B&K Precision 2831E Instruction Manual

4 ½ Digit and 50,000 Count Bench

Model 2831E , 5491B

Multimeters

USER MANUAL

Notice

The information contained in this document is subject to change without notice.

Safety Notice Supplement

As described in the International Electrotechnical Commission (IEC) Standard IEC 664, digital multimeter measuring circuits (e.g., B&K Models 2831E and 5491B) and the USB terminal are Installation Category II (CATII). The AC input terminal is rated CAT I.

This equipment is POLLUTION DEGREE 2, INDOOR USE product.

Safety Summary

The following safety precautions apply to both operating and maintenance personnel and must be observed during all phases of operation, service, and repair of this instrument. Before applying power, follow the installation instructions and become familiar with the operating instructions for this instrument.

GROUND THE INSTRUMENT

To minimize shock hazard, the instrument chassis and cabinet must be connected to an electrical ground. This instrument is grounded through the ground conductor of the supplied, three-conductor ac power cable. The power cable must be plugged into an approved three-conductor electrical outlet. Do not alter the ground connection. Without the protective ground connection, all accessible conductive parts (including control knobs) can render an electric shock. The power jack and mating plug of the power cable meet IEC safety standards.

DO NOT OPERATE IN AN EXPLOSIVE ATMOSPHERE

Do not operate the instrument in the presence of flammable gases or fumes. Operation of any electrical instrument in such an environment constitutes a definite safety hazard.

KEEP AWAY FROM LIVE CIRCUITS

Instrument covers must not be removed by operating personnel. Component replacement and internal adjustments must be made by qualified maintenance personnel. Disconnect the power cord before removing the instrument covers and replacing components. Under certain

conditions, even with the power cable removed, dangerous voltages may exist. To avoid

accessible conductive parts (including control knobs) can render an electric shock.

To avoid electrical shock hazard, disconnect power cord before removing covers.

Before connecting the line cord to the AC mains, check the rear panel AC line

lying a line voltage other than the indicated voltage can

destroy the AC line fuses. For continued fire protection, replace fuses only with

static discharge

sensitive

injuries, always disconnect power and discharge circuits before touching them.

DO NOT SERVICE OR ADJUST ALONE

Do not attempt any internal service or adjustment unless another person, capable of rendering first aid and resuscitation, is present.

DO NOT SUBSTITUTE PARTS OR MODIFY THE INSTRUMENT

Do not install substitute parts or perform any unauthorized modifications to this instrument. Return the instrument to B&K Precision for service and repair to ensure that safety features are maintained.

WARNINGS AND CAUTIONS

WARNING and CAUTION statements, such as the following examples, denote a hazard

and appear throughout this manual. Follow all instructions contained in these statements. A WARNING statement calls attention to an operating procedure, practice, or condition,

which, if not followed correctly, could result in injury or death to personnel. A CAUTION statement calls attention to an operating procedure, practice, or condition,

which, if not followed correctly, could result in damage to or destruction of parts or the entire product.

WARNING: Do not alter the ground connection. Without the protective ground connection, all

The power jack and mating plug of the power cable meet IEC safety standards.

WARNING:

Refer servicing to qualified personnel.

CAUTION:

voltage indicator. App

those of the specified voltage and current ratings.

CAUTION:

This product uses components which can be damaged by electro(ESD). To avoid damage, be sure to fo llow proper procedures for handling, storing and transporting parts and subassemblies which contain ESDcomponents.

SAFETY SYMBOL

This product is subject to Directive 2002/96/EC of the European Parliament and the Council of the European Union on waste

adopting that Directive, is marked as being put on the market after August 13, 2005, and should not be disposed of as unsorted

This symbol on an instrument indicates that the user should refer to the operating instructions located in the manual.

Electrical Shock hazard.

Chassis ground symbol.

CAT I (1000V)

CAT II (300V)

IEC Measurement Category II. Inputs may be connected to mains (up to 300 VAC) under Category II overvoltage conditions.

Compliance Statements

Disposal of Old Electrical & Electronic Equipment (Applicable in the European Union and other European countries with separate collection systems)

electrical and electronic equipment (WEEE) , and in jurisdictions

municipal waste. Please utilize your local WEEE collection facilities in the disposition of this product and otherwise observe all applicable requirements.

Table of Contents

Notice ................................................................................................................................................... 2

Safety Notice Supplement .................................................................................................................... 2

Safety Summary ................................................................................................................................... 2

Chapter 1 General In formation ........................................................................................................ 8

1.1 Feature Overview......................................................................................................................................... 8

1.2 Incoming Inspection .................................................................................................................................... 8

Chapter 2 Overview .......................................................................................................................... 9

2.1 Front Panel Overview .................................................................................................................................. 9

2.2 Annunciators on Screen ............................................................................................................................. 10

2.3 Front Panel Menu Reference ......................................................................................................................11

2.4 Front Panel Menu Overview ...................................................................................................................... 12

2.5 Rear Panel Summary ................................................................................................................................. 13

2.6 Power up .................................................................................................................................................... 14

2.6.1 Power Line Connection .............................................................................................................. 14

2.6.2 Input Terminals ............................................................................................................................ 14

2.6.3 Power-up Sequence ................................................................................................................... 16

2.6.4 High Energy Circuit Safety Precautions .................................................................................. 16

2.6.5 Power-on Defaults....................................................................................................................... 17

2.6.6 Warm-up time .............................................................................................................................. 17

2.7 Display ....................................................................................................................................................... 17

Chapter 3 Basic Measurements .................................................................................................... 18

3.1 Preparation ................................................................................................................................................. 18

3.2 Measuring Voltage ..................................................................................................................................... 18

3.2.1 Connections ................................................................................................................................. 18

3.3 Measuring Current ..................................................................................................................................... 19

3.3.1 Connections ................................................................................................................................. 20

3.3.2 Front Panel Fuse Replac ement ................................................................................................ 22

3.4 Measuring Resistance ................................................................................................................................ 23

3.4.1 Connections ................................................................................................................................. 23

3.5 Measuring Frequency and Period .............................................................................................................. 24

3.5.1 Trigger Level a nd Measurement Errors ................................................................................... 24

3.5.2 Gate Time ..................................................................................................................................... 24

3.5.3 Connections ................................................................................................................................. 24

3.6 Measuring Continuity ................................................................................................................................ 25

3.6.1 Connections ................................................................................................................................. 26

3.7 T esting Diode ............................................................................................................................................. 26

3.7.1 Connections ................................................................................................................................. 26

3.8 Measuring True RMS AC+DC .................................................................................................................. 27

3.8.1 Connections ................................................................................................................................. 27

3.8.2 Using the 2nd parameter display ............................................................................................... 28

3.9 Math Functions .......................................................................................................................................... 29

3.9.1 Percent ......................................................................................................................................... 29

3.9.2 dB Calculation .............................................................................................................................. 30

3.9.3 dBm Calculation .......................................................................................................................... 31

Chapter 4 Measurement Options .................................................................................................. 33

4.1 Measurement configuration ....................................................................................................................... 33

4.1.1 Range ........................................................................................................................................... 33

4.1.2 Relative ......................................................................................................................................... 34

4.1.3 Rate ............................................................................................................................................... 34

4.2 Trigger Operations ..................................................................................................................................... 35

4.2.1 Trigger procedure ........................................................................................................................ 35

4.2.2 Reading Hold ............................................................................................................................... 36

4.3 MAX / MIN ............................................................................................................................................... 36

4.4 Limit Operations ........................................................................................................................................ 36

4.4.1 Enabling limits .............................................................................................................................. 37

4.4.2 Setting Limit Values .................................................................................................................... 37

4.5 System Operations ..................................................................................................................................... 37

4.5.1 Beeper Control ............................................................................................................................ 38

4.5.2 Baud rate ...................................................................................................................................... 38

4.5.3 Selecting the Terminal Character .............................................................................................. 39

4.5.4 Key Sound .................................................................................................................................... 40

Chapter 5 Remote Operation ........................................................................................................ 41

5.1 USB & RS232 ........................................................................................................................................... 41

5.2 Serial Interface Operation .......................................................................................................................... 41

5.2.1 USB interface config ur ed as virtual COM RS232 inter f ace .................................................. 41

5.2.2 Sending and receiv ing data ....................................................................................................... 41

5.2.3 Selecting Baud Rate ................................................................................................................... 41

5.2.4 Software Prot ocol ........................................................................................................................ 42

5.3 Data Format ............................................................................................................................................... 42

Chapter 6 SCPI Command Reference ........................................................................................ 43

6.1 Command structure .................................................................................................................................... 43

6.2 Command Syntax....................................................................................................................................... 43

6.2.1 Commands and co m m and parameters ................................................................................... 43

6.2.2 Short-form Rules ......................................................................................................................... 45

6.2.3 Basic Rules of Command Structure ......................................................................................... 45

6.2.4 Multiple Command Rules ........................................................................................................... 46

6.2.5 Command Path Rules ................................................................................................................ 46

6.3 Command Reference ................................................................................................................................. 46

6.3.1 DISPlay subsystem ..................................................................................................................... 46

6.3.2 FUNCtion subsystem .................................................................................................................. 48

6.3.3 VOLTage subsystem ................................................................................................................... 49

6.3.4 CURRent subsystem .................................................................................................................. 53

6.3.5 RESistance subsystem .............................................................................................................. 57

6.3.6 FREQuency and PE Riod subsystem ....................................................................................... 60

6.3.7 TRIGger subsystem .................................................................................................................... 62

6.3.8 FETCH Subsystem ..................................................................................................................... 63

6.3.9 SYSTem Subsystem ................................................................................................................... 63

6.3.10 Common Commands ............................................................................................................... 64

Chapter 7 Specifications ................................................................................................................ 65

SERVICE INFORMATION ............................................................................................................... 73

LIMITED WARRANTY .................................................................................................................... 74

Chapter 1 General Information

1.1 Feature Overview

The 2831E 4½ digit and 5491B 50,000 count multimeters provide measurements with high accuracy, great stability and fast measurement rates. The meters provide a maximum measurement rate of 25 readings/sec and a 0.02% and 0.03% DC voltage basic accuracy for model 5491B and 2831E respectively. Both meters have broad measurement ranges:

 DC voltage from 50 μV to 1000 V  AC (RMS) voltage from 1 mV to 750 V  DC current from 100 nA to 20 A  AC (RMS) current from 100n A to 20 A  Two -wire resistance from 10 mΩ to 20 MΩ (50 MΩ for mode l 549 1B)  Frequency from 5 Hz to 1 MHz

Some additional cap abilities:

 Full range of functions: In addition t o tho se list ed ab ov e, the meter functions includ e per iod, d B,

dBm, continuity, diode testing, max, min and percent. Programming languages and remote control interfaces: The meters are programmable via US B (Virtual COM) interface using SCPI commands

1.2 Incoming Inspection

Please inspect the instrument mechanically and electrically upon receiving it. Unpack all item s f rom the shipping carton, and check for any obvious signs of physical damage that may have occurred during transportation. Report any damage to the shipping agent immediately. Save the original packing carton for possible future reshipment. The followin g items are included with ev er y order:

 Multimeter  Test leads  Power cord  Sp ar e f use  Operation Manual  Calibration certificate and test report

Verify that all items above are included in the shipping container. If anything is missing, please contact B&K Precision.

Chapter 2 Overview

2.1 Front Panel Overview

The front panel of the multimeter is shown in Figure 2-1. This figure includes s ome import ant abbrevi ated information that should be reviewed before operatin g t he instr ument.

1. Function keys Input terminals

Current Input fuse

Primary Display

Secondary Display

On /off Switch

2. Math function key

5. Range

1. Measurement Function keys (shifted and unshifted) Select measurement function: DC voltage and current, AC voltage and current, resistance,

continuity, frequency, period, dB, dBm, True RMS AC+DC and diode test .

2. Math function keys Select the math function: Rel, %, Max/Min, Comp and Hold.

3. 2

4. Menu operation keys

Display and speed key

Changes reading rate: Fast, Medium and Slow.

→ turns on/ off the 2nd parameter display.

→ Open/Close menu

Move through selections w it hin me nu level, command level or parameter level Move through selections w ithin menu level, command level or parameter leve l. Move up a level.

Selection

4. Menu Operation

Figure 2-1 Front Panel

3. 2

Display

And speed key

7. Shift/local Key

6. Hold/Trig Key

Move down a level.

(ENTER) Save the change made on “parameter” level, and retur n t o the “command” level. Cancel the change m ade on “parameter” level, and return to the “command” level.

5. Range and Combinat ion func tion se lecting keys

Trig

Select a 2nd display parameter

Select a higher range and disable auto ranging.

Select a lower range and disable auto ranging.

Toggle between auto ranging and manu al ranging.

6. Trig/ Hold Key Trigger a me asur ement from the front p anel.

Hold a reading on the display.

7. Shift/Local keys

Used to access shifted keys. (LOCAL) Cancel remote control mode and back to the LO CA L mode.

2.2 Annunciators on Screen

Figure 2-2 Display A nnunciat ors

FAST Fast reading rate MED Medium reading rate SLOW Slow reading rate TRIG Indicates trigger (front panel, bus) selected. HOLD Reading HOLD function is enabled REL Relative reading displayed MATH A math operation is enabled (%, dB, dBm).

(Speaker) Beeper on for continuity testing function

(Diode) Instrument is in diode test ing function

DC DC operation is enabled

AC AC operation is enabled

COMP Limit test ing function is enabled

HI/IN/LO Indicates t he li m it t esting results RMT Multimeter is in remote control mode AUTO Auto ranging enabled Max/Min MAX / MIN operation is enabled ERR Hardware or remote control err or det ec t ed SHIFT Accessing shifted keys

2.3 Front Panel Menu Reference

A：MATH MEN U

1: HI LIMIT → 2: LO LIMIT → 3: PERC REF → 4: dB REF→ 5: dBm REF

1. HI LIMIT Set the high limit for limit testing.

2. LO LIMIT Set the low limit for limit testing.

3. PERC REF Set the reference value for PERCENT function

4. dB REF Set the dB reference voltage value.

5. dBm REF Set the dBm reference impedance value.

B：TRIGGER MENU

1: TRIG MOD

1. TRIG MOD Select IMMediate, Manual or Bus trigger source mode.

C：SYSTEM MENU

1: BEEP STA → 2: BAUD RAT → 3: TX TERM → 4: RETURN → 5: KEY SONG → 6: REVISION

1. BEEP STA Enable or disable the beeper funct io n

2. BAUD RA T Select the baud rate for USB (virtual COM) or RS232 (Model 5491B only) operation.

3. TX TERM Set the terminal character for USB (virtual COM) or RS232 (Model 5491B

only) operation, which identifies the end of a command string

4. RETURN Sets whether to enable Echo of the “sent” SCPI commands in return string.

(i.e. if ON, sending *IDN? will return with *IDN? and model information on two separate lines).

5. KEY SONG Enable or disable the key sound when you press a key.

6. REVISION Shows the model number and firmware versio n of the instrument.

2.4 Front Panel Menu Overview

The menu is organized in a top-down tree structure with three levels (menus, commands and

parameters) as shown in Figure 2-3. You can use down ( one level to another. Each of the thr ee levels has se veral horizont a l choices which y ou can view by using

left (

 To turn on the menu, press  To turn off the menu, press

 To confirm a change on the “parameter” level, pres s  To cancel a change on the “parameter” level, pr es s

) or right ( ).

Menus

Commands

Parameters

Figure 2-3 Menu Tree

→ (Menu).

→ (Menu), or press any of the function or math keys on

the front panel.

) or up ( ) to move menu tree from

(ENTER).

(Menu).

Note: If you press on the “menu” level, this is the top level of the menu an d you ca nnot

go any higher; similarly if you press the menu and you cannot go any lower.

on the “parameter” level, this is the bottom level of

2.5 Rear Panel Summary

The rear panel of the multimeter is shown in Figure 2-4. This section includes important information that should be reviewed before oper ating the instrument.

Figure 2-4 Rear Panel

1. USB Device Port Connection port for USB rem ot e c ont r ol.

2. Grounding Chassis Grounding terminal

3. Power-Line Fuse-Holder Assembly The multimeter can be configured for line voltage of 110/220 V ± 10% AC at line frequency of 50/60 Hz ± 5%. Power-line fuse is used for instrument prot ection. (220 V/500 mA or 110 V/1 A)

Note: Please use the same-type fuse. To verify and replace the fuse, remove the power

cable and pull out the fuse holder. To select bet w een line volt age operations of 110 V or 220 V, turn the grey colored fuse holder until the correct line voltage label is shown on the outer win dow of t he fus e holder. It should say “110” or “220 ” de pen din g w hic h way you turn it.

4. RS232 Communication Port (Model 5491B only) Connection port for remote control via RS232.

2.6 Power up

2.6.1 Power Line Connection

Follow the procedure below to connect the multimeter to line power and turn on t he instr ument.

1. Check to make sure that the line voltage is in the correct range of 110 V or 220 V ± 10% (198 V to

242 V) and line frequency is in the range of 60 Hz or 50 Hz ± 5% (or 47.5 to 52.5 Hz) and that the line voltage switch is in the correct position before connecting the power cord. To che ck , f i rs t l ook at the label on the fuse co m partment to verify if it is shown as “110” or “220”. If it is not switched to the correct one, open up the fuse compartment and turn the grey fuse holder until it shows the correct voltage label (110 or 220) on the outer part of the fuse compartment. Then, check to make sure correct fuse value is used for the selected volt age operation.

CAUTION: Operating the instrument on an incorrect voltage may cause damage to the

instrument, possibly voidi ng the warranty.

2. Before plugging in t he power cord, make sure t hat the front panel pow er sw it ch is in the off posit ion.

3. Connect the female end of t he supplie d power c ord to t he AC receptacle on t he rear p anel. Co nnect

the other end of the power cord t o a gr ounded AC outlet.

WARNING: The power cord supplie d w ith t he multimeter contains a separate groun d wi re for use

with grounded outlets. When proper connections are made, instrument chassis is connected to pow er line groun d throug h the gro und w ire in t he power co rd. Fai lure to use a grounded outlet may r esult in personal injury or death due to electri c shoc k.

4. Turn on the instrument by pressing the front panel power switch and instrument is ready for

measuring.

2.6.2 Input Terminals

The input terminals are shown in Figure 2-5. The multimeter is protected against overloads up to the limits as shown in table 2-1. Exceeding these limits may result in a hazard to both the multimeter and operator.

2 mA-200 mA for 2831E, 5 mA-500 mA for model 5491B range DC/AC current input terminal for DC/AC current

Input-High terminal for Volts, ohms, Hz, period, diode and continuity measurements

Common terminal

2 A (5 A for model 5491B) and 20 A range current input terminal for DC/AC curren t meas ur ement

T1AL/250 V type fuse for the mA measurement range

Figure 2-5 Input terminals

Table 2-1 Input protection Limits

Function Input Terminals Maximum Allowable Input

DCV

ACV,HZ

mA, HZ

20A,HZ

All functions Any terminals to earth 1000V DC or 1000V peak AC

to COM to COM

500mA to COM

20A to COM

to COM to COM

1010V DC

757.5V AC RMS,1000V Peak 200mA (Model 5491B: 500 mA) DC or AC RMS 20A DC or AC RMS 500V DC or AC RMS 500V DC or AC RMS

2.6.3 Power-up S e que nce

On power-up, the multimeter performs self-tests on its EPROM and RAM and lights all segments and annunciators for about 1 second. If a failure is detected, the instrument momentarily displays an error message and the ERR annunciator turns on.

If the instrument passes self-tests, the fir mwar e r evision will be displayed momentarily.

2.6.4 High Energy Circuit Safety Precautions

To optimize safety when measuring voltage in high energy distribution circuits, read and use the directions in the following.

When making measurements in high energy circuits, use test leads and accessories that meet the following requirements:

 Test leads and accessories must be fu lly insulated.  Only use test leads that can be connected t o the circuit (e.g., alligator clip s, sp ade lugs, etc.) for

hands-off measureme nt s.

 Do not use test leads or accessories that decrease voltage spacing. This diminishes arc

protection and creates a hazardous condition.

Use the following sequenc e w hen measuring high energy circ uits:

1. De-energize the circuit using a regular installed connect-disconnect device, such as a circuit breaker , main switch, etc.

2. Attach the test leads to the circuit under t es t . Use appropriate safety rat ed t est leads .

3. Set the multimeter to the pr oper measurement funct ion and range.

4. Energize the circuit using the installed connect-disconnect device and make measurements without disconnecting the multimeter.

5. De-energize t he c ircuit using the installe d connect-disconnect device.

6. Disconnect the test leads from the circuit under t est .

WARNING: The maximum common-mode voltage (voltage between COM and the chassis

ground) is 500V peak. Exceeding this value may cause a breakdown in insulation, creating a shock hazard.

2.6.5 Power-on Defaults

2831E and 5491B have a factor y default setting for the pow er -on setting.

Since the basic measurement procedures in this manual assume the factory defaults, reset the instrument to the factory settings when following step-by-step procedures. Table 2-2 lists the factory default settings.

Table 2-2 Factory Default Settings

Setting Factory Default Function Range Rate Remote/Local Trigger Mo de Relative Mode Compare Mode HI Limit Lo Limit Percent Mode Reference Max/Min Mode Reading Hold Secondary Display Mode Cal Mode

DCV AUTO Medium Local Immediate OFF OFF +1

-1 OFF +1 OFF OFF OFF OFF

2.6.6 Warm-up time

The multimeter is ready for use as soon as the power-up sequence has completed. H ow ever, to achieve rated accuracy and stability, allow the instrument to warm up for half an hour. If the instrument has been subjected to extreme te m per at ur es, allow additional time for internal temperatures to s tabilize.

2.7 Display

The display of the multimeter is primarily used to display readings, along with the units and type of measurement. Annunciators located on the left, right and bottom indicate various states of operation. See section 2.2 for a complete listing of annunciators.

Chapter 3 Basic Measurements

ACV

DCV

ACV

3.1 Preparation

One of the first things you would like to do with your multimeter is to become acquainted with its front panel. We have provided some exercises in foregoing chapters about preparations for use and operations of front pa nel.

The front panel has six rows of keys to select v arious fu nctio ns a nd o perati ons. Most keys hav e a sh i fte d function printed in blue above the key. To perform a shifted function, press

will turn on). Then, press the key that has the desired label above it. For example, to select the AC current function, press

If you accidentally press

then press (ACI).

, just press it again to turn off the Shift annunciator.

3.2 Measuring Voltage

Voltage ranges: 200 mV, 2 V, 20 V, 200 V, 1000 V (750 VAC) (model 5491B: 500 mV, 5 V, 50 V, 500 V, 1000 V (750 VAC)) Maximum resolution: 50 μV for DC and 1 mV for AC (on 200 mV range (model 2831E) and on 500 m V range (model 5491B)) AC technique: true RMS, AC-coupled, 1000 V Peak AC

(the Shift annunciator

3.2.1 Connections

Assuming the multimeter is under factor y default conditions, the basic procedure is as follows:

1. Connect test leads to

2. Select DC or AC voltage me as urement by pressing or .

3. Press displayed when in auto ranging mode. If you want manual ranging, use the RANGE

4. Connect test leads to the sources as shown in Figure 3-1.

CAUTION: Do not apply more than 1000V peak to the input or i ns t r ument damages may occur.

5. In manual range, if the “OVL.D” message is displayed, press the up range until a desired reading is displayed (or press

possible range for the best r esolut i on.

6. Press

to toggle between auto and manual ranging. Notice that the AUTO annunciator is

keys to select a measurement r ange consistent with expected voltage.

+ to turn on the secondary display, Use or key to choose the

and COM terminals.

and

key to se lect a hi gher

key for auto ranging). Use the lowest

function for secondary dis play.

AC VOLTAGE SOURCE

DC VOLTAGE SOURCE

7. Ta ke rea dings from the display.

CAUTION: Maximum Input = 1010 V peak

Input Resistance = 10 MΩ

CAUTION: Maximum Input = 750 V RMS or 1000 V peak, 3x10

Model 2831E current measurement range: 2 mA, 20 mA, 200 mA, *2 A, *20 A Model 5491B current mea s urement range: 5 mA, 50 mA, 500 mA, *5 A, *20 A *Indicates range is availab le f or manual range only. Auto range will not work when reading requires

Input Impedance = 1.1 MΩ and 100 pF

Figure 3-1 DC and AC Voltage Measurement Connections

3.3 Measuring Current

V-Hz

setting to this range.

DCV

ACV

Maximum resolution: 100 nA ( on 2 mA range (on 5 mA range for model 549 1B)) Current measurement is a vailable in Auto range for the lower current measurement s only.

Note:

For 2831E, readings that are below 200 mA using the l ow current measure m ent in put can be set in auto

range. This means it will auto range bet w een 2 mA, 20 mA, and 200 mA range. For readings above 200 mA, auto range is

available. Manual range must be used to read any readings higher than 200

not mA. This means, for ranges 2 A and 20 A, only m anual range is available. Additionally, the high current measurement inp ut must be used to obtain meas urements in these two hig her r anges.

For 5491B, readings that are below 500 mA usin g the low current measurem ent input (fus e protected u p to 500 mA max.) can be set in auto range. This means it will auto range between 5 mA, 50 mA, and 500 mA range. For readings above 500 mA, auto range is

not available. Manual range must be used to read any readings higher t han 500 mA. This means, for ranges 5 A and 20 A, only manual range is available. Additionally, the high current measurement input mu st be used to obtain measureme nt s in these two higher ranges.

3.3.1 Connections

Assuming the multimeter is under factory default conditions, the basic procedure to measure current is as follows (users must use manual range for measurement, following step 3):

1. Connect test leads between 500 mA terminal (for lower current meas urement s) and COM terminal or

between 20 A terminal (for higher current measure m ents) and COM terminal.

2. Select DCI or ACI measurem ent f unct ion by pressing

3. Press

toggles auto ranging. Note that auto range is only available for readings that are below 200 mA (for 2831E) and 500 mA (for 5491B) and when using the 500 mA max. terminal and COM terminal connections. For readings above these limits, only manual range is available and the 20 A terminal and COM terminal must be used to obtain measurement results. If instrument shows the AUTO annunciator on display, press again to turn off auto ranging mode and go into

manual range mode. Use the RANGE and consistent with expected current.

4. Connect test leads to the source as shown in Figure 3-2.

CAUTION: Do not apply more than 1 A, 250 V to the 500 mA input terminal or the fuse will be blown. For measuring current higher than 500 mA(or 200 mA for model 2831E), use the 20 A terminal instead.

→ or → .

keys to select a measurement range

5. In manual range, if the “OVL.D” message is displayed, press up

key to select a higher range

until a desired reading is displayed. U se the lowest possible range for the best resolution. Press

+ to turn on the 2nd parameter display, Use or key to select function for

AC CURRENT SOURCE

DC CURRENT SOURCE

display.

6. Ta ke rea dings from the display.

(Model 2831E) DC Current measurement on Range: 2 mA, 20 mA, 200 mA (Model 5491B) DC Current measurement on Range: 5 mA, 50 mA, 500 mA

(Model 2831E) AC Current measurement on Range: 2 mA, 20 mA, 200 mA (Model 5491B) AC Current measurement on Range: 5 mA, 50 mA, 500 mA

(Model 2831E) DC Current measurement on Range: 2 A, 20 A

AC CURRENT SOURCE

DC CURRENT SOURCE

(Model 5491B) DC Current measurement on Range: 5 A, 20 A

(Model 2831E) AC Current measurement on Range: 2 A, 20 A (Model 5491B) AC Current measurement on Range: 5 A, 20 A

CAUTION: Maximum Input = 20 A DC or RMS Maximum test times : < 20 s

Figure 3-2 DC and AC Current Measurements

3.3.2 Front Panel Fuse Replacement

WARNING: Make sure the instrument is disconnected from the power line and other equipment

1. Turn off the power and disconn ec t t he pow er line and test leads.

2. From the front panel, use a screwdriver to rotate the fuse carrier several turns counter-clockwise. Take the fuse carrier out of the socket.

3. Remove the fuse and replace it with the same type ( T1AL, 250V, 5×20 mm ）.

before replacing the AMPS fuse.

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