitage: 3k— 300k0 0.0035 + 2 0.011 + 2 19.016 + 2 3M8 0.0082 + 2 0.011 + 2 0.016 + 2 6.5V 30M9Q 0.036 + 2 0.066 + 2 {0.078 + 2 Maximum Reading Rates: Same as de volts, except for 3MO aná 30M ranges. For 3MU range, add 30ms: for 30M range, add 300ms par reading. >» Input Characteristics: DC CURRENT M : Maximum pasurament Accuracy Reading Resolution + {% of reading + number of counts) Hange 15% Digit) 5% Digit | 4% Digit 3% Digit Auto-zero ON + 303.099mA TRA | 10pA | 100A Cal, Temp. +5% 3 A +3.03099 A 1 ОрА 100 А 1mA Range 30 Days — | 1 Year Maximum Input: (non-destructive! 300MA 0.11 + 40 | 0,15 + 40 ЗА, < 1A input 0.14 + 6 0.17 + © 3A from < 2 50V source, fuse protected 3A > 1A input 10 +3 10 +30 81 Table 4-3, Specifications (Cont'd) DE CURRENT (Cont'd) Auto-Zero Off: Rangs | Temperature Coefficient (5% digit) for a stable environment {+ 1°C), for < 24 hrs., add 300mA 0.012 + 5 110 counts to accuracy specification for 300mA range, 11 3 A 0.012 + 0.5 counts for 3A range, | Maximum Burden at Full Scale: iV Temperature Cosfficient: OC to (Cal. Temp, - 5° С) [Cal Temp. +5°C) to 55°C o 5% digit display, auto-zero ON Maximum Reading Rates; + {% of reading + number of counts)/°C Same as de volts AG CURRENT (true rms responding) Input Characteristics: Auto-zaro Off: Maximum (6% digits) for a stable environment {+1 °C}, for <24 hrs, Reading Resolution add 10 counts to accuracy specification, | 5 4 Mas mios у Range 5% Digit 5% Digit | 4% Digit 3% Digit Temperature Coefficient: 300mA 303.099mA TRA 10uA 100A 0°C to (Cal. Temp. - 5°C}, (Cal. Temp. + 5°C) to 55°C, 3 A 3.03099 A TORA: 100A 1mA 5% digits, auto-zero ON. о ‚ + 021% of reading + 10 counts)/?C Maximum input {non-destructive Шо 3A from <250V source; fuse protected | |, «um Burden at Fall Scele: { 1V Measuremant Accuracy: - + (% of reading + number of counts) Crest Factor: Auto-zero ON, 5% digit display, accuracy specified for sine- wave inputs only > 10% of full scale. 1 YEAR, CAL, TEMP, +590 >4:1 at full scale Maximum Reading Rates: Ranges Same as ac volts Frequency 300mA | ЗА 20Hz-- 50HZz : 1,54 + 163 | 2.24 + 183 50Hz-— 100HZ ‚81 + 163 1 1,5 + 163 100Hz—1kHz 81 + 163 | 1.5 + 163 1kHz-10kHz | .72 + 163 | 1.42 + 163... 1. 1 1 LL 1 12000 — TOkHz- 20kHiz .B6 + 163 1 1.58 + 163 GENERAL INFORMATION Operating Tamperature: OQ to 55°C Power: AC Line 48— 440Hz:; 86--250V, (see configuration) Humidity Range: 35% R.H., O to 40°C Maximum Pawer: < 12 watts Ca Storage Temperature: | Size: "40°C 10 75°C 102mm H x 215mm W x 356mm D Warm-up Time: (4 in H x 8 in Wx 14 in D) 1 hr. to meet ali specifications. Weight: Integration Time: 3Kg (6.5 lbs.) | Line Frequency Number of Digits 50H: | 608: 5% 200ms 166.7ms 4% 20ms 16.67ms 3% 2ms 1,667ms 82 iy HE eT ATN {= 12 SHIELD-CHASSIS GROUND — APPENDIX A Introduction This appendix contains a general description of the Hewlett-Packard Interface Bus (HP-18). HP-1B is Hewlett-Packard's implementation of IEEE Standard 488-1978, "Standard Digital Interface tor Programmabie instrumentation”. The information is non-controiler dependent but, where appropriate, is dependent on the 3478A. General HP-IB Description The Hewlett-Packard interface Bus (HP-1B) is a carefully defined interface which simplifies the integration of various instruments, calculators, and computers into systems. The interface provides for messages in digital form to be transferred between two or more HP-IB compatible devices. A compatible device can be an instrument, calculator, computer, or peripheral device that is designed to be interfac- ed using the HP-IB. Mec ei Capri pee Eg AE ge The HP-IB is à parallel bus of 16 active signal lines grouped into three sets, according 10 function, 10 interconnect up to 15 instruments. Figure A-1 provides a pictorial view of the HP-1B connector and its pin designation. A diagram of the interface Connections and Bus Structure is shown in Figure A-2. 219) “yhe 5478 contains mic threaded HPIB cable matt LINE re ads as opposed to English threads. Metric © ded hp. ото “106314, Bor C HP-1B cable Hockserews. mu 5108 “secure the cable to the instrument. ldeniices De “pes of mounting stds nd ockscrew< is a Dos ‘English threaded fasteners ar colored silver and £01 ed fasteners are colors ‘black. DO NOT male REN “fasteners t10.each ol ror thie threads El + ith 6 | PAY destroyed, Metric threaded НР 1B cable ha) 7 | NAFD ahd part nurabers tallo TE Re ER g | NDAC ; LOCKSCREW LONG MOUNTING STUD SHORT MOUNTING STUD 9 IFC . 4380-064 0380-0644 10 | SRQ 1 390 0360 80-06 2 0644 En 8 | | 8.5mm CT 4 Smm Ё ©} A 18 PIO TWISTED PAIR WITH PINE = 19 | P/O TWISTED PAIR WITH PIN Y THESE PINS = it 2 HA: à e E + E E E NE 2 i 13 y > = a 3 5 st = = E o “ed fasteners are colored = e - ——T E A. NA ES AE ey {A а = 21 PIO TWISTED PAIR WITH PIN © INTERNALLY 22 | PIP TWISTED PAIR WITH PIN 10 GROUNDED 20 | PIO TWISTED PAIR WITH PIN 8 ARE т | { 23 | 5/0 TWISTED PAIR WITH PIN 11 7a | ISOLATED DIGITAL GROUND Figure A-1. HP-IB Connector 83 DEVICE A ABLE TO TALK, LISTEN AND CONTROL e.g. GEVISE B ABLE TO TALK AND LISTEN te. ETA DATA BYTE TAANSFER CONTROL - l'HANOSHAKE | LINÉS DEVICE € ONLY ABLE 70 LISTEN E. EGEL | MANAGEMENT [CONTROL LINES SEAL LO + DEWYICE © ONLY ABLE TO TALK CEO 1-68 DAN NRFO NBAC IFC ATH SAO REN £04 Figure A-2. interface Connection and Bus Structure Eight Signal lings, termed as DATA Lines, are in the first set, The Data Lines are used to transmit data in the form of coded messages. These messages are used to program the instrument function, transfer measurement data, coordinate instru- ..Ment operation, -an cl +0-manage-the- system.- This-allows- vou to- set-up the instryg-- .-- ment and read its measurement data. Input and Output of meaasges, in bit parallel byte serial form, are also transferred in the Data Lines. A 7-bit ASCII code normally represents each piece of data. Data is transferred by means of an interlocking ” handshake” technique which per- mits data transfer (asynchronously) at the rate of the slowest active device used in that particular transfer. The three DATA BYTE CONTROL lines, coordinate the transfer and form the second set of lines. The remaining five GENERAL INTERFACE MANAGEMENT lines are used to manage the devices on the HP-IB. This includes activating all connected devices at once, clearing the interface, and others. For a detailed description of the HP-IB lines, commands, internal operations, etc. refer to the HP-IB Abbreviated Description Manual, -hp- part number 5955-2903. A condensed description is also available in the Condensed Description of the Hewiett-Packard Interface Bus Manual, -hp- part number 59401-90090. The manuals are available through your local -hp- Sales and Service Office. 84 o" HP-IB System Overview and concepts used to describe HP-1B “ The following paragraphs define the terms (Bus) system operations, + HP-IB System Terms specify: which device WwW tion, Addressing may also be accompli formation or only rece “ge il ent by a controlling device 10 receive that informa- B and which devicels) will a. Address: The characters s shed by hardwiring a device to only send in- | send information on {пе НР-! ive information. tion consisting of 8 binary digits (bits). b. Byte: A unit of informa ble with the IEEE Standard 488-1978. c. Device: À unit that is compati d. Device Dependent: An action a device performs in response to information iB. The action is characteristic of an individual device and may 5 * sent over the HP- vary from device to device. ocate a device that is used by a controller to | e, Polling: This process typically two types of polling, as follows: nteract with the controller. There are of operational information s must be repeated for needs to | 1. Serial Poli: This method obtains one byte about an individual device in the system. The proces each device from which information is desired. © 7" parallel Poll: This methods-obtains_ information about a group of devices does not respond to a Parallel Poll. 7 7° simultaneously. The 3478A tion Capabilities Basic Device Communica us can be classified into three Devices which communicate along the interface b basic categories: UP.IB when it to send information Over the Hi be active at a time; usually the one that a. Talker: Any device that is able calculators and computers are has been addressed. Only one talker may directed to send data. All HP-IB type is currently generally talkers. the HP-IB, when they have Devices which receive information over ce may or may not be both a talker and a listener, hb. Listener. nerally both a talker and a listener (at different been addressed. A devi Calculators and computers are ge times). 85 ¢. Controller: The device that can specify which device(s) on the bus is a talker or listener. There can be two types of controllers, an Active Controller and a System Controller. The Active Controller is the current controlling device. The System Controller can, however, take control of the HP-IB even if it is not the Ac- tive Controller. There can also be only one Active Controller at a time, even if several controllers are on the Bus. HP-IB Messages Different types of information can be passed over the HP-IB to one or more devices. Some of this inforamtion is in the form of messages, most of which can be separated into two parts. One part can be classified as the address portion specified by the controller and the information that comprises the messages. The second part can be classified as HP-IB management messages. These message are comprised of twelve messages and are called Bus messages, a. Data: The actual information (binary bytes} sent by a talker to one or more listener. The information (data) can either be in numeric form or a character string. b. Trigger: The Trigger message causes the listening device or devices to perform a device dependent action when addressed. C. Ciear: The Clear message causes the listening device(s) or all the devices on the HP-IB to return to their predefined device-dependent state. d. Remote: This message causes the listening device(s) to switch from local . front panel Control to remote program. control. when-addressed-to listen. — - - - - - - . . . . . e. Local: This message clears the REMOTE message from the listening device(s) and returns the device(s) to local front panel control, f. Local Lockout: This message prevents a device operator from manually in- hibiting remote program control. | | g. Clear Lockout and Set Local: With this message, ali devices are removed from the local lockout mode and revert to local. The remote message is also cleared for all devices. h. Require Service: A device can send this message at any time to signify the device needs some type of interaction with the controller. This message is cleared by the device's STATUS BYTE message if the device no longer requires service, 86 ¡ Status Byte: A byte that represents the current status of a single device on “4e HP-IB. One bit indicates whether the device sent the require sevice message and the remaining seven bits indicate optional conditions defined by the device. This byte is sent from the talking device in response to à ” Serial Poll” operation performed by the controller. j Status Bit: A byte that represents the operational conditions of a group of devices on the HP-iB. Each device responds on à particular bit of the byte thus identifying a device dependent condition. This hit is typically sent by devices in response to a parallel poll operation. k, Pass Control: The bus management responsibility is transferred from the active controller. to another controlier by this message. E E Lee o # | «Abort: The system controller sends this message to unconditionally assume controi of the HP-IB from the active controller. The message will terminate all bus communication but does not implement the CLEAR message. 3478A Bus Capabilities ; The 3478A interfaces to the HP-IB as defined by the IEEE Standard 488-1978. The interface functional subset which the 3478A implements is specified in Table A-1. Table A-1. 34784 Device Capability Si Source Handshake complete capability AH1 Acceptor Handshake complete capability ОБ с Basic talker, with serial poll, talk only | mode, and unaddress with MLA, TEO No extended talker | i LA Basic listener, unaddress when MTA i LEO No extended listener i: 581 Service request complete capability i RL1 memote-Local complete capability ОВ PPO No parallel poll capability DC 1 Device Ciear complete capability DTH Device Trigger compiete capability | CO No controller capability | 87 HP-IB Worksheet The HP-IB worksheet {Table A-2} can be used to determine the HP-iB capabilities of the other HP-iB compatible instruments in a system. The sheet may be filled in with the bus Message applicability for your controiler and for each HP-IB device. The bus Capability for the 3478A has already been filled in. Refer to your controller manual and the manual(s) of your other devicels) for their Bus Message Capabilities. Once the sheet is filled out, you should then have the HP-iB capabilities of your device(s). | Table A-2 HP.IB Worksheet Message Device : | a INSTRUMENT MODEL MOBEL IDENTIFICATION 3478A LISTEN AND YES LISTEN : TALK TALK HP. iB YES o ADDRESS 5 BIT 5 Bit VALUE 22 VALUE DATA S&k TRIGGER R CLEAR A LOCAL R ; REMOTE R LOCAL я LOCKQUT CLEAR LO & R SET LOCKOUT - "SERVICE STATUS $ BYTE STATUS N BIT FASS N CONTROL | АВОЯТ N # |. | | | a |S = SEND ONLY = RECEIVE ONLY S$ & R = SEND AND RECEIVE N = NOT IMPLEMENTED 88 Pus Message Implementation | Messages using the 3478A. The codes used in the figures are: T = True F = False X = Don't Care oct = Octal Code fessage (Controller to 3478A). Trigger Message {fram Controller to Device(s]) 3 Data from the controller to the 3478A first: rst: To send the TRIGGER Message (Group Execute Trigger): Bus Management Lines ATN| IEC | SRO | REN | EOI т Ех т Хх Bus Management Lines АТМ | IFC eno REN | EOL | Tle т | x Sent gn Data Lines Sent on Data Lines 2U7 ? U7 oct010 reat unison | E 7 Universal Unlisten 3478A Listen Address : Universal Unlisten Trigger Command | Controller Talk Address Controller Talk Address 3478A Listen Address . Bus M t Li ; ; us me en я | | | Remote Message В ATNi iFC | SRO REN : EOI | | ET FT x 7 | x To Enter the REMOTE Mode: | | - Bus M t Li x Sequence on Data Lines = ema === a oo | ATNÍ ЕС | sro | ren] Eo i ; Instrument _ В В В ТРЕХ IT Ex 1-2 ‚Program Codes EE o e o DT TT Sent on Data Lines ОО | o nue (3478A to Controller or Other | В Universal Unlisten = L 3478 Listen Address 5215 Controller Talk Address nd Data from the 3478A to the controller, first: > To Remain in the REMOTE Mode: __ mam pe np нк = wi HE HEE mmm mmm wom HE = Bus Management Lines ATN| lec | SRO| REN | EO T | F1 x x IX Bus Management Lines ATN] ect sro ren] eo: Fr 1 ri x 1 x IX Sequence on Data Lines TIA INCAS « En ah Local Message Universal Unlisten J | Lcontroiter Listen Address To enter the LOCAL Mode: 3478A Talk Address | | | | E. o Bus Management Lines | | | | ‘ AIN irc| sno | ren | eoi - TiIFRixitTie EE IC re SR rca Bus Management Lines — Sent on Data Lines "e o - 1001 sé АТМ | ¡EC | SRO | RENT £0 - 24 7 eci991 io F | Ё X | X | X Universal Unlisten Go to Local instruction Controller Talk Address 3478A Listen Address - Sent on Data Lines ( do Output DATA from 3478A 89 wl ET Bus Message implementation (Cont! d To send the CLEAR Message: | To send REQUIRE SERVICE MESSAGE: Bus Management Lines * ` Bus Managemaent Lines . ÇÛ — ATN| IFC | SROJRENJEO! ATN | IFC | SRQ | REN | EO TLE] XX |X хх т | хх "Sent on Data Lines | oct004 Local Lockout Message Clear Command To enable LOCAL LOCKOUT: To send the CLEAR MESSAGE Only to the 34784: В Bus Management Lines АТМ | IFC | SRQ |REN| EO Bus NV anagement Lines = | Е | y, | = | = ты id era REN | EO! a ; FF X (TX | a. Sent on Data Lines oct 021 Local Lockout instruction Sent on Data Lines ? 6 ос! 004 Universal Unlistes | Clear Command 10 maintain LOCAL LOCKOUT: 3475A Listen Address Tm , : Bus Management Lines Status Byte Message | | ATN | IFC | SRQ |REN | EO! To Seria! POLL the 3478A (obtain Status Byte): X 1X { x TX Bus Management Lines “ATN] arc | SsRO LAEN | EOL ° ТРЕЕ ХЕХЕ Clear Lockout/Set Local Message Sent onpata Lines To CLEAR LOCAL LOCKOUT and set LOCAL: ? 6 cct030 W5 Universal! Uniisten kn ce —— 34788 Listen Address! ___ Serial Poli Enable — Bus Management Lines . ontrofler Listen Address | _ !3478A Taik Address. LL... e ma. ATNTUIEC.LSRO [REN TEOL. 2 о X X X ji T | X a wm — then: ” Bus Management Lines | Abort Message ATN | ЕС | SRO*IREN | EOL . ; To send the ABORT Message: РР Хх | ХЕ Bus Management Lines Dos | 5 | | ATN | 1EC | SRQ | REN | EOI 3 Sent on Data Lines | | X + X | X | X — 3478A Status Byte | *f SRO was true, E wil switch-to the false state. and finally: Bus Management Lines ; ATN | IFC | sRQ | REN | EOI FÜ] OF} Sent ón Data LIN coe ress A pe pr RR Pct 031 ` ÿ + | T-Serial Poil Disable 90 ~~ APPENDIX B ASCII Character Codes EE EQUIVALENT FORMS asc EQUIVALENT FORMS ASCHE EQUIVALENT FORMS ASCH EQUIVALENT FORMS Binary Detal = Dec. Char. Binary Gotl Dee Char, Binary Octel Dec, Char. Binary fetal: Due. Г 00000000 600 0 space] 001 00000 040 32 e 01000000 100 64 ' 01100000 140 96 00000001 001 1 1 00100001 041 33 A | 01000001 101 65 , 8 |. 01100001 141 97 00000010 002 2 - 00100010 042 34 8 01000010 102 66 5. 01100010 142 98 00000011 003 3 # 00100011 043 36 € 01000011 103 87. с 01100011 143 | 89 00600100 004 4 $ 00100100 044 36 D 61060100 104 68. d 01100100 144 100° 66000101 006 5 % 00100101 045 37 E 91000101 105. 69 8 QT100101 145 101 00000110 006 8 02100110 - 048 38 F 01000110 106 70 f 01100110 146 102 00000111 007% 1:7 ; 00100111 047 38 S | 01000111 107 7 g | 01160111 447 103 00001000 010 8 090191090 050 40 H 01001000 110 72 h | 01101000 150 104 00001001 071 8 } 99101001. 051 41 | 01001001 111 73 ! 01101001 151 105 00001010 012 10 + 00101010 052 42 J 01001010 112 74 i 01101010 182 108 B 00001011 013 11 + 09101011 053 42 К 01001011 113 ds "k 01101013 183 107 00001100 014 12 ,Ç 00101100 054 44 L 01001500 114 76 ! 01101100 154 108 00001101 015 13 . 00101101 055 45 M 91001101 115 77 mi 01101101 155 109 \ oro 016 14 00101110. 088 46 . «М 01001110 116 78 вор 01101110 156. 110 : 00001111 017 15 / 00101111 057 47 © 01001111 117 78 8 01101141 157 111 00010000 — 020 18 o 00110000 060 48 Р 01010000 120 80 р 91110000 +60 112 00010001 021 17 1 00110001 061 49 Q 01010001 121 81 q 01110001 1617 113 ‚ | 90010010 022 18 2 00110010 062 50 R 01010010 122 82 r G1110010 162 114 | 000i0011 023 18 ‘ a | 00110011 063 51 S | 01010011 123 83» | omo 163 118 Л 00910100 ‚024 20 4 00110100 064 52 T 61616100 124 BA Я 01110100 184 118 < 00010101 025 21 5 90110101 085 53 U 01010101 124 as u 01116101 185 117 | wl 00010110 026 22 6 00110110 068 54 \ 01010110 128 86 м 01110110 166 118 00010111 027 23 7 00110111 087 65 Wl 91010111 127 87 w 01110111 187 118 N 00011000 030 24 8 00111000 070 56 01011060 130.88 X 01111006 170 120 00611001 03 25 9 | ecit1001 07 87 .. Y | 901011001 131 69 Y 01111001 171 121 B 00011010 032. 28 00111010 072 58 01011010 132 so z 01111010 172 - 122 3 $ 00011011 033. 27 : 00111011 073 89 91011011 133 91 { 01111011 173 123 Ko 00011100 034° 28 < 001717100 074 o 01011100 0134 92 | 01111100 174 124 ' 00011101 035 29 a 90111101 075 61 01011109 135 93 } 01111101 175 125 00011170 036 30 > 00111110 O78 62 ^ | 01011110 136 94 - 01111110 176 126 WL 037 51 ? 00117111 0077 637 01011111 137 85 DELL 01111131 177 1297 91/92 a AE E ETE Pore fede beh LEE EAL тоя a rb = mur Erika mad om mmr COMMAND QUICK REFERENCE GUIDE Beep ER aE Range Code Function Coda ° #2 R-1 RO Ri #2 #3 #4 RS AS R7 RA | {Autorangel DC Voits F1 30mv 300mV 3V 30V 300V + + + + + AC Volts F2 * 300mV 3V 30V 300V +. + + + + 2-W Ohm F3 * * * 300 3000 3KA 30KG 300k 3M0 30M0 4-W Ohm rá » + * 300 3009 3KQ 30KA 300KQ 3MG 30MO DC Amps F5 * 300mA 3A + + + + + + + AC Amps F6 * 300mA 3A + + + + + + + Enhanced —F7 | | Ohms Notes: _ * indicates that the range code selects the lowest {most sensitive) range for that function Bo 4 = # ' ` dla - * + “indicates that the range code selects the highest (least sensitive) range for that function Other Program Codes: Function Mnemenic Quaiifier Description | Example N 3,4,5 Selects the number of digits of | N3 selects the 3 1/3 digit display | | display | т. 1-5 “Trigger mode; internal External, T2 selects external trigger Single, Hold, Fast в | 2 o — Autozero ВЕ ВЕ | 1 20 tums Autozero off 5 0 o 10 € 21 turns Autozero on Do. 1-3 Display | D1 selects normal display Détext prints message “text” on ces LIL рву, dd Lee ! H ‚0-7 Home (preset) | HO=F1T4R-2RAZ1N4 HI =FIR-2RAZ1N4T3 H2=F2R-2RAZ1N4T3 H3=F3R-2ZRAZIN4AT3 НА = FAR-2RAZIiNATI: HE =F5R-2RAZINAT3 HE =FER-2RAZ1N4T3 H7 =F7R-2RAZ1N4T3 B Output Binary status с Calibrate (see service manual) i к. Clear serial poll register ; kr read and clear error register ° Мхх 0 to 77 | Set SRQ mask to octal e {octal} | value xx € ; 5 Return value of Front/Rear switch | 93/94 - x " ' + Ви . 7 , 1 . . Page | ° Page H T message.......%4e420 4000. .B7,91 Hints, programming. ...h.020 00000000 0 0 48 mai multimeter readings.........+.. 13 Home commands......44 44404 4 24 à 0 a 6e 4 +. 38 SOFries. . ....c.srrevecrerreeer ee BR see also Table 3-1, and Quick Reference | Guide BAL + ee TU НР-1В Senne na OR general description. ..................83 ss [HP-IB). ...... ...e.serxiar..24,36,37,08 interface connections. .....es..ceec...B783 terminal. . ..re.rereera cara reo. AN Program Codes... 280045050555 565 250 0 058 ACTEtOIS LL 222 ener aaa esas iT worksheet . 6.444 42 4 4 4 4 4 0 84 50 1 4 + + 63 character set, , vo vse enews os 9 a. ange..... 421 | £Bresis. + vv ven hese ead) | FOTO LL 1 44 0 44 44 a 4 4 4 0 4 04 0 00 50 4,818 Input terminals. ... 244424 0 0 4 4 0 0 4 11 0 4 0 4 Integration 1244 444005 44 4 4104 0000 16,18 internal trigaer.... 4240464 444 040 + << 80 | @ FAUON LL Le A 4 da a 0 10 0 04 eee 4,10 L NA. Ea , . | | Я ооо 43,88,90 Line voltage selection. ..................84 Set Local. ...........:44,86,90 LOCAL 1.44 4 4 6 14 4 640 4 + 5 4 ++ un. 44,86,89 Le a LOCALLOCKOUT................4486,80 ; | | O; . - . "oa , ; Co . ‚ a | о LT В ; . ‚ " a 10° . > г | . . ; , . В on 5 , ST Lh E , Manual ‘ranging... 442444 44080 00 0 0 0 22 , RER ER KK 86,59 Measurement Function keys...............4 a 155806. , Cte te A 4 A 4 aa eee 37 Messages sor 1 3dy SRQ.. 110024 1400 a 0080 60 000 000 88 display. ..10 2104002 Tea a ae a see aa 13 ; measurement program. ..... vo... 00.288 0 HPIB er 86788 - | self test... 021444404444 4 44 en. ($,13,29 : user generated... va vii civic. 18 a oe AAA ль Ae wwe wpe ыы нтв ыы ue Mir — AT hp ARE wh iE A A ride A kr L rrent. 11440 4 4 4 0 0 0 80 0 4 80 4 0 4 00000 AA MS. LL 1 am 14 4 1 4 4 0 44 4 4 4 1 4 0 1 4 4 10 0 0 0 32 AY LL Le 1 1 a 0 44 ea 4 44 04 0 4 114051 5220 N JS LL LL La 0 40 4 44 4 04 0000 0 00000 RAS о 3SSAGES . ...'.rirrereecrcorerie. 13,28 rmal......ccroererrrevcerrr era. 12 | er generated messages. ......e.ercec.18 О | | | A Operating characteristics... 120000000007 A Po Operation mnemoniC. + «viv vei viv vrs cw 37 ronment | Optimizing reading rates... v7, ......18 à wironmental requirements. ............87 program for maximum rate. ..........—...B7 | gnal environments, ......_e.errecorvor.18 Output format,» UT rc 42 snded Ohms...........4.40<400.26,55 ; S, - armal Trigger... 12022010 a 1 В Р | Ш | Normal display. y 1.80 400000 ee ne ca eue 0 02 Programming Commäds. , ..............59 ' | Programming hints. ..................40,54 vk roa «+». 42 Mo +.” | КИ means НИ ду ам Была гр оо dat ae 28 a DEE 1 Bent. UU ee Qualifier. ooo riveree... 37 à 95 + Em. INDEX (Cont'd) Page В Range (ranging)... .... Key ....rcororeaciecerqarerrera as 420 Reading rate. ......ecereecororesverecoar 8 program for maximum rate... .eeccerao 07 Rear panel... 24044 00 4 44 4 4 6 00 10 0 88 switches. ......e.coccarorsoacrecir. 2508 REMOTE 142420000400 400 04 a 00 4 100 0 REQUIRE SERVICE (SRO)........... .46,86,80 Repair Service, . 044200000010 13 Resistance measurements. .....e _re.enr..28 wire. 26 A-Wite..... eoeearcoererranecerracc:. 20 extended ohms. «ooo civ erie ay. . 28 5 Safety considerations. .. oc vv verve... BB SENSE ‘terminais. 1.120046 4000 1 500 0 110$ SERIAL POLL (SPOLL). ........e....640-49,50 EEE. Signal environment. . ...c_.soeocoecesresose ÀB Single trigger... ......receceirereii: , 0. La 1 44444 0 67,18-82 Specifications... SRO 11114 4 1 0 414 4 0 8 1 44 8444000000 0 4,06 KEY HA MOSK LL. 10 4 1e 8 4 4 4 0 0 44 0 0 0 0 10 00 0 10 8 Status byte.........40 2040... 471 58,87,90 Status register... 04044405 4 401 4004 0081 No tT Aa , ‘ 2 r A ы dn № MBR E - A aaa e 4 1 444 10 À 00, . 45,86,89 Page т Temperature measurement program. ........54 TESHreSet. «vc heres irae. 4,28 Trigger 2.000000 0r 0070000000000 30,53,86,89 external 1... 142444 4 4 0 40 4 6 04 4 4 4 00 4 60 ST indicator... 24440445 400 0 1 ace 0 000 8Q internal. ......eeerervecicorredrrer.. 30 modes .....eeececseoreerecverracr: SO single. .... ..9ds carecer e rear. e Trouble, in case of... 4444440 dou 40 0 .B8 TURNING IT ON 221202 14 0 0 4 04 6 du 0 ona Two-wire ohms measuremente.........”r..26 LU User generated messages. .............. .15 \ Verification program........0444 4040 70,14 Voltage measurements. . a... AZ a 4 + * a 1 * + 4 E Voltmeter. complete... vo... loi. 34 : 1 W Warranty. 0.000000 rennen + 72 ir mer mh min mp Ai Sel WR mlm a sie AEF BT WR AAA МНО ЛМ hem shhh mE A dl A whet dll AEE RE eee mi ala AE Ml dell FE TW TE 4 ll es ET EEE CEE A EE ir ts Alla ies ij bbs ты lr ba AA di = - J E a LE FE € ! FE В x К - Talk-only mode... 11e. ua rence nee 425

Hewlett-Packard 3478A multimeter Operator's manual

Assistant Bot

Key Features

Frequently Answers and Questions

What is the purpose of the 3478A Multimeter?

What is the resolution of the 3478A Multimeter?

What types of measurements can the 3478A Multimeter perform?

How does the 3478A Multimeter handle autoranging?

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Hewlett-Packard 3478A multimeter Operator's manual

Assistant Bot

Key Features

Frequently Answers and Questions

What is the purpose of the 3478A Multimeter?

What is the resolution of the 3478A Multimeter?

What types of measurements can the 3478A Multimeter perform?

How does the 3478A Multimeter handle autoranging?

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