Agilent 34401A User's Guide

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User’s Guide

Part Number 34401-90004 February 1996

For Safety information, Warranties, and Regulatory information, see the pages behind the Index.

HP 34401A Multimeter

Note: Unless otherwise indicated, this manual applies to all Serial Numbers.

The HP 34401A is a 6

⁄

-digit, high-performance digital multimeter.

Its combination of bench-top and system features makes this multimeter a versatile solution for your measurement needs now and in the future.

Convenient Bench-Top Features

• Highly visible vacuum-fluorescent display

• Built-in math operations

• Continuity and diode test functions

• Hands-free, Reading Hold feature

• Portable, ruggedized case with non-skid feet

Flexible System Features

• HP-IB (IEEE-488) interface and RS-232 interface

• Standard programming languages: SCPI, HP 3478A, and Fluke 8840

• Reading rates up to 1000 readings per second

• Storage for up to 512 readings

• Limit testing with pass/fail signals

• Optional HP 34812A BenchLink/Meter Software

for Microsoft

Windows

HP 34401A Multimeter

The Front Panel at a Glance

1 Measurement Function keys 2 Math Operation keys 3 Single Trigger / Autotrigger / Reading Hold key 4 Shift / Local key

5 Front / Rear Input Terminal Switch 6 Range / Number of Digits Displayed keys 7 Menu Operation keys

The Front-Panel Menu at a Glance

The menu is organized in a top-down tree structure with three levels.

A: MEASurement MENU

1: AC FILTER  2: CONTINUITY  3: INPUT R  4: RATIO FUNC  5: RESOLUTION

B: MATH MENU

1: MIN-MAX  2: NULL VALUE  3: dB REL  4: dBm REF R  5: LIMIT TEST  6: HIGH LIMIT  7: LOW LIMIT

C: TRIGger MENU

1: READ HOLD  2: TRIG DELAY  3: N SAMPLES

D: SYStem MENU

1: RDGS STORE  2: SAVED RDGS  3: ERROR  4: TEST  5: DISPLAY  6: BEEP  7: COMMA  8: REVISION

E: Input / Output MENU

1: HP-IB ADDR  2: INTERFACE  3: BAUD RATE  4: PARITY  5: LANGUAGE

F: CALibration MENU

1: SECURED  [ 1: UNSECURED ]  [ 2: CALIBRATE ]  3: CAL COUNT  4: MESSAGE

The commands enclosed in square brackets ( [ ] ) are “hidden” unless the multimeter

is UNSECURED for calibration.

Display Annunciators

Adrs Rmt Man Trig Hold Mem Ratio Math ERROR Rear Shift

Turns on during a measurement. Multimeter is addressed to listen or talk over the HP-IB interface. Multimeter is in remote mode (remote interface). Multimeter is using manual ranging (autorange is disabled). Multimeter is waiting for a single trigger or external trigger. Reading Hold is enabled. Turns on when reading memory is enabled. Multimeter is in dcv:dcv ratio function. A math operation is enabled (null, min-max, dB, dBm, or limit test). Hardware or remote interface command errors are detected. Rear input terminals are selected.

“Shift” key has been pressed.

Multimeter is in 4-wire ohms function. Multimeter is in continuity test function. Multimeter is in diode test function.

Press “Shift” again to turn off.

To review the display annunciators, hold down the Shift key as you turn on the multimeter.

The Rear Panel at a Glance

1 Chassis Ground 2 Power-Line Fuse-Holder Assembly 3 Power-Line Voltage Setting 4 Front and Rear Current Input Fuse

5 Voltmeter Complete Output Terminal 6 External Trigger Input Terminal 7 HP-IB (IEEE-488) Interface connector 8 RS-232 interface connector

Use the front-panel Input / Output Menu to:

• Select the HP-IB or RS-232 interface (see chapter 4).

• Set the HP-IB bus address (see chapter 4).

• Set the RS-232 baud rate and parity (see chapter 4).

In This Book

Quick Start Chapter 1 prepares the multimeter for use and helps you get familiar with a few of its front-panel features.

Front-Panel Menu Operation Chapter 2 introduces you to the

front-panel menu and describes some of the multimeter’s menu features.

Features and Functions Chapter 3 gives a detailed description of the multimeter’s capabilities and operation. You will find this chapter useful whether you are operating the multimeter from the front panel or over the remote interface.

Remote Interface Reference Chapter 4 contains reference information to help you program the multimeter over the remote interface.

Error Messages Chapter 5 lists the error messages that may appear as you are working with the multimeter. Each listing contains enough information to help you diagnose and solve the problem.

Application Programs Chapter 6 contains several remote interface application programs to help you develop programs for your measurement application.

Measurement Tutorial Chapter 7 discusses measurement considerations and techniques to help you obtain the best accuracies and reduce sources of measurement error.

Specifications Chapter 8 lists the multimeter’s specifications and describes how to interpret these specifications.

If you have questions relating to the operation of the HP 34401A, call 1-800-452-4844 in the United States, or contact your nearest Hewlett-Packard Sales Office.

If your HP 34401A fails within three years of purchase, HP will repair or replace it free of charge. Call 1-800-258-5165 (“Express Exchange”)

in the United States, or contact your nearest Hewlett-Packard Sales Office.

Chapter 1 Quick Start

To Prepare the Multimeter for Use 13 If the Multimeter Does Not Turn On 14 To Adjust the Carrying Handle 16 To Measure Voltage 17 To Measure Resistance 17 To Measure Current 18 To Measure Frequency (or Period) 18 To Test Continuity 19 To Check Diodes 19 To Select a Range 20 To Set the Resolution 21 Front-Panel Display Formats 22 To Rack Mount the Multimeter 23

Chapter 2 Front-Panel Menu Operation

Front-Panel Menu Reference 27 A Front-Panel Menu Tutorial 29 To Turn Off the Comma Separator 37 To Make Null (Relative) Measurements 38 To Store Minimum and Maximum Readings 39 To Make dB Measurements 40 To Make dBm Measurements 41 To Trigger the Multimeter 42 To Use Reading Hold 43 To Make dcv:dcv Ratio Measurements 44 To Use Reading Memory 46

Chapter 3 Features and Functions

Measurement Configuration

AC Signal Filter 51 Continuity Threshold Resistance 52 DC Input Resistance 53 Resolution 54 Integration Time 57 Front / Rear Input Terminal Switching 58 Autozero 59 Ranging 60

Contents

Chapter 3 Features and Functions (continued)

Math Operations

Min-Max Operation 64 Null (Relative) Operation 65 dB Measurements 67 dBm Measurements 68 Limit Testing 69

Triggering

Trigger Source Choices 73 The Wait-for-Trigger State 76 Halting a Measurement in Progress 76 Number of Samples 77 Number of Triggers 78 Trigger Delay 79 Automatic Trigger Delays 81 Reading Hold 82 Voltmeter Complete Terminal 83 External Trigger Terminal 83

System-Related Operations

Reading Memory 84 Error Conditions 85 Self-Test 86 Display Control 87 Beeper Control 88 Comma Separators 89 Firmware Revision Query 89 SCPI Language Version Query 90

Remote Interface Configuration

HP-IB Address 91 Remote Interface Selection 92 Baud Rate Selection (RS-232) 93 Parity Selection (RS-232) 93 Programming Language Selection 94

Calibration

Calibration Security 95 Calibration Count 98 Calibration Message 99

Operator Maintenance

To Replace the Power-Line Fuse 100 To Replace the Current Input Fuses 100 Power-On and Reset State 101

Contents

Chapter 4 Remote Interface Reference

Command Summary 105 Simplified Programming Overview 112 The MEASure? and CONFigure Commands 117 Measurement Configuration Commands 121 Math Operation Commands 124 Triggering 127 Triggering Commands 130 System-Related Commands 132 The SCPI Status Model 134 Status Reporting Commands 144 Calibration Commands 146 RS-232 Interface Configuration 148 RS-232 Interface Commands 153 An Introduction to the SCPI Language 154 Output Data Formats 159 Using Device Clear to Halt Measurements 160 TALK ONLY for Printers 160 To Set the HP-IB Address 161 To Select the Remote Interface 162 To Set the Baud Rate 163 To Set the Parity 164 To Select the Programming Language 165 Alternate Programming Language Compatibility 166 SCPI Compliance Information 168 IEEE-488 Compliance Information 169

Contents

Chapter 5 Error Messages

Execution Errors 173 Self-Test Errors 179 Calibration Errors 180

Chapter 6 Application Programs

Using MEASure? for a Single Measurement 185 Using CONFigure with a Math Operation 186 Using the Status Registers 188 RS-232 Operation Using QuickBASIC 192 RS-232 Operation Using Turbo C 193

Contents

Chapter 7 Measurement Tutorial

Thermal EMF Errors 199 Loading Errors (dc volts) 199 Leakage Current Errors 199 Rejecting Power-Line Noise Voltages 200 Common Mode Rejection (CMR) 201 Noise Caused by Magnetic Loops 201 Noise Caused by Ground Loops 202 Resistance Measurements 203 4-Wire Ohms Measurements 203 Removing Test Lead Resistance Errors 204 Power Dissipation Effects 204 Settling Time Effects 204 Errors in High Resistance Measurements 205 DC Current Measurement Errors 205 True RMS AC Measurements 206 Crest Factor Errors 207 Loading Errors (ac volts) 209 Measurements Below Full Scale 210 High-Voltage Self-Heating Errors 210 Temperature Coefficient and Overload Errors 210 Low-Level Measurement Errors 211 Common Mode Errors 212 AC Current Measurement Errors 212 Frequency and Period Measurement Errors 213 Making High-Speed DC and Resistance Measurements 213 Making High-Speed AC Measurements 214

Chapter 8 Specifications

DC Characteristics 216 AC Characteristics 218 Frequency and Period Characteristics 220 General Information 222 Product Dimensions 223 To Calculate Total Measurement Error 224 Interpreting Multimeter Specifications 226 Configuring for Highest Accuracy Measurements 229

Index 231

Declaration of Conformity 237

Quick Start

One of the first things you will want to do with your multimeter is to become acquainted with its front panel. We have written the exercises in this chapter to prepare the multimeter for use and help you get familiar with some of its front-panel operations.

The front panel has two rows of keys to select various functions and operations. Most keys have a shifted function printed in blue above the key. To perform a shifted function, press annunciator will turn on). Then, press the key that has the desired label above it. For example, to select the dc current function,

Shift DC V .

press

Shift (the Shift

If you accidentally press

Shift annunciator.

The rear cover of this book is a fold-out Quick Reference Guide. On this cover you will find a quick summary of various multimeter features.

Shift , just press it again to turn off the

Chapter 1 Quick Start

To Prepare the Multimeter for Use

The following steps help you verify that the multimeter is ready for use.

1 Check the list of supplied items.

Verify that you have received the following items with your multimeter. If anything is missing, contact your nearest Hewlett-Packard Sales Office.

One test lead kit.

One power cord.

This User’s Guide.

One Service Guide.

One folded Quick Reference card.

Certificate of Calibration.

2 Connect the power cord and turn on the multimeter.

The front-panel display will light up while the multimeter performs its power-on self-test. The multimeter powers up in the dc voltage function with autoranging enabled.

To review the power-on display with all annunciators turned on, hold down

3Perform a complete self-test.

The complete self-test performs a more extensive series of tests than those performed at power-on. Hold down Power switch to turn on the multimeter; hold down the key for more than 5 seconds. The self-test will begin when you release the key.

If the self-test is successful, “ not successful, “ on. See the Service Guide for instructions on returning the multimeter to Hewlett-Packard for service.

Shift as you turn on the multimeter.

FAIL” is displayed and the ERROR annunciator turns

HP-IB bus address is displayed. Notice that the

Shift as you press the

PASS” is displayed. If the self-test is

Chapter 1 Quick Start

If the Multimeter Does Not Turn On

Use the following steps to help solve problems you might encounter when turning on the multimeter. If you need more help, see the Service Guide for instructions on returning the multimeter to Hewlett-Packard for service.

1 Verify that there is ac power to the multimeter.

First, verify that the multimeter’s Power switch is in the “On” position. Also, make sure that the power cord is firmly plugged into the power module on the rear panel. You should also make sure that the power source you plugged the multimeter into is energized.

2 Verify the power-line voltage setting.

The line voltage is set to the proper value for your country when the multimeter is shipped from the factory. Change the voltage setting if it is not correct. The settings are: 100, 120, 220, or 240 Vac (for 230 Vac operation, use the 220 Vac setting).

See the next page if you need to change the line-voltage setting.

3 Verify that the power-line fuse is good.

The multimeter is shipped from the factory with a power-line fuse installed. If you determine that the fuse is faulty, replace it with one that has the same rating as indicated on the multimeter’s rear panel.

See the next page if you need to replace the power-line fuse.

To replace the 250 mAT fuse, order HP part number 2110-0817. To replace the 125 mAT fuse, order HP part number 2110-0894.

Chapter 1 Quick Start

If the Multimeter Does Not Turn On

1 Remove the power cord. Remove the

fuse-holder assembly from the rear panel.

3 Rotate the line-voltage selector until the

correct voltage appears in the window.

2 Remove the line-voltage selector from

the assembly.

See rear panel for proper fuse rating

HP Part Number: 2110-0817 (250 mAT) 2110-0894 (125 mAT)

4 Replace the fuse-holder assembly in the rear panel.

100, 120, 220 (230) or 240 Vac

Verify that the correct line voltage is selected and the power-line fuse is good.

Chapter 1 Quick Start

To Adjust the Carrying Handle

To adjust the position, grasp the handle by the sides and pull outward. Then, rotate the handle to the desired position.

Bench-top viewing positions Carrying position

Chapter 1 Quick Start

To Measure Voltage

Ranges: 100 mV, 1 V, 10 V, 100 V, 1000 V (750 Vac) Maximum resolution: 100 nV (on 100 mV range) AC technique: true

RMS, ac-coupled

To Measure Resistance

Ranges: 100 Ω, 1 kΩ, 10 kΩ, 100 kΩ, 1 MΩ, 10 MΩ, 100 MΩ Maximum resolution: 100 µΩ (on 100 ohm range)

Chapter 1 Quick Start

To Measure Current

Ranges: 10 mA (dc only), 100 mA (dc only), 1 A , 3 A Maximum resolution: 10 nA (on 10 mA range) AC technique: true

RMS, ac-coupled

To Measure Frequency (or Period)

Measurement band: 3 Hz to 300 kHz (0.33 sec to 3.3 µsec)

Input signal range: 100 mVac to 750 Vac Technique: reciprocal counting

Chapter 1 Quick Start

To Test Continuity

Test current source: 1 mA

Maximum resolution: 0.1 Ω (range is fixed at 1 kohm) Beeper threshold: 1 Ω to 1000 Ω (beeps below adjustable threshold)

To Check Diodes

Test current source: 1 mA

Maximum resolution: 100 µV (range is fixed at 1 Vdc) Beeper threshold: 0.3 volts ≤ V

measured

≤ 0.8 volts (not adjustable)

Chapter 1 Quick Start

To Select a Range

You can let the multimeter automatically select the range using autoranging or you can select a fixed range using manual ranging.

Selects a lower range and disables autoranging.

Selects a higher range and disables autoranging.

Toggles between autoranging and manual ranging.

• Autoranging is selected at power-on and after a remote interface reset.

• Autorange thresholds:

Man annunciator is on when manual range is enabled.

Down range at <10% of range Up range at >120% of range

• If the input signal is greater than the present range can measure,

the multimeter will give an overload indication (“

• For frequency and period measurements from the front panel,

OVLD”).

ranging applies to the signal’s input voltage, not its frequency.

• The range is fixed for continuity (1 kΩ range) and diode (1 Vdc range).

Ranging is local to the selected function. This means that you can select the ranging method (auto or manual) for each function independently. When manually ranging, the selected range is local to the function; the multimeter remembers the range when you switch between functions.

Chapter 1 Quick Start

To Set the Resolution

You can set the display resolution to 4

⁄

, 5

⁄

, or 6

⁄

digits either to

optimize measurement speed or noise rejection. In this book, the most

⁄

significant digit (leftmost on the display) is referred to as the “

” digit,

since it can only be a “0” or “1.”

Press the Shift key.

Selects 4

⁄2 digits.

Selects 51⁄2 digits.

Selects 61⁄2 digits (

most noise rejection

• The resolution is set to 5

⁄

digits at power-on and after a remote

interface reset.

• The resolution is fixed at 5

• You can also vary the number of digits displayed using the arrow keys

⁄

digits for continuity and diode tests.

(however, the integration time is not changed).

Fewer More Digits D igits

Resolution is local to the selected function. This means that you can select the resolution for each function independently. The multimeter remembers the resolution when you switch between functions.

5 digits

Chapter 1 Quick Start

Front-Panel Display Formats

– Negative sign or blank (positive)

H “

⁄2 ” digit (0 or 1)

-H.DDD,DDD EFFF

Front-panel display format.

10.216,5 VDC

D Numeric digits E Exponent ( m, k, M ) F Measurement units ( VDC, OHM, HZ, dB )

“1⁄2” digit

⁄

This is the 10 Vdc range, 5

digits are displayed.

-045.23 mVDC

⁄

This is the 100 mVdc range, 4

digits are displayed.

113.325,6 OHM

⁄

This is the 100 ohm range, 6

digits are displayed.

OVL.D mVDC

This is an overload indication on the 100 mVdc range.

Chapter 1 Quick Start

To Rack Mount the Multimeter

You can mount the multimeter in a standard 19-inch rack cabinet using one of three optional kits available. Instructions and mounting hardware are included with each rack-mounting kit. Any of the same size can be rack-mounted beside the HP 34401A.

Remove the carrying handle, and the front and rear rubber bumpers, before rack-mounting the multimeter.

HP System II instrument

To remove the handle, rotate it to the vertical position and pull the ends outward.

Front

To remove the rubber bumper, stretch a corner and then slide it off.

Rear (bottom view)

Chapter 1 Quick Start

To Rack Mount the Multimeter

To rack mount a single instrument, order adapter kit 5063-9240.

To rack mount two instruments side-by-side, order lock-link kit 5061-9694 and flange kit 5063-9212.

To install one or two instruments in a sliding support shelf, order shelf 5063-9255, and slide kit 149 4-0015 ( for a sing le instr ument , also orde r filler panel 50 02-3999 ).

Front-Panel Menu Operation

By now you should be familiar with the FUNCTION and RANGE / DIGITS groups of front-panel keys. You should also understand how to make front-panel connections for the various types of measurements. If you are not familiar with this information, we recommend that you read

chapter 1, “Quick Start,” starting on page 11.

This chapter introduces you to three new groups of front-panel keys:

MENU, MATH, and TRIG. You will also learn how to use the comma

separator and store readings in memory. This chapter does not give a detailed description of every front-panel key or menu operation. It does, however, give you a good overview of the front-panel menu and many front-panel operations. See chapter 3 “Features and Functions,” starting on page 49, for a complete discussion of the multimeter’s capabilities and operation.

Chapter 2 Front-Panel Menu Operation

Front-Panel Menu Reference

A: MEASurement MENU

1: AC FILTER  2: CONTINUITY  3: INPUT R  4: RATIO FUNC  5: RESOLUTION

1: AC FILTER 2: CONTINUITY 3: INPUT R 4: RATIO FUNC 5: RESOLUTION

Selects the slow, medium, or fast ac filter. Sets the continuity beeper threshold (1 Ω to 1000 Ω). Sets the input resistance for dc voltage measurements. Enables the dcv:dcv ratio function. Selects the measurement resolution.

B: MATH MENU

1: MIN-MAX  2: NULL VALUE  3: dB REL  4: dBm REF R  5: LIMIT TEST  6: HIGH LIMIT  7: LOW LIMIT

1: MIN-MAX 2: NULL VALUE 3: dB REL 4: dBm REF R 5: LIMIT TEST 6: HIGH LIMIT 7: LOW LIMIT

Recalls the stored minimum, maximum, average, and reading count. Recalls or sets the null value stored in the null register. Recalls or sets the dBm value stored in the dB relative register. Selects the dBm reference resistance value. Enables or disables limit testing. Sets the upper limit for limit testing. Sets the lower limit for limit testing.

C: TRIGger MENU

1: READ HOLD  2: TRIG DELAY  3: N SAMPLES

1: READ HOLD 2: TRIG DELAY 3: N SAMPLES

Sets the reading hold sensitivity band. Specifies a time interval which is inserted before a measurement. Sets the number of samples per trigger.

Chapter 2 Front-Panel Menu Operation

Front-Panel Menu Reference

D: SYStem MENU

1: RDGS STORE  2: SAVED RDGS  3: ERROR  4: TEST  5: DISPLAY  6: BEEP  7: COMMA  8: REVISION

1: RDGS STORE 2: SAVED RDGS 3: ERROR 4: TEST 5: DISPLAY 6: BEEP 7: COMMA 8: REVISION

Enables or disables reading memory. Recalls readings stored in memory (up to 512 readings). Retrieves errors from the error queue (up to 20 errors). Performs a complete self-test. Enables or disables the front-panel display. Enables or disables the beeper function. Enables or disables a comma separator between digits on the display.

Displays the multimeter’s firmware revision codes.

E: Input / Output MENU

1: HP-IB ADDR  2: INTERFACE  3: BAUD RATE  4: PARITY  5: LANGUAGE

1: HP-IB ADDR 2: INTERFACE 3: BAUD RATE 4: PARITY 5: LANGUAGE

F: CALibration MENU

1: SECURED  [ 1: UNSECURED ]  [ 2: CALIBRATE ]  3: CAL COUNT  4: MESSAGE

1: SECURED 1: UNSECURED 2: CALIBRATE 3: CAL COUNT 4: MESSAGE

Sets the HP-IB bus address (0 to 31). Selects the HP-IB or RS-232 interface. Selects the baud rate for RS-232 operation. Selects even, odd, or no parity for RS-232 operation. Selects the interface language: SCPI, HP 3478, or Fluke 8840/42.

The multimeter is secured against calibration; enter code to unsecure. The multimeter is unsecured for calibration; enter code to secure. Performs complete calibration of present function; must be UNSECURED. Reads the total number of times the multimeter has been calibrated. Reads the calibration string (up to 12 characters) entered from remote.

The commands enclosed in square brackets ( [ ] ) are “hidden” unless the multimeter is UNSECURED for calibration.

Chapter 2 Front-Panel Menu Operation

A Front-Panel Menu Tutorial

This section is a step-by-step tutorial which shows how to use the front-panel menu. We recommend that you spend a few minutes with this tutorial to get comfortable with the structure and operation of the menu.

The menu is organized in a top-down tree structure with three levels (menus, commands, and parameters). You move down or up

∧ the menu tree to get from one level to the next. Each of the

three levels has several horizontal choices which you can view by moving left

< or right > .

Menus

Commands

∨

Parameters

• To turn on the menu, press Shift Menu On/Off .

• To turn off the menu, press Shift Menu On/Off , or press any of

the function or math keys on the top row of front-panel keys.

• To execute a menu command, press Enter .

• To recall the last menu command that was executed,

Shift Recall .

press

Chapter 2 Front-Panel Menu Operation

A Front-Panel Menu Tutorial

MESSAGES DISPLAYED DURING MENU USE

TOP OF MENU You pressed while on the “menus” level; this is the top level of the

menu and you cannot go any higher. To turn off the menu, press (Menu On/Off). To move across the choices

on a level, press or . To move down a level, press .

MENUS You are on the “menus” level. Press or to view the choices. COMMANDS You are on the “commands” level. Press or to view the

command choices within the selected menu group.

PARAMETER You are on the “parameter” level. Press or to view and edit

the parameter for the selected command.

MENU BOTTOM You pressed while on the “parameter” level; this is the bottom

level of the menu and you cannot go any lower. To turn off the menu, press (Menu On/Off). To move up a level,

press .

∧

CHANGE SAVED The change made on the “parameter” level is saved. This is

displayed after you press (Menu Enter) to execute the command.

MIN VALUE The value you specified on the “parameter” level is too small for the

selected command. The minimum value allowed is displayed for you to edit.

MAX VALUE The value you specified on the “parameter” level is too large for the

selected command. The maximum value allowed is displayed for you to edit.

EXITING MENU You will see this message if you turn off the menu by pressing

(Menu On/Off) or a front-panel function/math key. You did not edit any values

Shift

on the “parameter” level and changes were NOT saved.

∧

Shift

∨

Shift

Auto/Man

∨

NOT ENTERED You will see this message if you turn off the menu by pressing

(Menu On/Off) or a front-panel function/math key. You did some editing of

Shift parameters but the changes were NOT saved. Press (Menu Enter) to save changes made on the “parameter” level.

NOT RELEVANT The selected math operation is NOT valid for the function in use.

Auto/Man

Chapter 2 Front-Panel Menu Operation

A Front-Panel Menu Tutorial

Menu Example 1 The following steps show you how to turn on the menu, move up or

down between levels, move across the choices on each level, and turn off the menu. In this example, you will turn off the front-panel beeper.

On/Off

Shift <

> > >

∨

1 Turn on the menu.

You enter the menu on the “menus” level. The

MEAS MENU is your first

choice on this level.

A: MEAS MENU

2 Move across to the

SYS MENU choice on this level.

There are six menu group choices available on the “menus” level. Each choice has a letter prefix for easy identification (

A: , B: , etc.).

D: SYS MENU

3 Move down to the “commands” level within the

RDGS STORE command is your first choice on this level.

The

SYS MENU.

1: RDGS STORE

Chapter 2 Front-Panel Menu Operation

A Front-Panel Menu Tutorial

> > > > >

∨

4 Move across to the BEEP command on the “commands” level.

There are eight command choices available in the choice on this level has a number prefix for easy identification (

SYS MENU. Each

1: , 2: , etc.).

6: BEEP

5 Move down a level to the

The first parameter choice is “ setting is stored in non-volatile memory and “

BEEP parameter choices.

ON” for the BEEP command (the beeper

ON” is the factory setting).

6 Move across to the

There are two parameter choices for

“OFF” choice.

BEEP.

OFF

Auto/Man

ENTER

7 Save the change and turn off the menu.

The multimeter beeps and displays a message to show that the change is now in effect. You are then exited from the menu.

CHANGE SAVED

Chapter 2 Front-Panel Menu Operation

A Front-Panel Menu Tutorial

Menu Example 2 The following exercise demonstrates how to use the menu recall feature

as a shortcut to set the

BEEP command back to its original setting.

You must perform the steps in Example 1 before you start this example.

Shift

∨

Recall

1 Use menu recall to return to the

This returns you to the

BEEP command, which was the last command

BEEP command.

used before you exited the menu in the Example 1.

6: BEEP

2 Move down to the

The first parameter choice is “

BEEP parameter choices.

OFF” (the current setting from Example 1).

OFF

3 Move across to the

“ON” choice.

Set the parameter back to its original value.

Auto/Man

ENTER

4 Save the change and turn off the menu.

The multimeter beeps and displays a message to show that the change is now in effect. You are then exited from the menu.

CHANGE SAVED

Chapter 2 Front-Panel Menu Operation

A Front-Panel Menu Tutorial

Menu Example 3 Some commands in the menu require that you enter a numeric

parameter value. The following steps show you how to enter a number

in the menu. For this example, you will set the null value to –2.0 volts.

Make sure the multimeter is in the dc voltage function with 5

resolution displayed. Disconnect all inputs to the multimeter.

On/Off

Shift <

1 Turn on the menu.

⁄

digits of

∨

You enter the menu on the “menus” level. The

MEAS MENU is your first

choice on this level.

A: MEAS MENU

2 Move across to the

MATH MENU choice on this level.

There are six menu group choices available on this level.

B: MATH MENU

3 Move down to the “commands” level within the

MIN–MAX command is your first choice on this level.

The

1: MIN-MAX

4 Move across to the

NULL VALUE command on this level.

MATH MENU.

There are seven command choices available within the

2: NULL VALUE

MATH MENU.

Chapter 2 Front-Panel Menu Operation

A Front-Panel Menu Tutorial

∨

∨ ∨

5 Move down to edit the NULL VALUE parameter.

The null value should be 0.0 Vdc when you come to this point in the menu for the first time. For this example, you will set the null value

to –2.0 volts.

∧000.000 mVDC

When you see the flashing “∧” on the left side of the display, you can

abort the edit and return to the “commands” level by pressing

6 Make the number negative.

The leftmost character on the display toggles between + and – .

-000.000 mVDC

7 Move the flashing cursor over to edit the first digit.

Notice that the leftmost digit is flashing.

∧ .

∧

-000.000 mVDC

8 Increment the first digit until “ 2 ” is displayed.

You decrement or increment each digit independently. Neighboring digits are not affected.

-200.000 mVDC

Chapter 2 Front-Panel Menu Operation

A Front-Panel Menu Tutorial

< <

∧

Auto/Man

ENTER

9 Move the flashing cursor over to the “units” location.

Notice that the units are flashing on the right side of the display.

-200.000 mVDC

10 Increase the displayed number by a factor of 10.

Notice that the position of the decimal point changes and the displayed number increases by a factor of 10.

-2.000,00 VDC

11 Save the change and turn off the menu.

The multimeter beeps and displays a message to show that the change is now in effect. You are then exited from the menu.

CHANGE SAVED

Keep in mind that math null is turned on and –2.0 volts is used as the null value for measurements. To clear the null value, press

Null .

This is the end of the front-panel menu tutorial. The remainder of the chapter discusses several of the most common front-panel operations.

Chapter 2 Front-Panel Menu Operation

To Turn Off the Comma Separator

The multimeter can display readings on the front panel with or without a comma separator. The following steps show how to disable the comma.

On/Off

Shift <

∨

08.241,53 VDC

With comma separator

(factory setting) Without comma separator

08.24153 VDC

1 Turn on the menu.

A: MEAS MENU

2 Move across to the

SYS MENU choice on the “menus” level.

D: SYS MENU

3 Move down a level and then across to the

COMMA command.

7: COMMA

4 Move down a level and then move across to the “

OFF” choice.

Auto/Man

ENTER

OFF

5 Save the change and turn off the menu.

The comma separator setting is stored in non-volatile memory, and does not change when power has been off or after a remote interface reset.

Chapter 2 Front-Panel Menu Operation

To Make Null (Relative) Measurements

Each null measurement, also called relative, is the difference between a stored null value and the input signal.

Result = reading – null value

To read / edit the null value, use the MATH menu.

Enables null operation; Press again to disable.

• You can make null measurements with any function except

Math annunciator is on when null operation is enabled.

continuity, diode, or ratio. The null operation is local to the selected function; when you change functions, null is disabled.

• To null the test lead resistance for more accurate two-wire ohms

measurements, short the ends of the test leads together and then

Null .

press

• The first reading taken after you press Null is stored as the null

value in the Null Register. Any previously stored value is replaced with the new value.

• After enabling null, you can edit the stored null value by

pressing

NULL VALUE” command in the MATH MENU (only if null is

“

Shift > (Menu Recall). This takes you to the

enabled). Go down to the “parameter” level, and then edit the displayed value.

• The null register is cleared when you change functions, turn null off,

turn off the power, or perform a remote interface reset.

Chapter 2 Front-Panel Menu Operation

To Store Minimum and Maximum Readings

You can store the minimum and maximum readings during a series of measurements. The following discussion shows how to read the minimum, maximum, average, and reading count.

To read the minimu m, max im um , av era ge , an d co un t, use the MATH menu.

Enables min-max operation; Press again to disable.

• You can use min-max with any function except continuity or diode test.

Math annunciator is on when min-max operation is enabled.

The min-max operation is local to the selected function; when you change functions, min-max is disabled.

•• After enabling min-max, you can read the stored minimum,

maximum, average, and count by pressing

This takes you to the “

MIN–MAX” command in the MATH MENU

Shift > (Menu Recall).

(only if min-max is enabled). Go down to the “parameter” level, and then read the values by pressing

• The stored values are cleared when you turn min-max off, turn off the

< or > .

power, or perform a remote interface reset.

• The average is of all readings taken since min-max was enabled (not

just the average of the stored minimum and maximum). The count is the total number of readings taken since min-max was enabled.

Chapter 2 Front-Panel Menu Operation

To Make dB Measurements

Each dB measurement is the difference between the input signal and a stored relative value, with both values converted to dBm.

dB = reading in dBm – relative value in dBm

To read / edit the dB relative value, use the MATH menu.

Enables dB operation; Press again to disable.

• Select DC V or AC V .

• The first reading taken after you enable dB measurements is

Math annunciator is on when dB operation is enable d.

converted to dBm and is stored as the relative value in the dB Relative Register. Any previously stored value is replaced with the new value.

• After enabling dB operations, you can edit the relative value by

pressing

command in the

Shift > (Menu Recall). This takes you to the “dB REL”

MATH MENU (only if dB is enabled). Go down to

the “parameter” level, and then edit the value displayed.

• The register is cleared when you change functions, turn dB off,

turn off the power, or perform a remote interface reset.

Chapter 2 Front-Panel Menu Operation

To Make dBm Measurements

The dBm operation calculates the power delivered to a resistance referenced to 1 milliwatt.

dBm = 10 × Log

( reading

/ reference resistance / 1 mW )

To read / edit the dBm reference resistance, use the MATH menu.

Enables dBm operation; Press again to disable.

• Select DC V or AC V .

• The factory setting for the reference resistance is 600 Ω. To select a

different value, press

operations. This takes you to the “

MATH MENU (only if dBm is enabled).

Shift > (Menu Recall) after enabling dBm

dBm REF R” command in the

Math annunciator is on when dBm operation is enabled.

Go down to the “parameter” level, and then select a value: 50, 75, 93, 110, 124, 125, 135, 150, 250, 300, 500, 600, 800, 900, 1000, 1200, or 8000 ohms.

• The reference resistance is stored in non-volatile memory, and does not

change when power has been off or after a remote interface reset.

Chapter 2 Front-Panel Menu Operation

To Trigger the Multimeter

You can trigger the multimeter from the front panel using single trigger or auto trigger.

Enables single trigger and triggers the mu ltimeter.

Toggles between auto trigger and reading hold.

• Auto triggering is enabled when you turn on the multimeter. Notice

that the * (sample) annunciator turns on during each measurement.

• Single triggering takes one reading each time you press Single

and then waits for the next trigger. Continue pressing this key to trigger the multimeter.

Using an External Trigger

The external trigger mode is also enabled by pressing . It is like the single trigger mode except that you apply a trigger pulse to the rear-panel Ext Trig terminal. The multimeter is triggered on the negative edge of a TTL pulse.

The front-panel key is disabled when in remote.

Single

(sample) annunciator is on

during each measurement.

Trig annunciator is on when the multimeter is waiting for single trigger (auto trigg er di sa bl ed ).

Single

Chapter 2 Front-Panel Menu Operation

To Use Reading Hold

The reading hold feature allows you to capture and hold a stable reading on the display. When a stable reading is detected, the multimeter emits a beep and holds the value on the display.

To adjust the reading hold sensitivity band, use the TRIG menu.

Toggles between auto trigger and reading hold.

• Reading hold has an adjustable sensitivity band to allow you to

Hold annunciator is on when reading hold is enabled.

select which readings are considered stable enough to be displayed. The band is expressed as a percent of reading on the selected range. The multimeter will capture and display a new value only after three consecutive readings are within the band.

• The default band is 0.10% of reading. After enabling reading hold,

you can choose a different band by pressing

Shift >

(Menu Recall). This takes you to the “READ HOLD” command in

TRIG MENU (only if reading hold is enabled).

the

Go down to the “parameter” level, and then select a value:

0.01%, 0.10%, 1.00%, or 10.00% of reading.

• The sensitivity band is stored in volatile memory; the multimeter

sets the band to 0.10% of reading when power has been off or after a remote interface reset.

Chapter 2 Front-Panel Menu Operation

To Make dcv:dcv Ratio Measurements

To calculate a ratio, the multimeter measures a dc reference voltage applied to the terminals.

To enable ratio measurem en ts , us e th e MEAS me nu .

Sense terminals and the voltage applied to the Input

Ratio =

dc signal voltage

dc reference voltage

Ratio annunciator is on when

• At the Sense terminals, the reference voltage measurement function

ratio measurements are enabled.

is always dc voltage and has a maximum measurable input of

±12 Vdc. Autoranging is automatically selected for reference voltage

measurements on the

• The Input LO and Sense LO terminals must have a common reference

and cannot have a voltage difference greater than

• The specified measurement range applies only to the signal connected

Input terminals. The signal on the Input terminals can be any

to the

Sense terminals.

±2 volts.

dc voltage up to 1000 volts.

On/Off

Shift <

∨

Chapter 2 Front-Panel Menu Operation

To Make dcv:dcv Ratio Measurements

The following steps show you how to select the ratio function using the front-panel menu.

1 Turn on the menu.

A: MEAS MENU

2 Move down a level and then across to the

RATIO FUNC command.

4: RATIO FUNC

∨

Auto/Man

ENTER

3 Move down to the “parameter” level.

For this command, there is only one choice on this level.

DCV:DCV

4 Select the ratio function and turn off the menu.

Notice that the

Ratio annunciator turns on.

CHANGE SAVED

To disable ratio measurements, select a different measurement function by pressing any front-panel function key.

Chapter 2 Front-Panel Menu Operation

To Use Reading Memory

The multimeter can store up to 512 readings in internal memory. The following steps demonstrate how to store readings and retrieve them.

1 Select the function.

Select any measurement function. You can also select Null, Min–Max, dB, dBm, or limit test. You can change the function at any time during reading memory.

Single

On/Off

Shift <

> > >

∨

2 Select the single trigger mode.

Notice that the

Trig annunciator turns on. When reading memory is

enabled, readings are stored when you trigger the multimeter.

For this example, single triggering is used to store readings. You can also use auto triggering or reading hold.

3 Turn on the menu.

A: MEAS MENU

4 Move across to the

SYS MENU choice on this level.

D: SYS MENU

5 Move down to a level to the

RDGS STORE command.

1: RDGS STORE

Chapter 2 Front-Panel Menu Operation

To Use Reading Memory

Auto/Man

ENTER

Single Single Single

Recall

Shift >

> ∨

6 Move down a level and then across to the “ON” choice.

7 Save the change and exit the menu.

Notice that the multimeter is ready to store readings. Up to 512 readings can be stored in first-in-first-out ( will turn off.

Readings are preserved until you re-enable reading memory at another time, turn off the power, or perform a remote interface reset.

8 Trigger the multimeter three times.

This stores three readings in memory.

9 Use menu recall to retrieve the stored readings.

This takes you to the “

Mem (memory) annunciator turns on to indicate that the

FIFO) order. When memory is full, the Mem annunciator

SAVED RDGS” command in the SYS MENU.

2: SAVED RDGS

Chapter 2 Front-Panel Menu Operation

To Use Reading Memory

∨

On/Off

Shift <

10 Move down a level to view the first stored reading.

Reading memory is automatically turned off when you go to the

“parameter” level in the menu.

The first reading displayed is the first reading that was stored (FIFO).

If no readings are stored in memory, “

EMPTY” is displayed. The stored

readings are displayed with their units ( µ, m, k, etc.) when appropriate.

For example:

Reading numb er

10.31607K: 1

Exponent

11 Move across to view the two remaining stored readings.

The readings are stored horizontally on the “parameter” level.

If you press

< when you get to the “parameter” level, you will see the

last reading and you will know how many readings were stored.

12 Turn off the menu.

EXITING MENU

Features and Functions

You will find that this chapter makes it easy to look up all the details about a particular feature of the multimeter. Whether you are operating the multimeter from the front panel or from the remote interface, this chapter will be useful. This chapter is divided into the following sections:

• Measurement Configuration, starting on page 51

• Math Operations, starting on page 63

• Triggering, starting on page 71

• System-Related Operations, starting on page 84

• Remote Interface Configuration, starting on page 91

• Calibration Overview, starting on page 95

• Operator Maintenance, starting on page 100

• Power-On and Reset State, on page 101

Some knowledge of the front-panel menu will be helpful before you read

this chapter. If you have not already read chapter 2, “Front-Panel Menu Operation,” starting on page 25, you may want to read it now. Chapter 4, “Remote Interface Reference,” starting on page 103, lists the syntax for

SCPI commands available to program the multimeter.

the

Throughout this manual, the following conventions are used for

SCPI command syntax for remote interface programming.

• Square brackets ( [ ] ) indicate optional keywords or parameters.

• Braces ( { } ) enclose parameters within a command string.

• Triangle brackets ( < > ) indicate that you must substitute a value

for the enclosed parameter.

• A vertical bar (

) separates multiple parameter choices.

Chapter 3 Features and Functions

Measurement Configuration

This section contains information to help you configure the multimeter for making measurements. You may never have to change any of the measurement parameters discussed here, but they are provided to give you the flexibility you might need.

AC Signal Filter

The multimeter uses three different ac filters which enable you to either optimize low frequency accuracy or achieve faster ac settling times. The multimeter selects the slow, medium, or fast filter based on the input frequency that you specify.

Applies to ac voltage and ac current measurements only.

Input Frequency

3 Hz to 300 kHz 20 Hz to 300 kHz 200 Hz to 300 kHz

• The ac filter selection is stored in volatile memory; the multimeter

AC Filter Selected

Slow filter Medium filter (default) Fast filter

Settling Time

7 seconds / reading 1 reading / second 10 readings / second

selects the medium filter (20 Hz) when power has been off or after a remote interface reset.

• Front-Panel Operation: Select from the menu the slow filter (3 Hz),

medium filter (20 Hz), or fast filter (200 Hz). The default is the

medium filter.

1: AC FILTER (MEAS MENU)

• Remote Interface Operation: Specify the lowest frequency expected in

the input signal. The multimeter selects the appropriate filter based on the frequency you specify (see table above). The CONFigure and

MEASure? commands select the 20 Hz filter.

DETector:BANDwidth {3|20|200|MINimum|MAXimum}

Chapter 3 Features and Functions

Measurement Configuration

Continuity Threshold Resistance

When measuring continuity, the multimeter emits a continuous tone if the measured resistance is less than the threshold resistance. You can set the threshold to any value between 1

The threshold resistance is adjustable only from the front panel.

• The threshold resistance is stored in non-volatile memory, and does not

change when power has been off or after a remote interface reset.

• The factory setting for the threshold resistance is 10 Ω.

• After enabling the continuity function, you can select a different

threshold resistance by pressing

Ω and 1000 Ω.

Shift > (Menu Recall).

2: CONTINUITY (MEAS MENU)

See also “To Test Continuity,” on page 19.

∧0010 OHM

Chapter 3 Features and Functions

Measurement Configuration

DC Input Resistance

Normally, the multimeter’s input resistance is fixed at 10 MΩ for all dc voltage ranges to minimize noise pickup. To reduce the effects of measurement loading errors, you can set the input resistance to greater than 10 G

Applies to dc voltage measurements and is disabled for all other functions.

Fixed Resistance ON Fixed Resistance OFF

• The input resistance setting is stored in volatile memory; the

multimeter selects 10 M has been off or after a remote interface reset.

Ω for the 100 mVdc, 1 Vdc, and 10 Vdc ranges.

Input Resistance Input Resistance 100mV, 1V, 10V ranges 100V, 1000V ranges

(default)

10 MΩ 10 MΩ > 10 GΩ 10 MΩ

Ω (for all dc voltage ranges) when power

• Front-Panel Operation: Select from the menu the 10 MΩ mode (fixed

resistance for all dc voltage ranges) or the >10 G

is 10 M

Ω.

Ω mode. The default

3: INPUT R (MEAS MENU)

• Remote Interface Operation: You can enable or disable the automatic

input resistance mode. With is fixed at 10 M is set to >10 G

Ω for all ranges. With AUTO ON, the input resistance

Ω for the three lowest dc voltage ranges. The CONFigure

and MEASure? commands automatically turn

AUTO OFF (default), the input resistance

AUTO OFF.

INPut:IMPedance:AUTO {OFF|ON}

Chapter 3 Features and Functions

Measurement Configuration

Resolution

Resolution is expressed in terms of number of digits the multimeter can measure or display. You can set the resolution to 4, 5, or 6 full digits,

plus a “ accuracy and improve noise rejection, select 6 measurement speed, select 4

Applies to all measurement functions. The resolution for the math operations (null, min-max, dB, dBm, limit test) is the same as the resolution for the measurement function in use.

The correspondence between the number of digits selected and the resulting integration time (in power line cycles) is shown below. The autozero mode is set indirectly when you set the resolution.

Integration Time

Integration time is the period during which the multimeter’s analog-todigital (A/D) converter samples the input signal for a measurement. Integration time affects the measurement resolution (for better resolution, use a longer integration time), and measurement speed (for faster measurements, use a shorter integration time).

Applies to all measurement functions except ac voltage, ac current, frequency, and period. The integration time for the math operations (null, min-max, dB, dBm, limit test) is the same as the integration time for the measurement function in use.

• Integration time is specified in number of power line cycles (NPLCs).

The choices are 0.02, 0.2, 1, 10, or 100 power line cycles. The default

is 10 PLCs.

• The integration time is stored in volatile memory; the multimeter

selects 10 PLCs when power has been off or after a remote interface reset.

• Only the integral number of power line cycles (1, 10, or 100 PLCs)

provide normal mode (line frequency noise) rejection.

• The only way to control the reading rate for ac measurements is by

setting a trigger delay (see page 79).

• The following table shows the relationship between integration time

and measurement resolution.

Integration Time

0.02 NPLC

0.2 NPLC 1 NPLC 10 NPLC 100 NPLC

Resolution

0.0001 x Full-Scale

0.00001 x Full-Scale

0.000003 x Full-Scale

0.000001 x Full-Scale

0.0000003 x Full-Scale

Chapter 3 Features and Functions

Measurement Configuration

Integration Time

(continued)

• Front-Panel Operation: Integration time is set indirectly when you

select the number of digits. See the table for resolution on page 54.

• Remote Interface Operation:

function>:NPLCycles {0.02|0.2|1|10|100|MINimum|MAXimum}

For frequency and period measurements, aperture time (or gate time)

⁄

is analogous to integration time. Specify 10 ms (4 (default; 5

⁄

digits), or 1 second (6

⁄

digits).

digits), 100 ms

FREQuency:APERture {0.01|0.1|1|MINimum|MAXimum} PERiod:APERture {0.01|0.1|1|MINimum|MAXimum}

Front / Rear Input Terminal Switching

Any measurement made using the front terminals can also be made using the input terminals on the rear panel. See “The Front Panel at

a Glance,” on page 2, for the location of the front / rear switch.

The input terminals can only be configured from the front panel. You cannot select the terminals from the remote interface, but you can query the present setting.

• The Rear annunciator turns on when you select the rear terminals.

• Remote Interface Operation: You can query the multimeter to

determine whether the front or rear input terminals are selected.

ROUTe:TERMinals? returns “

FRON” or “REAR”

Chapter 3 Features and Functions

Measurement Configuration

Autozero

When autozero is enabled (default), the multimeter internally disconnects the input signal following each measurement, and takes a zero reading. It then subtracts the zero reading from the preceding

reading. This prevents offset voltages present on the multimeter’s input circuitry from affecting measurement accuracy.

When autozero is disabled, the multimeter takes one zero reading and subtracts it from all subsequent measurements. It takes a new zero reading each time you change the function, range, or integration time.

Applies to dc voltage, dc current, and 2-wire ohms measurements only. Autozero is enabled when you select 4-wire ohms or ratio measurements.

• The autozero mode is stored in volatile memory; the multimeter

automatically enables autozero when power has been off or after a remote interface reset.

• Front-Panel Operation: The autozero mode is set indirectly when you

set the resolution.

Resolution Choices

Fast 4 Digit

* Slow 4 Digit

Fast 5 Digit

* Slow 5 Digit

* Fast 6 Digit

Slow 6 Digit

* These settings configure the multimeter just as if you had

pressed the corresponding “DIGITS” keys from the front panel.

• Remote Interface Operation: The OFF and ONCE parameters have a

(default)

similar effect. Autozero Autozero

ONCE issues an immediate zero measurement.

Integration Time

0.02 PLC 1 PLC

0.2 PLC 10 PLC

10 PLC 100 PLC

OFF does not issue a new zero measurement.

Autozero

Off On

On On

ZERO:AUTO {OFF|ONCE|ON}

Chapter 3 Features and Functions

Measurement Configuration

Autozero

(continued)

The following table shows the relationship between integration time and autozero settings from the remote interface and the corresponding front-panel settings.

From HP 34401A Specifications:

Remote Configuration

NPLC: 100 Autozero: On Digits Displayed: 6

⁄

NPLC: 100 Autozero: Off Digits Displayed: 6

⁄

NPLC: 10 Autozero: On Digits Displayed: 6

⁄

NPLC: 10 Autozero: Off Digits Displayed: 6

⁄

NPLC: 1 Autozero: On Digits Displayed: 5

⁄

NPLC: 1 Autozero: Off Digits Displayed: 5

⁄

NPLC: 0.2 Autozero: On Digits Displayed: 5

⁄

NPLC: 0.2 Autozero: Off Digits Displayed: 5

⁄

NPLC: 0.02 Autozero: On Digits Displayed: 4

⁄

NPLC: 0.02 Autozero: Off Digits Displayed: 4

⁄

Front-Panel Equivalent

Slow 6 digits

N/A

Fast 6 digits Slow 5 digits

N/A

Slow 4 digits

N/A

Fast 5 digits

N/A

Fast 4 digits

Digits Displayed

N/A

⁄

N/A

⁄

N/A

⁄

N/A

⁄

N/A

⁄

Readings/Sec

N/A

0.6

N/A

300

N/A

1000

See the HP 34401A specifications listed on page 217.

Chapter 3 Features and Functions

Measurement Configuration

Ranging

You can let the multimeter automatically select the range using autoranging or you can select a fixed range using manual ranging. Autoranging is convenient because the multimeter automatically selects the appropriate range for each measurement. However, you can use manual ranging for faster measurements since the multimeter does not have to determine which range to use for each measurement.

• The selected mode (auto or manual range) is stored in volatile

memory; the multimeter returns to autoranging when power has been off or after a remote interface reset.

• Autorange thresholds:

Down range at <10% of range Up range at >120% of range

• If the input signal is greater than the present range can measure, the

multimeter gives an overload indication: “ panel or “9.90000000E+37” from the remote interface.

• For frequency and period measurements, the multimeter uses one

“range” for all inputs between 3 Hz and 300 kHz. The multimeter determines an internal resolution based on a 3 Hz signal. If you query the range, the multimeter will respond with “3 Hz”. With no input signal applied, frequency and period measurements return “0”.

OVLD” from the front

• The range is fixed for continuity tests (1 kΩ range) and diode tests

(1 Vdc range with 1 mA current source output).

• For ratio measurements, the specified range applies to the signal

connected to the selected for reference voltage measurements on the

Input terminals. Autoranging is automatically

Sense terminals.

Chapter 3 Features and Functions

Measurement Configuration

Ranging

(continued)

• Front-Panel Operation: Use the front-panel RANGE keys to select

autoranging or manual ranging. For frequency and period

measurements from the front panel, ranging applies to the signal’s input voltage, not its frequency.

See also “To Select a Range,” on page 20.

• Remote Interface Operation: You can set the range using any of the

following commands.

CONFigure:< MEASure:<

function>:RANGe {<range>|MINimum|MAXimum}

function>:RANGe:AUTO {OFF|ON}

function> {<range>|MIN|MAX|DEF},{<resolution>|MIN|MAX|DEF}

function>? {<range>|MIN|MAX|DEF},{<resolution>|MIN|MAX|DEF}

Chapter 3 Features and Functions

Math Operations

There are five math operations available, only one of which can be enabled at a time. Each math operation performs a mathematical operation on each reading or stores data on a series of readings. The selected math operation remains in effect until you disable it, change functions, turn off the power, or perform a remote interface reset. The math operations use one or more internal registers. You can preset the values in some of the registers, while others hold the results of the math operation.

Null Min-Max dB dBm Limit

The following table shows the math/measurement function combinations

allowed. Each “

X” indicates an allowable combination. If you choose a

math operation that is not allowed with the present measurement function, math is turned off. If you select a valid math operation and then change to one that is invalid, a “Settings conflict” error is generated from the remote interface.

DC V

X X X X X

AC V

X X X X X

DC I

X X

AC I

X X

Ω

X X

Ω

X X

Freq

X X

Per

Cont Diode Ratio

X X

From the front panel, you enable a math operation by pressing the appropriate key. The exception is Limit Test which you enable using the

LIMIT TEST command in the MATH MENU.

From the remote interface, the math operations and registers are controlled using commands within the CALCulate command subsystem. First, select the math operation you want to use (the default function is null):

CALCulate:FUNCtion {NULL|DB|DBM|AVERage|LIMit}

Then, enable the selected math function by turning the math state on:

CALCulate:STATe ON

Chapter 3 Features and Functions

Math Operations

Min–Max Operation

The min-max operation stores the minimum and maximum readings during a series of measurements. The multimeter then calculates the average of all readings and records the number of readings taken since min-max was enabled.

Applies to all measurement functions, except continuity and diode.

• After you enable min-max, the first reading that the multimeter

takes is stored as both the minimum and maximum value. The minimum is replaced with any subsequent value that is less. The maximum is replaced with any subsequent value that is greater.

• The multimeter displays “MIN” or “MAX” and beeps (if the front-panel

beeper is enabled) whenever a new minimum or maximum is found. It is possible that the multimeter will beep even if the displayed reading does not change; this is because the multimeter’s internal resolution may be greater than the displayed resolution. See also

“Beeper Control,” on page 88.

• The minimum, maximum, average, and count are stored in volatile

memory; the multimeter clears the values when min-max is turned on, when power has been off, or after a remote interface reset.

• Front-Panel Operation: After enabling min-max, you can read the

stored minimum, maximum, average, and count by pressing

Shift > (Menu Recall). Turning on the menu does not disable

the min-max operation; the multimeter will resume taking measurements when you turn off the menu.

1: MIN-MAX (MATH MENU)

See also “To Store Minimum and Maximum Readings,” on page 39.

Chapter 3 Features and Functions

Math Operations

• Remote Interface Operation: You can use the following commands to

make min-max measurements.

CALCulate:FUNCtion AVERage CALCulate:STATe {OFF|ON} CALCulate:AVERage:MINimum? read the minimum value CALCulate:AVERage:MAXimum? read the maximum value CALCulate:AVERage:AVERage? read the average of all readings CALCulate:AVERage:COUNt? read the count

A new command is available starting with firmware Revision 2 which allows you to take readings using INITiate without storing them in internal memory. This command may be useful with the min-max operation since it allows you to determine the average of a series of readings without storing the individual values.

DATA:FEED RD G_ ST ORE, "" do not store readings DATA:FEED RDG_STORE, "CALCulate" store readings (default)

See page 126 for more information on using the DATA:FEED command.

Null (Relative) Operation

When making null measurements, also called relative, each reading is the difference between a stored null value and the input signal. One possible application is in making more accurate two-wire ohms measurements by nulling the test lead resistance.

Result = reading – null value

Applies to all measurement functions, except continuity, diode, and ratio.

• The null value is adjustable and you can set it to any value between

0 and ±120% of the highest range, for the present function.

• The null value is stored in volatile memory; the value is cleared

when power has been off, after a remote interface reset, or after a function change.

Chapter 3 Features and Functions

Math Operations

Null (Relative)

(continued)

• The null value is stored in the multimeter’s Null Register. There are

two ways you can specify the null value. First, you can enter a specific number into the register from the front-panel menu or from the remote interface. Any previously stored value is replaced with the new value. If you are operating the multimeter from the front panel,

entering a null value also turns on the null function.

The second way to enter the null value is to let the multimeter store the first reading in the register. After you enable null, the first

reading displayed will be zero (if you have not changed the value stored in the register). If you entered a number into the register, as

described in the paragraph above, the first reading does not overwrite the stored value.

• Front-Panel Operation: After enabling null, you can edit the stored

null value by pressing

Shift > (Menu Recall). Any previously

stored value is replaced with the new value. Turning on the menu does not disable the null operation; the multimeter will resume taking measurements when you turn off the menu.

2: NULL VALUE (MATH MENU)

See also “To Make Null (Relative) Measurements,” on page 38.

• Remote Interface Operation: You can use the following commands to

make null measurements. Math must be enabled before you can store

a value in the Null Register.

CALCulate:FUNCtion NULL CALCulate:STATe {OFF|ON} CALCulate:NULL:OFFSet {<

value>|MINimum|MAXimum}

The following program segment shows the proper order that you should execute the commands to enable null and set an offset value.

CALC:FUNC NULL CALC:STAT ON CALC:NULL:OFFS -2.0

Chapter 3 Features and Functions

Math Operations

dB Measurements

Each dB measurement is the difference between the input signal and a stored relative value, with both values converted to dBm.

dB = reading in dBm – relative value in dBm

Applies to dc voltage and ac voltage measurements only.

• The relative value is adjustable and you can set it to any value

between 0 dBm and ±200.00 dBm.

• The relative value is stored in volatile memory; the value is cleared

when power has been off, after a remote interface reset, or after a function change.

• The relative value is stored in the multimeter’s dB Relative Register.

There are two ways you can specify the relative value. First, you can enter a specific number into the register from the front-panel menu or from the remote interface. Any previously stored value is replaced with the new value. If you are operating the multimeter from the front

panel, entering a relative value also turns on the dB function.

The second way to enter the relative value is to let the multimeter take the first reading, convert it to dBm, and store that value in the register. Changing the dBm reference resistance (see page 68) does not change the stored relative value. After you enable dB, the first

reading taken will be 0 dB (if you have not changed the value stored in the register). If you entered a number into the register, as described in the paragraph above, the first reading does not overwrite the stored value.

• Front-Panel Operation: After enabling dB, you can edit the stored

relative value by pressing stored value is replaced with the new value. Turning on the menu does not disable the dB operation; the multimeter will resume taking measurements when you turn off the menu.

3: dB REL (MATH MENU)

Shift > (Menu Recall). Any previously

See also “To Make dB Measurements,” on page 40.

Chapter 3 Features and Functions

Math Operations

• Remote Interface Operation: You can use the following commands to

make dB measurements. Math must be enabled before you can store a

value to the Relative Register.

CALCulate:FUNCtion DB CALCulate:STATe {OFF|ON} CALCulate:DB:REFerence {<

value>|MINimum|MAXimum}

dBm Measurements

The dBm operation calculates the power delivered to a resistance referenced to 1 milliwatt.

dBm = 10 × Log

( reading2 / reference resistance / 1 mW )

Applies to dc voltage and ac voltage measurements only.

• You can choose from 17 different reference resistance values.

The factory setting for the reference resistance is 600

Ω.

The choices are: 50, 75, 93, 110, 124, 125, 135, 150, 250, 300, 500,

600, 800, 900, 1000, 1200, or 8000 ohms.

• The reference resistance is stored in non-volatile memory, and does not

change when power has been off or after a remote interface reset.

• Front-Panel Operation: After enabling dBm, you can select a new

reference resistance by pressing

Shift > (Menu Recall). Turning

on the menu does not disable the dBm operation; the multimeter will resume taking measurements when you turn off the menu.

4: dBm REF R (MATH MENU)

See also “To Make dBm Measurements,” on page 41.

• Remote Interface Operation: You can use the following commands to

make dBm measurements.

CALCulate:FUNCtion DBM CALCulate:STATe {OFF|ON} CALCulate:DBM:REFerence {<

value>|MINimum|MAXimum}

Chapter 3 Features and Functions

Math Operations

Limit Testing

The limit test operation enables you to perform pass/fail testing to upper and lower limits that you specify.

Applies to all measurement functions, except continuity and diode tests.

• You can set the upper and lower limits to any value between 0 and

±120% of the highest range, for the present function. The upper limit

selected should always be a more positive number than the lower

limit. The default upper and lower limits are both “0”.

• The upper and lower limits are stored in volatile memory; the

multimeter sets both limits to “0” when power has been off, after a

remote interface reset, or after a function change.

• You can configure the multimeter to generate a service request (SRQ)

on the first occurrence of a failed reading. See “The SCPI Status

Model,” starting on page 134 for more information.

• Front-Panel Operation: The multimeter displays “OK” for each

reading that is within the specified limits. It displays “

each reading that exceeds the upper or lower limit. The multimeter

beeps once (if the front-panel beeper is enabled) on the first

occurrence of a failed reading after a good reading. See also “Beeper

Control,” on page 88.

5: LIMIT TEST (MATH MENU) enable or disable limit test

6: HIGH LIMIT (MATH MENU) set the upper limit

7: LOW LIMIT (MATH MENU) set the lower limit

You can also turn off limit test by selecting a different math operation

from the front panel (only one math operation can be enabled at a time).

HI” or “LO” for

Chapter 3 Features and Functions

Math Operations

Limit Testing

(continued)

• Remote Interface Operation: You can use the following commands for

limit testing.

CALCulate:FUNCtion LIMit CALCulate:STATe {OFF|ON} CALCulate:LIMit:LOWer {< CALCulate:LIMit:UPPer {<

• There are two unused pins on the RS-232 interface connector which

value>|MINimum|MAXimum} value>|MINimum|MAXimum}

are available to indicate the pass/fail status of readings taken with limit testing. To configure these pins for limit testing, you must install two jumpers inside the multimeter. See the Service Guide for

more information.

A low-going pulse is output to pin 1 for each reading that is within the specified limits. A low-going pulse is output to pin 9 for each reading that exceeds the upper or lower limit.

5 V

0 V

Caution

Pin 1: Pass Output Pin 9: Fail Output

2 ms

minimum

Do not use the RS-232 interface if you have configured the multimeter to output pass/fail signals on pins 1 and 9. Internal components on the RS-232 interface circuitry may be damaged.

Chapter 3 Features and Functions

Triggering

The multimeter’s triggering system allows you to generate triggers either manually or automatically, take multiple readings per trigger, and insert a delay before each reading. Normally, the multimeter will take one reading each time it receives a trigger, but you can specify multiple readings (up to 50,000) per trigger.

You can trigger the multimeter from the front panel using a single trigger, an external trigger, or auto triggering. Single triggering takes one reading each time you press the triggering is like single triggering, but the multimeter waits for a pulse on the rear-panel Ext Trig (external trigger) terminal before taking a reading. Auto triggering takes continuous readings at the fastest rate possible for the present configuration. See also “To Trigger

the Multimeter,” on page 42.

Triggering the multimeter from the remote interface is a multi-step process that offers triggering flexibility.

Single key. External

• First, you must configure the multimeter for the measurement by

selecting the function, range, resolution, etc.

• Then, you must specify the source from which the multimeter will

accept the trigger. The multimeter will accept a software (bus) trigger

from the remote interface, a hardware trigger from the Ext Trig

terminal, or an immediate internal trigger.

• Then, you must make sure that the multimeter is ready to accept a

trigger from the specified trigger source (this is called the

wait-for-trigger state).

The diagram on the next page shows the multimeter’s triggering system.

Chapter 3 Features and Functions

Triggering

HP 34401A Triggering System

Initiate Triggering

MEASure? READ? INITiate

Trigger Source

TRIGger:SOURce IMMediate TRIGger:SOURce EXTernal TRIGger:SOURce BUS

Front-panel “Single” key

Idle State

Wait-for Trigger State

Trigger Delay

TRIGger:DELay

Sample ( Q ) Annunciator

Delay

Measurement Sample

Sample Count

≠ 1

Trigger Count ≠ 1

Chapter 3 Features and Functions

Triggering

Trigger Source Choices

You must specify the source from which the multimeter will accept a trigger. From the front panel, the multimeter will accept a single trigger, a hardware trigger from the Ext Trig terminal, or continuously take readings using auto trigger. At power-on, auto triggering is used. From the remote interface, the multimeter will accept a software (bus) trigger, a hardware trigger from the Ext Trig terminal, or an immediate internal trigger. The * (sample) annunciator turns on during each measurement.

• The trigger source is stored in volatile memory; the source is set to

auto trigger (front panel) or immediate (remote interface) when

power has been off or after a remote interface reset.

• To select the trigger source from the remote interface, use the

following command. The CONFigure and MEASure? commands

automatically set the trigger source to IMMediate.

TRIGger:SOURce {BUS|IMMediate|EXTernal}

Auto Triggering In the auto trigger mode (front panel only), the multimeter continuously takes readings at the fastest rate possible for the present configuration. This is the power-on trigger source for front-panel operation.

Single Triggering In the single trigger mode (front panel only), you can manually trigger the multimeter by pressing The multimeter takes one reading, or the specified number of readings (sample count), each time you press the key. The annunciator turns on when the multimeter is waiting for a trigger.

The front-panel

Single key is disabled when in remote.

Single .

Trig

Chapter 3 Features and Functions

Triggering

External Triggering In the external trigger mode, the multimeter will accept a hardware trigger applied to the Ext Trig terminal. The multimeter takes one reading, or the specified number of readings (sample count), each time Ext Trig receives a low-true pulse.

See also “External Trigger Terminal,” on page 83.

• The multimeter buffers one external trigger. This means that if the

multimeter is taking a reading and another external trigger occurs,

that trigger is accepted (a “Trigger ignored” error is not reported). After the reading in progress is complete, the stored trigger satisfies the trigger source and then the trigger is issued.

• Front-Panel Operation: The external trigger mode is like the single

trigger mode except that you apply the trigger to the Ext Trig terminal. Pressing

enables the external trigger mode. The

Single to enable the single trigger mode also

Trig annunciator turns on

when the multimeter is waiting for an external trigger.

The front-panel

• Remote Interface Operation:

Single key is disabled when in remote.

TRIGger:SOURce EXTernal

Chapter 3 Features and Functions

Triggering

Internal Triggering In the internal trigger mode (remote interface only), the trigger signal is always present. When you place the multimeter in the wait-for-trigger state, the trigger is issued immediately. This is the power-on trigger source for remote interface operation.

To select the internal trigger source, send the following command. The CONFigure and MEASure? commands automatically set the trigger source to IMMediate.

TRIGger:SOURce IMMediate

Software (Bus) Triggering The bus trigger mode is available only from the remote interface. This mode is similar to the single trigger mode from the front panel, but you trigger the multimeter by sending a bus trigger command.

• To select the bus trigger source, send the following command.

TRIGger:SOURce BUS

• To trigger the multimeter from the remote interface (HP-IB or RS-232),

send the *TRG (trigger) command. The *TRG command will not be

accepted unless the multimeter is in the wait-for-trigger state.

• You can also trigger the multimeter from the HP-IB interface by

sending the

IEEE-488 Group Execute Trigger (GET) message.

The multimeter must be in the wait-for-trigger state. The following

statement shows how to send a

TRIGGER 722

Group Execute Trigger

GET using HP BASIC.

Chapter 3 Features and Functions

Triggering

The Wait-for-Trigger State

After you have configured the multimeter and selected a trigger source, you must place the multimeter in the wait-for-trigger state. A trigger will not be accepted until the multimeter is in this state. If a trigger signal is present, and if multimeter is in the “wait-for-trigger” state,

the measurement sequence begins and readings are taken.

The “wait-for-trigger” state is a term used primarily for remote interface operation. From the front panel, the multimeter is always in the “wait-for- trigger” state and will accept triggers at any time, unless a measurement is already in progress.

You can place the multimeter in the “wait-for-trigger” state by executing any of the following commands from the remote interface.

MEASure? READ? INITiate

The multimeter requires approximately 20 ms of set-up time after you

send a command to change to the “wait-for-trigger” state. Any triggers that occur during this set-up time are ignored.

Halting a Measurement in Progress

You can send a device clear at any time to halt a measurement in

progress and place the multimeter in the “idle state.” The following statement shows how to send a device clear over the using HP BASIC.

CLEAR 722

A device clear does not affect the configuration of the triggering system. The trigger source, sample count, trigger delay, and number of triggers are not changed.

IEEE-488 Device Clear

HP-IB interface

Chapter 3 Features and Functions

Triggering

Number of Samples

Normally, the multimeter takes one reading (or sample) each time it receives a trigger from the selected trigger source (if the multimeter is in the wait-for-trigger state). You can, however, instruct the multimeter to take multiple readings for each trigger received.

• Number of samples: 1 to 50,000. The default is 1 sample per trigger.

• The selected number of samples is stored in volatile memory; the

multimeter sets the sample count to 1 when power has been off or

after a remote interface reset. The CONFigure and MEASure?

commands automatically set the sample count to 1.

• Front-Panel Operation:

3: N SAMPLES (TRIG MENU)

• Remote Interface Operation:

SAMPle:COUNt {<

value>|MINimum|MAXimum}

Chapter 3 Features and Functions

Triggering

Number of Triggers

Normally, the multimeter will accept only one trigger before returning

to the “idle” trigger state. You can, however, instruct the multimeter to accept multiple triggers.

This feature is available only from the remote interface. If you set the trigger count and then go to local (front panel), the multimeter ignores the trigger count setting; when you return to remote, the trigger count returns to the value you selected.

• Number of triggers: 1 to 50,000. The default is 1 trigger.

• The selected number of triggers is stored in volatile memory; the

multimeter sets the trigger count to 1 when power has been off or after a remote interface reset. The CONFigure and MEASure? commands automatically set the trigger count to 1.

• Remote Interface Operation:

TRIGger:COUNt {<

value>|MINimum|MAXimum|INFinite}

Chapter 3 Features and Functions

Triggering

Trigger Delay

You can insert a delay between the trigger signal and each sample that follows. This may be useful in applications where you want to allow the input to settle before taking a reading, or for pacing a burst of readings. If you do not specify a trigger delay, the multimeter automatically selects a delay for you.

• Delay range: 0 to 3600 seconds. The default trigger delay is

automatic; the delay is determined by function, range, integration time,

and ac filter setting (see also “Automatic Trigger Delays,” on page 81).

• The trigger delay is stored in volatile memory; the multimeter selects

an automatic trigger delay when power has been off or after a remote

interface reset. The CONFigure and MEASure? commands

automatically set the trigger delay to automatic.

• If you specify a delay other than automatic, that same delay is used

for all functions and ranges.

• If you have configured the multimeter to take more than one reading

per trigger (sample count > 1), the specified trigger delay is inserted

between the trigger and each reading.

• Front-Panel Operation: You can use an automatic trigger delay or

you can specify a delay in seconds.

2: TRIG DELAY (TRIG MENU)

If an automatic trigger delay is enabled, “

AUTO” is displayed

momentarily before the actual number of seconds is displayed.

--- AUTO ---

Chapter 3 Features and Functions

Triggering

Trigger Delay

(continued)

• Front-Panel Operation (continued)

To set the delay to 0 seconds, select the “parameter” level of the

DELAY

the right side of the display. Press

command. Move the flashing cursor to the “units” location on

∨ until ZERO DELAY is reached,

then press Menu Enter.

ZERO DELAY

To select the automatic trigger delay, select the “parameter” level

TRIG DELAY command. Move the flashing cursor to the

of the “units” location on the right side of the display. Press

AUTO DELAY is reached, then press Menu Enter.

∨ until

AUTO DELAY

• Remote Interface Operation:

You can use the following command to set the trigger delay.

TRIGger:DELay {<

seconds>|MINimum|MAXimum}

You can use the following command to set an automatic trigger delay.

TRIG

TRIGger:DELay:AUTO {OFF|ON}

Chapter 3 Features and Functions

Triggering

Automatic Trigger Delays

If you do not specify a trigger delay, the multimeter selects an automatic delay for you. The delay is determined by function, range, integration time, and ac filter setting.

• DC Voltage and DC Current (for all ranges):

Integration Time

NPLC ≥ 1 NPLC < 1

• Resistance (2-wire and 4-wire):

Range

100 Ω 1 kΩ 10 kΩ 100 kΩ 1 MΩ 10 MΩ 100 MΩ

• AC Voltage and AC Current (for all ranges):

Remote or single/external trigger

AC Filter

Slow Medium Fast

Trigger Delay

1.5 ms

1.0 ms

Trigger Delay (For NPLC

1.5 ms

≥ 1)

1.5 ms

1.5 ms 15 ms 100 ms 100 ms

Trigger Delay

7.0 sec

1.0 sec 600 ms

Range

100 Ω 1 kΩ 10 kΩ 100 kΩ 1 MΩ 10 MΩ 100 MΩ

Front panel with auto trigger ON

AC Filter

Slow Medium Fast

Trigger Delay (For NPLC < 1)

1.0 ms

1.0 ms 10 ms 100 ms 100 ms

Trigger Delay

1.5 sec 200 ms 100 ms

• Frequency and Period:

Remote or single/external trigger

Trigger Delay

1.0 sec

Front panel with auto trigger ON

Trigger Delay

0 sec

Chapter 3 Features and Functions

Triggering

Reading Hold

The reading hold feature allows you to capture and hold a stable reading on the front-panel display. This is especially useful in situations where you want to take a reading, remove the test probes, and have the reading remain on the display. When a stable reading is detected, the multimeter emits a beep (if the front-panel beeper is enabled) and holds the reading on the display. See also “Beeper Control,” on page 88.

The reading hold feature is available only from the front panel. If you go to remote when reading hold is enabled, the multimeter ignores it; when you return to local (front panel), reading hold is enabled again.

• Reading hold has an adjustable sensitivity band (adjustable only from

the front panel) to allow you to select which readings are considered stable enough to be displayed. The band is expressed as a percent of reading, on the selected range. The multimeter will capture and display a new value only after three consecutive readings are within the band.

Select one of these values: 0.01%, 0.10% (default), 1.00%, or 10.00% of reading. For example, assume that the 1.00% band is selected and a 5 volt signal is applied to the multimeter. If three consecutive readings are between 4.975 volts and 5.025 volts, the display will show a new reading.

• The sensitivity band is stored in volatile memory; the multimeter sets

the band to 0.10% when power has been off or after an interface reset.

• If the multimeter is in autorange when you enable reading hold,

it will autorange to the correct range. If the multimeter is in the manual range mode, the same fixed range will be used for reading hold.

• When reading hold is enabled, the input resistance is automatically

set to 10 M

Ω (AUTO OFF) for all dc voltage ranges. This helps to

minimize noise pickup when the test leads are open-circuit.

• For certain applications, it may be useful to use reading hold with

reading memory. See also “Reading Memory,” on page 84.

• Front-Panel Operation: After enabling reading hold, you can select a

different sensitivity band by pressing

Shift > (Menu Recall).

1: READ HOLD (TRIG MENU)

See also “To Use Reading Hold,” on page 43.

Chapter 3 Features and Functions

Triggering

Voltmeter Complete Terminal

The rear-panel VM Comp (voltmeter complete) terminal provides a low-true pulse after the completion of each measurement. Voltmeter complete and external trigger (see below) implement a standard hardware handshake sequence between measurement and switching devices.

5 V

Output

0 V

Approximately 2 µs

External Trigger Terminal

You can trigger the multimeter by applying a low-true pulse to the rear-panel Ext Trig (external trigger) terminal. To use this terminal from the remote interface, you must select the external trigger source (TRIGger:SOURce EXTernal).

Input

5 V

0 V

>1 µs

You can use a simple switch to generate an external trigger using the Ext Trig input as shown below.

Ext Trig

Chapter 3 Features and Functions

System-Related Operations

This section gives information on topics such as reading memory, errors, self-test, and front-panel display control. This information is not directly related to making measurements but is an important part of operating the multimeter.

Reading Memory

The multimeter can store up to 512 readings in internal memory. Readings are stored in first-in-first-out ( returned is the first reading stored. The reading memory feature is

available only from the front panel.

• You can use reading memory with all functions, math operations, and

also reading hold. After you have enabled reading memory, you can change the function. Be aware, however, that the function labels

VDC, OHM, etc.) are not stored with the reading.

(

FIFO) order. The first reading

• Readings taken while reading memory is enabled are stored in

volatile memory; the multimeter clears the stored readings when reading memory is turned on again, when power has been off, after a self-test, or after a remote interface reset.

• You can use reading memory with auto trigger, single trigger,

external trigger, and reading hold. If you configure the multimeter for multiple readings per trigger, the specified number of readings are stored in memory each time a trigger is received.

• Front-Panel Operation:

1: RDGS STORE (SYS MENU) store readings in memory 2: SAVED RDGS (SYS MENU) read the stored readings

Reading memory is automatically turned off when you go to the

“parameter” level in the menu to recall the readings. See also “To Use Reading Memory,” on page 46.

• Remote Interface Operation: The INITiate command uses reading

memory to store readings prior to a FETCh? command. You can query the number of stored readings in memory by sending the DATA:POINts? command from the remote interface.

Chapter 3 Features and Functions

System-Related Operations

Error Conditions

When the front-panel ERROR annunciator turns on, one or more command syntax or hardware errors have been detected. A record of up

to 20 errors is stored in the multimeter’s error queue. See chapter 5,

“Error Messages,” for a complete listing of the errors.

• Errors are retrieved in first-in-first-out (FIFO) order. The first

error returned is the first error that was stored. When you have

read all errors from the queue, the

The multimeter beeps once each time an error is generated.

ERROR annunciator turns off.

• If more than 20 errors have occurred, the last error stored in the

queue (the most recent error) is replaced with -350, “Too many errors”.

No additional errors are stored until you remove errors from the

queue. If no errors have occurred when you read the error queue,

the multimeter responds with +0, “No error”.

• The error queue is cleared when power has been off or after a *CLS

(clear status) command has been executed. The *RST (reset)

command does not clear the error queue.

• Front-Panel Operation:

3: ERROR (SYS MENU)

ERROR annunciator is on, press Shift < (Recall Menu) to

If the read the errors stored in the queue. The errors are listed

horizontally on the “parameter” level. All errors are cleared when you go to the “parameter” level and then turn off the menu.

ERR 1: -113

First error in queue

• Remote Interface Operation:

Error code

SYSTem:ERRor?

Reads one error from the error queue

Errors have the following format (the error string may contain

up to 80 characters):

-113,"Undefined header"

Chapter 3 Features and Functions

System-Related Operations

Self-Test

A power-on self-test occurs automatically when you turn on the multimeter. This limited test assures you that the multimeter is operational. This self-test does not perform the extensive set of analog tests that are included as part of the complete self-test described below.

A complete self-test runs a series of tests and takes approximately 15 seconds to execute. If all tests pass, you can have a high confidence that the multimeter is operational.

• The results of the complete self-test are stored in internal reading

memory (see page 84). Memory is cleared as the self-test stores this information. Other than clearing memory, the complete self-test does not alter the state of the multimeter.

• If the complete self-test is successful, “PASS” is displayed on the front

panel. If the self-test fails, “ annunciator turns on. See the Service Guide for instructions on returning the multimeter to Hewlett-Packard for service.

FAIL” is displayed and the ERROR

• Front-Panel Operation: You can perform some of the tests (complete

self-test) individually or you can perform all tests together at once.

4: TEST (SYS MENU)

Another way to perform the complete front-panel self-test is as follows: Hold down

Shift as you press the Power switch to turn on the

multimeter; hold down the key for more than 5 seconds. The self- test will begin when you release the key.

• Remote Interface Operation:

*TST?

Returns “0” if the self-test is successful, or “1” if it fails.

Chapter 3 Features and Functions

System-Related Operations

Display Control

To speed up your measurement rate, or for security reasons, you may want to turn off the front-panel display. From the remote interface, you can also display a 12-character message on the front panel.

• When the display is turned off, readings are not sent to the display

and all display annunciators except

Front-panel operation is otherwise unaffected by turning off the display.

• The display state is stored in volatile memory; the display is enabled

when power has been off or after a remote interface reset.

• You can display a message on the front panel by sending a

command from the remote interface. The multimeter can display up

to 12 characters of the message on the front panel; any additional

characters are truncated. Commas, periods, and semicolons share a

display space with the preceding character, and are not considered

individual characters. When a message is displayed, readings are not

sent to the display.

• Sending a message to the display from the remote interface overrides

the display state; this means that you can display a message even if

the display is turned off.

ERROR and Shift are disabled.

• Front-Panel Operation:

5: DISPLAY (SYS MENU)

The display always turns on for menu operation; this means that

even when the display is turned off, you can still operate the menu.

• Remote Interface Operation:

DISPlay {OFF|ON} disable/enable the display

DISPlay:TEXT <

quoted string> display the string enclosed in quotes

DISPlay:TEXT:CLEar clear the displayed message

The following command string shows how to display a message on the

front panel.

"DISP:TEXT ’HELLO’"

Chapter 3 Features and Functions

System-Related Operations

Beeper Control

Normally, the multimeter will emit a tone whenever certain conditions are met from the front panel. For example, the multimeter will beep when a stable reading is captured in reading hold. You may want to disable the front-panel beeper for certain applications.

• When you disable the beeper, the multimeter will not emit a tone when:

1) a new minimum or maximum is found in a min–max test.

2) a stable reading is captured in reading hold.

3) a limit is exceeded in a limit test.

4) a forward-biased diode is measured in the diode test function.

• Disabling the beeper has no effect on the tone generated when:

1) an error is generated.

2) the continuity threshold is exceeded.

3) you turn off the front-panel menu.

Turning off the beeper does not disable the key click generated when you press a front-panel key.

• The beeper state is stored in non-volatile memory, and does not

change when power has been off or after a remote interface reset. The beeper is enabled when the multimeter is shipped from the factory.

• Front-Panel Operation:

6: BEEP (SYS MENU)

• Remote Interface Operation:

SYSTem:BEEPer issue a single beep immediately SYSTem:BEEPer:STATe {OFF|ON} disable/enable beeper state

Chapter 3 Features and Functions

System-Related Operations

Comma Separators

The multimeter can display readings on the front panel with or without a comma separator. This feature is available only from the front panel.

08.241,53 VDC

With comma separator

• The display format is stored in non-volatile memory, and does not

(factory setting) Without comma separator

08.24153 VDC

change when power has been off or after a remote interface reset.

The comma separator is enabled when the multimeter is shipped

from the factory.

• Front-Panel Operation:

7: COMMA (SYS MENU)

See also “To Turn Off the Comma Separator,” on page 37.

Firmware Revision Query

The multimeter has three microprocessors for control of various internal systems. You can query the multimeter to determine which revision of firmware is installed for each microprocessor.

• The multimeter returns three numbers. The first number is the

firmware revision number for the measurement processor; the second

is for the input/output processor; and the third is for the front-panel

processor.

• Front-Panel Operation:

8: REVISION (SYS MENU)

• Remote Interface Operation:

*IDN? returns

“HEWLETT-PACKARD,34401A,0,XX-XX-XX”

REV XX-XX-XX

Be sure to dimension a string variable with at least 35 characters.

Chapter 3 Features and Functions

System-Related Operations

SCPI Language Version Query

The multimeter complies with the rules and regulations of the present version of You can determine the compliance by sending a command from the remote interface.

SCPI (Standard Commands for Programmable Instruments).

SCPI version with which the multimeter is in

You cannot query the

• The following command returns the SCPI version.

SCPI version from the front panel.

SYSTem:VERSion?

Returns a string in the form “YYYY.V” where the “Y’s” represent the year of the version, and the “V” represents a version number for that year (for example, 1991.0).

Chapter 3 Features and Functions

Remote Interface Configuration

This section gives information on configuring the remote interface.

For additional information, see chapter 4, “Remote Interface Reference,” starting on page 103.

HP-IB Address

Each device on the HP-IB (IEEE-488) interface must have a unique address. You can set the multimeter’s address to any value between 0 and 31. The address is set to “22” when the multimeter is shipped from the factory. The

The HP-IB address can be set only from the front-panel.

• The address is stored in non-volatile memory, and does not change

when power has been off or after a remote interface reset.

• You can set the address to “31” which is the talk only mode. In this

mode, the multimeter can output readings directly to a printer

without being addressed by a bus controller (over either

RS-232). For proper operation, make sure your printer is configured in

the listen always mode. Address 31 is not a valid address if you are

operating the multimeter from the

HP-IB address is displayed at power-on.

HP-IB or

HP-IB interface with a bus controller.

If you select the

RS-232 interface and then set the HP-IB address to the

talk only address (31), the multimeter will send readings over the

RS-232 interface when in the local mode.

• If you select the RS-232 interface and then set the HP-IB address to

the talk only address (31), the multimeter will send readings over the

RS-232 interface when in the local mode.

• Your HP-IB bus controller has its own address. Be sure to avoid using

the bus controller’s address for any instrument on the interface bus.

Hewlett-Packard controllers generally use address “21”.

• Front-Panel Operation:

1: HP-IB ADDR (I/O MENU)

Remote Interface Selection

The multimeter is shipped with both an HP-IB (IEEE-488) interface and an The the factory.

The remote interface can be set only from the front-panel.

• The interface selection is stored in non-volatile memory, and does not

• If you select the HP-IB interface, you must select a unique address for

• If you select the RS-232 interface, you must set the baud rate and

• If you select the RS-232 interface and then set the HP-IB address to

RS-232 interface. Only one interface can be enabled at a time.

HP-IB interface is selected when the multimeter is shipped from

change when power has been off or after a remote interface reset.

the multimeter. The

HP-IB address is displayed when you turn on the

multimeter.

parity for the multimeter. “

RS-232” is displayed when you turn on the

multimeter.

the talk only address (31), the multimeter will send readings over the

RS-232 interface when in the local mode.

• There are certain restrictions to be aware of when you are selecting

the remote interface (see also “Programming Language Selection,” on page 94). The only programming language supported on

SCPI Language HP 3478A Language Fluke 8840A Language

• Front-Panel Operation:

HP-IB / 488

X X X

RS-232

X Not allowed Not allowed

RS-232 is SCPI.

2: INTERFACE (I/O MENU)

See also “To Select the Remote Interface,” on page 162.

Chapter 3 Features and Functions

Remote Interface Configuration

Baud Rate Selection (RS-232)

You can select one of six baud rates for RS-232 operation. The rate is set to 9600 baud when the multimeter is shipped from the factory.

The baud rate can be set only from the front-panel.

• Select one of the following: 300, 600, 1200, 2400, 4800, or 9600 baud

(factory setting).

• The baud rate selection is stored in non-volatile memory, and does not

change when power has been off or after a remote interface reset.

• Front-Panel Operation:

3: BAUD RATE (I/O MENU)

See also “To Set the Baud Rate,” on page 163.

Parity Selection (RS-232)

You can select the parity for RS-232 operation. The multimeter is configured for even parity with 7 data bits when shipped from the factory.

The parity can be set only from the front-panel.

• Select one of the following: None (8 data bits), Even (7 data bits), or

Odd (7 data bits). When you set the parity, you are indirectly setting

the number of data bits.

• The parity selection is stored in non-volatile memory, and does not

change when power has been off or after a remote interface reset.

• Front-Panel Operation:

4: PARITY (I/O MENU)

See also “To Set the Parity,” on page 164.

Chapter 3 Features and Functions

Remote Interface Configuration

Programming Language Selection

You can select one of three languages to program the multimeter from the selected remote interface. The language is shipped from the factory.

• Select one of the following: SCPI, HP 3478A, or Fluke 8840A.

• The language selection is stored in non-volatile memory, and does not

change when power has been off or after a remote interface reset.

• There are certain restrictions to be aware of when you are selecting

the interface language (see also “Remote Interface Selection,” on page 92). The HP 3478A and Fluke 8840A/8842A languages are not supported on the

RS-232 interface.

SCPI when the multimeter is

SCPI Language HP 3478A Language Fluke 8840A Language

• Front-Panel Operation:

HP-IB / 488

X X

RS-232

X Not allowed Not allowed

5: LANGUAGE (I/O MENU)

See also “To Select the Programming Language,” on page 165.

• Remote Interface Operation:

L1 select SCPI language L2 select HP 3478A language L3 select Fluke 8840A language

Chapter 3 Features and Functions

Calibration Overview

This section gives a brief introduction to the calibration features of the multimeter. For a more detailed discussion of the calibration procedures, see chapter 4 in the Service Guide.

Calibration Security

This feature allows you to enter a security code to prevent accidental or unauthorized calibrations of the multimeter. When you first receive your multimeter, it is secured. Before you can calibrate the multimeter, you must unsecure it by entering the correct security code.

• The security code is set to “HP034401” when the multimeter is

shipped from the factory. The security code is stored in non-volatile

memory, and does not change when power has been off or after a

remote interface reset.

• To secure the multimeter from the remote interface, the security code

may contain up to 12 alphanumeric characters as shown below.

The first character must be a letter, but the remaining characters can

be letters or numbers. You do not have to use all 12 characters but

the first character must always be a letter.

A _ _ _ _ _ _ _ _ _ _ _

• To secure the multimeter from the remote interface so that it can be

unsecured from the front panel, use the eight-character format shown

below. The first two characters must be “HP” and the remaining

characters must be numbers. Only the last six characters are

recognized from the front panel, but all eight characters are required.

(To unsecure the multimeter from the front panel, omit the “HP” and

enter the remaining numbers as shown on the following pages.)

H P _ _ _ _ _ _ (8 characters)

If you forget your security code, you can disable the security feature by adding a jumper inside the multimeter, and then entering a new code. See the Service Guide for more information.

(12 characters)

Chapter 3 Features and Functions

Calibration Overview

Calibration Security

(continued)

To Unsecure for Calibration You can unsecure the multimeter for calibration either from the front panel or remote interface. The multimeter is secured when shipped from the factory, and the

security code is set to “

• Front-Panel Operation:

HP034401”.

1: SECURED (CAL MENU)

If the multimeter is secured, you will see the above command when you go into the in the menu, you will notice that the “

CAL MENU. (If you move across the “commands” level

2: CALIBRATE” command is

“hidden” if the multimeter is secured.) To unsecure the multimeter, select the “parameter” level of the

SECURED command, enter the

security code, then press Menu Enter.

∧000000 CODE

When you go to the “commands” level in the

CAL MENU again,

you will notice that the multimeter is unsecured. Notice also that the

2: CALIBRATE” command is no longer hidden and you can perform

“ a calibration.

1: UNSECURED

• Remote Interface Operation:

CALibration:SECure:STATe {OFF|ON},<

code>

To unsecure the multimeter, send the above command with the same code used to secure. For example,

"CAL:SEC:STAT OFF,HP034401"

Chapter 3 Features and Functions

Calibration Overview

To Secure Against Calibration You can secure the multimeter against calibration either from the front panel or remote interface. The multimeter is secured when shipped from the factory, and the

security code is set to “

HP034401”.

Make sure you have read the security code rules on page 95 before attempting to secure the multimeter.

• Front-Panel Operation:

1: UNSECURED (CAL MENU)

If the multimeter is unsecured, you will see the above command when

you go into the

“parameter” level of the

CAL MENU. To secure the multimeter, select the

UNSECURED command, enter the security

code, then press Menu Enter.

∧000000 CODE

When you go to the “commands” level in the

CAL MENU again,

you will notice that the multimeter is secured. Notice also that the

2: CALIBRATE” command is now hidden and you cannot perform

“

a calibration.

1: SECURED

• Remote Interface Operation:

CALibration:SECure:STATe {OFF|ON},<

code>

To secure the multimeter, send the above command with the same

code as used to unsecure. For example,

"CAL:SEC:STAT ON,HP034401"

Chapter 3 Features and Functions

Calibration Overview

Calibration Security

(continued)

To Change the Security Code To change the security code, you must first unsecure the multimeter, and then enter a new code. Make sure you have read the security code rules on page 95 before attempting to secure the multimeter.

• Front-Panel Operation: To change the security code, first make sure

that the multimeter is unsecured. Select the “parameter” level of the

UNSECURED command, enter the new security code, then press

Menu Enter. Changing the code from the front panel also changes the code as seen from the remote interface.

• Remote Interface Operation:

CALibration:SECure:CODE <

new code>

To change the security code, first unsecure the multimeter using the old security code. Then, enter the new code. For example,

CAL:SEC:STAT OFF, HP034401 unsecure with old code CAL:SEC:CODE ZZ010443 enter new code

Calibration Count

You can determine the number of times that your multimeter has been calibrated. Your multimeter was calibrated before it left the factory. When you receive your multimeter, read the count to determine its initial value.

• The calibration count is stored in non-volatile memory, and does not

change when power has been off or after a remote interface reset.

• The calibration count increments up to a maximum of 32,767 after

which it wraps-around to 0. Since the value increments by one for each calibration point, a complete calibration increases the value by several counts.

• Front-Panel Operation:

3: CAL COUNT (CAL MENU)

• Remote Interface Operation:

CALibration:COUNt?

Chapter 3 Features and Functions

Calibration Overview

Calibration Message

You can use the calibration message feature to record calibration information about your multimeter. For example, you can store such information as the last calibration date, the next calibration due date,

the multimeter’s serial number, or even the name and phone number of the person to contact for a new calibration.

You can record information in the calibration message only from the remote interface. However, you can read the message from either the front-panel menu or the remote interface.

• The calibration message may contain up to 40 characters. However,

the multimeter can display only 12 characters of the message on the

front panel (additional characters are truncated).

• The calibration message is stored in non-volatile memory, and

does not change when power has been off or after a remote

interface reset.

• Front-Panel Operation:

4: MESSAGE (CAL MENU) read the cal message

• Remote Interface Operation:

CALibration:STRing <

The following command string shows how to store a calibration message.

"CAL:STR ’CAL 2-1-96’"

quoted string> store the cal message

Agilent 34401A User's Guide

Specifications and Main Features

Frequently Asked Questions

User Manual

The Front Panel at a Glance

Display Annunciators

The Rear Panel at a Glance

In This Book

Contents

To Prepare the Multimeter for Use

If the Multimeter Does Not Turn On

To Adjust the Carrying Handle

To Measure Voltage

To Measure Resistance

To Measure Current

To Measure Frequency (or Period)

To Test Continuity

To Check Diodes

To Select a Range

To Set the Resolution

Front-Panel Display Formats

To Rack Mount the Multimeter

Front-Panel Menu Reference

A Front-Panel Menu Tutorial

MESSAGES DISPLAYED DURING MENU USE

Menu Example 1 The following steps show you how to turn on the menu, move up or

Menu Example 2 The following exercise demonstrates how to use the menu recall feature

Menu Example 3 Some commands in the menu require that you enter a numeric

To Turn Off the Comma Separator

To Make Null (Relative) Measurements

To Store Minimum and Maximum Readings

To Make dB Measurements

To Make dBm Measurements

To Trigger the Multimeter

To Use Reading Hold

To Make dcv:dcv Ratio Measurements

To Use Reading Memory

Measurement Configuration

AC Signal Filter

Continuity Threshold Resistance

DC Input Resistance

Resolution

Integration Time

Front / Rear Input Terminal Switching

Autozero

Ranging

Math Operations

Min–Max Operation

Null (Relative) Operation

dB Measurements

dBm Measurements

Limit Testing

Triggering

HP 34401A Triggering System

Trigger Source Choices

Auto Triggering In the auto trigger mode (front panel only), the multimeter continuously takes readings at the fastest rate possible for the present configuration. This is the power-on trigger source for front-panel operation.

External Triggering In the external trigger mode, the multimeter will accept a hardware trigger applied to the Ext Trig terminal. The multimeter takes one reading, or the specified number of readings (sample count), each time Ext Trig receives a low-true pulse.

Internal Triggering In the internal trigger mode (remote interface only), the trigger signal is always present. When you place the multimeter in the wait-for-trigger state, the trigger is issued immediately. This is the power-on trigger source for remote interface operation.

Software (Bus) Triggering The bus trigger mode is available only from the remote interface. This mode is similar to the single trigger mode from the front panel, but you trigger the multimeter by sending a bus trigger command.

The Wait-for-Trigger State

Halting a Measurement in Progress

Number of Samples

Number of Triggers

Trigger Delay

Automatic Trigger Delays

Reading Hold

Voltmeter Complete Terminal

External Trigger Terminal

System-Related Operations

Reading Memory

Error Conditions

Self-Test

Display Control

Beeper Control

Comma Separators

Firmware Revision Query

SCPI Language Version Query

Remote Interface Configuration

HP-IB Address

Remote Interface Selection