Agilent Technologies 34420A User manual

The34420A is a 71/2digit,high performancenanovolt,micro-ohm
meter. Its combination of bench-top and system features makes this
meter a versatile solution for your testing requirements now and in the
future.
Convenient bench-top features
•Built-in math operations including thermistor, thermocouple and
RTD temperature measurements
•Two channel input allows ratio and difference functions for voltage
measurements
•Highly visible vacuum-fluorescent display
•Portable, ruggedized case with non-skid feet
Flexible system features
•HP-IB (IEEE-488) interface and RS-232 interface are standard
•SCPI (Standard Commands for Programmable Instruments) and
Keithley 181 compatibility
•Readings at up to 250 per second
HP34420A
Nano Volt/Micro Ohm Meter
Agilent 34420A
GPIB

The Front-Panel at a Glance
1Input channel select 5Menu operation keys
2Measurement function keys 6Range/number of digits displayed keys
3Math operation keys 7Single trigger/autotrigger/auto hold key
4Filter select key 8Shift / local key
2

The Front-Panel Menu at a Glance
The menu is organized in a top-down tree structure with three levels.
A: MEASurement MENU
1: DIG FILTER Ø 2: INTEGRATE Ø 3: OCOMP Ω Ø 4: LOW POWER Ω Ø 5: LOW VOLT Ω Ø 6: LoV LIMIT Ω
B: TEMPerature MENU
1: PROBE TYPE Ø 2: UNITS Ø 3: RTD TYPE Ø 4:RTD Ro Ø 5: T/C TYPE Ø 6: COLD JUNCT Ø 7: JUNCT TEMP
C: MATH MENU
1: STATS Ø 2: NULL VALUE Ø 3: SCALE GAIN Ø 4: SCALE OFST
D: TRIGger MENU
1: READ HOLD Ø 2: TRIG DELAY Ø 3: N SAMPLES
E: SYStem MENU
1: RDGS STORE Ø 2: SAVED RDGS Ø 3: ERROR Ø 4: TEST Ø 5: CHART OUT Ø 6: CHART SPAN Ø
7: CHART NULL Ø 8: DISPLAY Ø 9: COMMA Ø 10: PRESET Ø 11: REVISION
F: Input/Output MENU
1: HP-IB ADDR Ø 2: INTERFACE Ø 3: BAUD RATE Ø 4: PARITY Ø 5: LANGUAGE
G: CALibration MENU
1: UNSECURED Ø [1: SECURED] Ø [2: CALIBRATE] Ø [3: CHART ZERO] Ø [4: CHART GAIN] Ø
[5: INJECTED I] Ø 6: CAL COUNT Ø 7: MESSAGE
NOTE: The commands enclosed in square brackets ([ ]) in the CAL MENU are "hidden" unless the meter is UNSECURED for calibration.
To turn on menu press:
To move left/right To move up/down
To enter a command press:
3

Display Annunciators
*Turns on during a measurement.
Adrs Meter is addressed to listen or talk over the HP-IB interface.
Rmt Meter is in remote mode (using remote interface).
Man Meter is using manual ranging (autorange is disabled).
Trig Meter is waiting for a single trigger or external trigger.
OC Off Offset compensation is turned off.
Null A null value is being used.
Stats Math statistics operations are being used.
Scale Math scaling operations are being used.
ERROR Hardware or remote interface command error(s) detected.
Shift "Shift" key has been pressed.
Ch1 Meter input is on Channel 1.
Ch2 Meter input is on Channel 2.
Ch1 - Ch2 Meter is indicating the difference between inputs on channel 1 and channel 2.
Ch1 / Ch2 Meter is indicating the ratio of the inputs on channel 1 and channel 2.
ΩMeter is measuring resistance (Ohms).
LP Meter is using low power Ohms.
2W Meter is using 2-wire Ohms (annunciator off indicates a 4-wire measurement).
LoV Meter is using voltage limited Ohms.
Hold Automatic reading hold is enabled.
Filt The analog and/or the digital filter is enabled.
Mem Turns on when reading memory is enabled.
To review the display annunciators, hold down the Shift key as you
turn on the meter.
4

The Rear Panel at a Glance
1Chassis ground 5Voltmeter complete output terminal
2Power-line fuse-holder assembly 6External trigger input terminal
3Power-line voltage setting7GPIB (IEEE-488) interface connector
4Chart recorder output terminal
(Analog out)
8RS-232 interface connector
Use the front-panel Input / Output Menu to:
•Select the GPIB or RS-232 interface
•Set the GPIB bus address
•Set the RS-232 baud rate and parity
5

In This Book
Quick Start Chapter 1 prepares the meter for use and helps you get
familiar with a few of its front-panel features.
Front-Panel Operation Chapter 2 introduces you to the front-panel menu
and describes some of the meter’s menu features.
Features and Functions Chapter 3 gives a detailed description of the
meter’s capabilities and operation. You will find this chapter useful
whether you are operating the meter from the front panel or from a
remote interface.
Remote Interface Reference Chapter 4 contains reference
information to help you program the meter using a remote interface.
Error Messages Chapter 5 lists the error messages that may appear as
you are working with the meter. 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 accuracy and
reduce sources of measurement error.
Specifications Chapter 8 lists the meter’s specifications and describes
how to interpret these specifications.
If you have questions relating to the operation of the meter, call
1-800-452-4844 in the United States, or contact your nearest
6
Agilent Technologies Sales Office.

Contents
Chapter 1 Quick Start
To Prepare the Meter For Use 13
If the Meter Does Not Turn On 14
To Adjust the Carrying Handle 16
To Make Input Connections 17
To Measure Voltage 19
To Measure Resistance 20
To Measure Temperature With Thermistors 21
To Measure Temperature With RTDs 21
To Measure Temperature With Thermocouples 22
To Select a Range 23
To Set the Number of Digits 24
To Set the Integration Time 25
Front-Panel Display Formats 26
To Rack Mount the Meter 27
Chapter 2 Front-Panel Operation
Front-Panel Menu Reference 31
A Front-Panel Menu Tutorial 33
To Select an Input Channel 41
To Select a Range 42
To Set or Change the Number of Digits 43
To Set the Integration Time 44
To Make Null (Relative) Measurements 45
To Store Minimum and Maximum Readings (Stats) 46
To Trigger the Meter 47
To Use Reading Hold 48
To Make Voltage Ratio and Difference Measurements 49
To Use Reading Memory 50
Chapter 3 Features and Functions
General Measurement Configuration 55
Input Filters 55
Integration Time 58
Reducing Measurement Noise 60
Number of Digits Displayed 62
Ranging 64
Overload Detection 65
Voltage Measurement Configuration 66
Input Channels 66
Resistance Measurement Configuration 68
Temperature Measurement Configuration 71
Measurement Units 71
RTD Measurements 72
Thermistor Measurements 72
Thermocouple Measurements 73
C
o
n
t
e
n
t
s
7

Chapter 3 Features and Functions (continued)
Math Operations 74
Null (Relative) Operation 77
Reading Hold 79
Triggering 80
Trigger Source Choices 82
The Wait-for-Trigger State 85
Halting a Measurement in Progress 85
Number of Samples 86
Number of Triggers 86
Trigger Delay 87
Automatic Trigger Delays 89
System-Related Operations 90
Reading Memory 90
Error Conditions 92
Self-Test 93
Display Control 94
Comma Separators 95
Firmware Revision Query 95
SCPI Language Version 96
Voltmeter Complete Terminal 97
External Trigger Terminal 97
Chart Output (Analog Output) 98
Chart Rollover 100
Remote Interface Configuration 101
Remote Interface Selection 101
HP-IB Address 102
Baud Rate Selection (RS-232) 103
Parity Selection (RS-232) 104
Programming Language Selection 105
Connection to a Terminal or Printer (RS-232) 106
Calibration 107
Calibration Security 107
Calibration Count 110
Calibration Message 111
Defaults, Power-On and Reset States 112
Chapter 4 Remote Interface Reference
Command Summary 117
Simplified Programming Sequence 126
Using the MEASure? Command 128
Using the CONFigure Command 128
Using the range and resolution Parameters 129
Using the READ? Command 130
Using the INITiate and FETCh? Commands 131
The MEASure? and CONFigure Commands 134
Setting the Function, Range, and Resolution 137
Selecting the Input Channel 140
Special Resistance Measurement Commands 141
Temperature Measurement Commands 142
Contents
8
GPIB