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®
Model 187 & 189
True RMS Multimeter
Users Manual
August 2000, Rev.2, 6/02
© 2000, 2002 Fluke Corporation. All rights reserved. Printed in U.S.A. All product names are trademarks of their respective companies.
Lifetime Limited Warranty
Each Fluke 20, 70, 80, 170 and 180 Series DMM will be free from defects in material and workmanship for its lifetime. As used herein, "lifetime" is defined as seven years after Fluke discontinues manufacturing the product, but the warranty period shall be at least ten years from the date of purchase. This warranty does not cover fuses, disposable batteries, damage from neglect, misuse, contamination, alteration, accident or abnormal conditions of operation or handling, including failures caused by use outside of the product's specifications, or normal wear and tear of mechanical components. This warranty covers the original purchaser only and is not transferable. For ten years from the date of purchase, this warranty also covers the LCD. Thereafter, for the lifetime of the DMM, Fluke will replace the LCD for a fee based on then current component acquisition costs. To establish original ownership and prove date of purchase, please complete and return the registration card accompanying the product, or register your product on http://www.fluke.com. Fluke will, at its option, repair at no charge, replace or refund the purchase price of a defective product purchased through a Fluke authorized sales outlet and at the applicable international price. Fluke reserves the right to charge for importation costs of repair/replacement parts if the product purchased in one country is sent for repair elsewhere. If the product is defective, contact your nearest Fluke authorized service center to obtain return authorization information, then send the product to that service center, with a description of the difficulty, postage and insurance prepaid (FOB Destination). Fluke assumes no risk for damage in transit. Fluke will pay return transportation for product repaired or replaced in-warranty. Before making any non-warranty repair, Fluke will estimate cost and obtain authorization, then invoice you for repair and return transportation. THIS WARRANTY IS YOUR ONLY REMEDY. NO OTHER WARRANTIES, SUCH AS FITNESS FOR A PARTICULAR PURPOSE, ARE EXPRESSED OR IMPLIED. FLUKE SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LOSSES, INCLUDING LOSS OF DATA, ARISING FROM ANY CAUSE OR THEORY. AUTHORIZED RESELLERS ARE NOT AUTHORIZED TO EXTEND ANY DIFFERENT WARRANTY ON FLUKE'S BEHALF. Since some states do not allow the exclusion or limitation of an implied warranty or of incidental or consequential damages, this limitation of liability may not apply to you. If any provision of this warranty is held invalid or unenforceable by a court or other decision-maker of competent jurisdiction, such holding will not affect the validity or enforceability of any other provision. Fluke Corporation P.O. Box 9090 Everett, WA 98206-9090 U.S.A. 2/02 Fluke Europe B.V. P.O. Box 1186 5602 BD Eindhoven The Netherlands
Table of Contents
Chapter
1
Title
Page
Before You Start .......................................................................................................... 1-1 Safety Information.......................................................................................................... 1-1 Contacting Fluke............................................................................................................ 1-1 Symbols ......................................................................................................................... 1-4
2
Getting Acquainted...................................................................................................... 2-1 Introduction.................................................................................................................... Turning the Meter On..................................................................................................... Battery Considerations .................................................................................................. Automatic Power Off ................................................................................................. Automatic Backlight Off............................................................................................. Low Battery Indication............................................................................................... Rotary Switch................................................................................................................. Pushbuttons................................................................................................................... 2-1 2-1 2-2 2-2 2-3 2-3 2-4 2-5
i
Model 187 & 189
Users Manual Selecting the Range....................................................................................................... Understanding the Display ............................................................................................. Primary Display ......................................................................................................... Secondary Display..................................................................................................... Bar Graph.................................................................................................................. Using the Input Terminals .............................................................................................. Using Display Hold ......................................................................................................... Using AutoHOLD............................................................................................................ Using MIN MAX.............................................................................................................. Using FAST MN MX ....................................................................................................... Using HOLD with MIN MAX or FAST MN MX............................................................ Using Relative Mode (REL)............................................................................................ 3 2-10 2-10 2-10 2-11 2-11 2-17 2-18 2-19 2-19 2-21 2-22 2-22
Making Measurements................................................................................................. 3-1 Introduction .................................................................................................................... Measuring Voltage ......................................................................................................... Measuring AC Voltage............................................................................................... dB Measurements in AC Volts Functions .................................................................. Measuring DC Voltage .............................................................................................. Both AC and DC Voltage Measurements .................................................................. Measuring Resistance.................................................................................................... Testing for Continuity ..................................................................................................... Using Conductance for High Resistance Tests .............................................................. Measuring Capacitance.................................................................................................. Testing Diodes ............................................................................................................... Measuring Temperature ................................................................................................. Measuring Current ......................................................................................................... Input AlertTM Feature ................................................................................................. 3-1 3-1 3-2 3-3 3-4 3-4 3-6 3-8 3-9 3-12 3-13 3-15 3-16 3-17
ii
Contents (continued)
Measuring AC Current .............................................................................................. Measuring DC Current .............................................................................................. Measuring Frequency .................................................................................................... Measuring Duty Cycle.................................................................................................... Measuring Pulse Width.................................................................................................. 4 3-18 3-20 3-22 3-23 3-25
Using Memory & Communications Features ............................................................ 4-1 Introduction.................................................................................................................... Types of Memory ........................................................................................................... Saved Readings Memory.......................................................................................... Logged Readings Memory........................................................................................ Storing Saved Readings ................................................................................................ Starting Logging ............................................................................................................ Stopping Logging........................................................................................................... Viewing Memory Data.................................................................................................... Clearing Memory ........................................................................................................... Using Communications (187 and 189) .......................................................................... 4-1 4-1 4-1 4-1 4-2 4-2 4-2 4-3 4-5 4-5
5
Changing the Default Settings ................................................................................... 5-1 Introduction.................................................................................................................... Selecting Setup Options ................................................................................................ Adjusting the Temperature Offset.................................................................................. Selecting Display Resolution (3 1/2 or 4 1/2 Digits)...................................................... Setting the Power Off Timeout....................................................................................... Setting the 24-Hour Clock.............................................................................................. Setting the Line (Main) Frequency................................................................................. Returning to Factory Defaults ........................................................................................ Saving Setup Options .................................................................................................... 5-1 5-1 5-4 5-6 5-6 5-7 5-7 5-8 5-8
iii
Model 187 & 189
Users Manual 6 Maintenance ................................................................................................................. 6-1 Introduction .................................................................................................................... General Maintenance..................................................................................................... Testing the Fuses........................................................................................................... Replacing the Batteries .................................................................................................. Replacing the Fuses ...................................................................................................... User-Replaceable Parts ................................................................................................. In Case of Difficulty ........................................................................................................ 7 6-1 6-1 6-1 6-3 6-5 6-5 6-5
Specifications............................................................................................................... 7-1 Safety and Compliances ................................................................................................ Physical Specifications................................................................................................... Feature Summary........................................................................................................... Basic Specifications ....................................................................................................... Detailed Accuracy Specifications ................................................................................... Frequency Counter Sensitivity ....................................................................................... Burden Voltage (A, mA, µA) ........................................................................................... Input Characteristics....................................................................................................... 7-1 7-2 7-3 7-4 7-5 7-11 7-11 7-12
iv
List of Tables
Table
1-1. 1-2. 2-1. 2-2. 2-3. 3-1. 4-1. 5-1. 5-2. 6-1.
Title
Safety Information................................................................................................................. International Electrical Symbols............................................................................................ Rotary Switch Selections ...................................................................................................... Pushbuttons.......................................................................................................................... Display Features ................................................................................................................... Current Measurement ........................................................................................................... View Display ......................................................................................................................... Function Specific Setup Selections....................................................................................... Common Setup Selections ................................................................................................... User-Replaceable Parts........................................................................................................
Page
1-2 1-4 2-6 2-8 2-13 3-16 4-4 5-2 5-3 6-6
v
Model 187 & 189
Users Manual
vi
List of Figures
Figure
2-1. 2-2. 2-3. 2-4. 2-5. 2-6. 2-7. 2-8. 3-1. 3-2. 3-3. 3-4. 3-5. 3-6. 3-7. 3-8. 3-9.
Title
AC Volts Display ................................................................................................................... Rotary Switch........................................................................................................................ Pushbuttons.......................................................................................................................... Display Features ................................................................................................................... Input Terminals ..................................................................................................................... Display Hold and AutoHOLD ................................................................................................ Min Max Avg ......................................................................................................................... Relative Mode....................................................................................................................... AC Voltage Measurement..................................................................................................... dBm Display.......................................................................................................................... AC and DC Display ............................................................................................................... DC Voltage Measurement..................................................................................................... Resistance Measurement ..................................................................................................... Continuity Test...................................................................................................................... Conductance Measurement.................................................................................................. Capacitance Measurement ................................................................................................... Diode Test ............................................................................................................................
Page
2-2 2-4 2-5 2-12 2-17 2-18 2-21 2-22 3-2 3-3 3-5 3-6 3-7 3-10 3-11 3-13 3-14
vii
Model 187 & 189
Users Manual 3-10. 3-11. 3-12. 3-13. 3-14. 3-15. 3-16. 3-17. 3-18. 4-1. 5-1. 6-1. 6-2. Temperature Measurement ................................................................................................... AC Current Measurement...................................................................................................... DC Current Measurement ..................................................................................................... Functions Allowing Frequency Measurement........................................................................ Hz Display ............................................................................................................................. Duty Cycle Measurements .................................................................................................... Duty Cycle Display ................................................................................................................ Pulse Width Measurements................................................................................................... Pulse Width Display .............................................................................................................. View Display.......................................................................................................................... Adjusting Temperature Offset ............................................................................................... Testing the Current Fuses..................................................................................................... Battery and Fuse Replacement ............................................................................................. 3-15 3-19 3-21 3-22 3-23 3-24 3-25 3-26 3-27 4-4 5-5 6-2 6-4
viii
Chapter 1
Before You Start
Safety Information
The Fluke Model 187 and Model 189 True RMS Multimeters (hereafter referred to as the "meter") comply with: · · · · · · EN61010.1:1993 ANSI/ISA S82.01-1994 CAN/CSA C22.2 No. 1010.1-92 1000V Overvoltage Category III, Pollution Degree 2 600V Overvoltage Category IV, Pollution Degree 2 UL 3111-1
Contacting Fluke
To order accessories, receive assistance, or locate the nearest Fluke distributor or Service Center, call: USA: 1-888-99-FLUKE (1-888-993-5853) Canada: 1-800-36-FLUKE (1-800-363-5853) Europe: +31 402-678-200 Japan: +81-3-3434-0181 Singapore: +65-738-5655 Anywhere in the world: +1-425-446-5500 Address correspondence to: Fluke Corporation P.O. Box 9090, Everett, WA 98206-9090 USA Fluke Europe B.V. P.O. Box 1186, 5602 BD Eindhoven The Netherlands
Use the meter only as specified in this manual. Otherwise, the protection provided by the meter may be impaired. Refer to safety information in Table 1-1. A Warning identifies conditions and actions that pose hazards to the user. A Caution identifies conditions and actions that may damage the meter or the equipment under test.
Visit us on the World Wide Web at: www.fluke.com
1-1
Model 187 & 189 Users Manual Table 1-1. Safety Information
WWarning
To avoid possible electric shock or personal injury, follow these guidelines: · · · · · · · · · · · Do not use the meter if it is damaged. Before you use the meter, inspect the case. Look for cracks or missing plastic. Pay particular attention to the insulation surrounding the connectors. Inspect the test leads for damaged insulation or exposed metal. Check the test leads for continuity. Replace damaged test leads before you use the meter. If this product is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired. Do not use the meter if it operates abnormally. Protection may be impaired. When in doubt, have the meter serviced. Do not operate the meter around explosive gas, vapor, or dust. Do not apply more than the rated voltage, as marked on the meter, between terminals or between any terminal and earth ground. Before use, verify the meter's operation by measuring a known voltage. When measuring current, turn off circuit power before connecting the meter in the circuit. Remember to place the meter in series with the circuit. When servicing the meter, use only specified replacement parts. Use caution when working above 30 V ac rms, 42 V peak, or 60 V dc. Such voltages pose a shock hazard. Avoid working alone.
1-2
Before You Start Safety Information Table 1-1. Safety Information (cont.)
1
WWarning
· · · · · · · When using the probes, keep your fingers behind the finger guards on the probes. Connect the common test lead before you connect the live test lead. When you disconnect test leads, disconnect the live test lead first. Remove test leads from the meter before you open the battery door. Do not operate the meter with the battery door or portions of the cover removed or loosened. To avoid false readings, which could lead to possible electric shock or personal injury, replace the batteries as soon as the low battery indicator (M) appears. Use only type AA batteries, properly installed in the meter case, to power the meter. To avoid the potential for fire or electrical shock, do not connect the thermocouples to electrically live circuits.
Caution
To avoid possible damage to the meter or to the equipment under test, follow these guidelines: · Disconnect circuit power and discharge all high-voltage capacitors before testing resistance, continuity, diodes, or capacitance. · Use the proper terminals, function, and range for your measurements. · Before measuring current, check the meter's fuses and turn power OFF to the circuit before connecting the meter to the circuit.
1-3
Model 187 & 189 Users Manual
Symbols
Symbols used on the meter and in this manual are explained in Table 1-2. Table 1-2. International Electrical Symbols AC (Alternating Current) DC (Direct Current) AC and DC Battery Complies with relevant Canadian Standards Association directives Inspected and licensed by TÜV Product Services. Earth ground Fuse Double insulated Important information Complies with European Union directives Underwriters Laboratories, Inc.
1-4
Chapter 2
Getting Acquainted
Introduction
Although this manual describes the operation of both Models 187 and 189, all illustrations and examples assume use of Model 189. Additional capabilities with Model 189 are discussed in Chapter 4. These capabilities include the following: · · · · An enhanced memory function that features an additional position (VIEW MEM) on the rotary switch. Logging Save Memory
Turning the Meter On
To turn the meter on, turn the rotary switch from OFF to any switch setting. The ac volts function (shown in Figure 2-1) is assumed in the following discussion. You do not need connections to the input terminals at this time. If you want a view of the full display (all segments illuminated), press and hold Q while turning the meter on. Release the button when you are done viewing the full display.
2-1
Model 187 & 189 Users Manual
Automatic Power Off
The display blanks and the meter goes into a "sleep" mode if you have not changed the rotary switch position or pressed a button for a set period. While in Sleep mode, pressing any button turns the meter on. The meter then returns to the display for the function selected with the rotary switch; all previously activated button features (HOLD, Hz, etc.) are discarded. The automatic power off is preset to 15 minutes. From the Setup menu (see Chapter 5), you can specify a maximum period of 23 hours, 59 minutes. If you set the period to 0, the meter remains on until you turn the rotary switch to OFF or the batteries become too weak. Automatic power off does not occur if the meter is in MIN MAX, FAST MN MX, AutoHOLD, or LOGGING (Model 189) mode.
tc031f.eps
Figure 2-1. AC Volts Display
Battery Considerations
The meter uses four AA alkaline batteries. The following paragraphs describe several techniques used to conserve battery power.
2-2
Getting Acquainted Battery Considerations
2
Automatic Backlight Off
Press T to select the backlight level (low, high, or off.) In low or high, the backlight turns off automatically after a given period. This period is also preset to 15 minutes and can be set to a maximum of 99 minutes from the setup menu. If the period is set to 0, the backlight is on indefinitely and can only be turned off by pressing T or turning the meter off. Note See Chapter 5 for power off and backlight off setup information.
Low Battery Indication
A constant battery icon ( B) in the upper left corner of the display notifies you that the batteries are low and should be replaced.
WWarning
To avoid false readings, which could lead to possible electric shock or personal injury, replace the batteries as soon as the battery icon ( B) appears. A flashing battery icon means that battery failure is imminent. The backlight cannot be used in this condition. MIN MAX and FAST MN MX features turn off. For Model 189, logging and communications also cease.
2-3
Model 187 & 189 Users Manual
Rotary Switch
Turn the meter on by selecting any measurement function (identified with white letters around the rotary switch). The meter presents a standard display for that function (range, measurement units, modifiers, etc.) The display may also be influenced by some of the choices made in Setup. Use the blue button to select any rotary switch alternate function (labeled in blue letters). You can also use other buttons to choose modifiers for the selected function. When you turn the rotary switch from one function to another, a display for the new function appears. Button choices made in one function do not carry over into another function. With Model 189, a VIEW MEM switch position is available; refer to Chapter 4 for more information.
The rotary switch is shown in Figure 2-2. Each position is described in Table 2-1.
nS
ac+dc
mV
F C
V ac+dc mV
dB dB
A mA
A
A mA
V
ac+dc
OFF
A
ac+dc
VIEW MEM
CLEAR MEM
tc012f.eps
Figure 2-2. Rotary Switch
2-4
Getting Acquainted Pushbuttons
2
Pushbuttons
The buttons activate features that augment the function selected with the rotary switch. The buttons are shown in Figure 2-3 and described in Table 2-2. Use the blue button ( %) to access functions labeled in blue for some of the rotary switch positions. Table 2-1 defines all blue button functions. Use the yellow button ( O) followed by other buttons to access additional features. These features appear in yellow above the appropriate keys. Table 2-2 defines yellow button features. This manual identifies the yellow button feature in parentheses following the button sequence . For example, activating the FAST MN MX mode appears as O M (FAST MN MX).
AutoHOLD FAST MN MX LOGGING YES
HOLD
MIN MAX
CANCEL
REL
SAVE NO
Hz % ms
SETUP
RANGE
tc013f.eps
Figure 2-3. Pushbuttons The following yellow button features are not available on Model 187: (YES), (NO), (LOGGING), and (SAVE).
2-5
Model 187 & 189 Users Manual Table 2-1. Rotary Switch Selections Position Rotary Switch Function AC voltage measurement from 0 V to 1000.0 V % Blue Key Function dB over AC, AC over dB
\ , $ m
j
AC millivolt measurement from 0 mV to 3000.0 mV
dB over AC, AC over dB
DC voltage measurement from 0 V to 1000.0 V
AC over DC (AC in primary display, DC in secondary display), DC over AC, ac+dc AC over DC (AC in primary display, DC in secondary display), DC over AC, ac+dc Continuity test Conductance measurement from 0 nS to 50.00 nS
DC millivolt measurement from 0 mV to 3000.0 mV
Resistance measurement from 0 to 500.0 M
z
w
2-6
Capacitance measurement from 0.001 nF to 50 mF
Diode test
Temperature measurement
Toggles between °C and °F.
Getting Acquainted Pushbuttons Table 2-1. Rotary Switch Positions (cont.) Position Rotary Switch Function AC current measurements from 0 mA to 20.000 A none % Blue Key Function
2
I = K x
VIEW MEM
AC current measurements from 0 µA to 5000.0 µA
none
DC current measurements from 0 mA to 20.000 A
AC over DC (AC in primary display, DC in secondary display), DC over AC, ac+dc AC over DC (AC in primary display, DC in secondary display), DC over AC, ac+dc CLEAR MEM. See Chapter 4 for more information.
DC current measurements from 0 µA to 5000.0 µA
(Model 189 only.) Access data held in the meter's memory. See Chapter 4 for more information.
2-7
Model 187 & 189 Users Manual Table 2-2. Pushbuttons Yellow Button Function Note Press O to access "Yellow Button Functions." The O box and the 24-hour clock appear in the lower corners of the display and the primary display freezes, allowing time to press a second button. T l Q M Press to turn backlight on or off. Also, in Setup, use the arrow function (l) to select the previous digit or item in a list. Press to freeze the displayed value. Press again to release the display. Press to start retaining min, max, and average values. Press successively to display max, min, and average values. Press O N (CANCEL) to stop. Press to store the present reading as an offset reference; subsequent readings show only the relative difference from this value. Press again to show the difference as a percentage of the reference.
SETUP
Button
Description
Description
O
T
Press to access Setup selections. Press to store a Setup selection and proceed to the next selection. Press to begin AutoHOLD; the last stable reading is displayed. Press to start FAST MN MX mode, where min and max values for short duration events are stored. Press to start and stop Logging (Model 189). Press O + N (CANCEL) to stop.
AutoHOLD
O Q
FAST MN MX
O M
D
LOGGING
O D
2-8
Getting Acquainted Pushbuttons Table 2-2. Pushbuttons (cont.) Yellow Button Function (none)
2
Button [ · · · · · · · ·
Description In Setup, increment a digit . In counter functions, select positive pulse slope. In ohms continuity, select beep on open. In VIEW MEM, see Chapter 4 (Model 189). In Setup, decrement a digit . In counter functions, select negative pulse slope. In ohms continuity, select beep on short. In VIEW MEM, see Chapter 4 (Model 189).
Description
]
(none)
R
Exit AUTO and enter MANUAL ranging. In MANUAL, select next input range. Press O N (CANCEL) to return to AUTO. Successively press for frequency, duty cycle, and pulse width. The blue button. Press to access blue functions on the rotary switch. In Setup, use arrow function ( s) to select the next digit or item in a list.
SAVE
O R
Press to save present reading (Model 189) CANCEL any % (blue key) function and all other button features.
N % s
CANCEL
O N (none)
2-9
Model 187 & 189 Users Manual
Selecting the Range
Press R to select either a fixed range or the autorange feature. Note You cannot use R in conductance, diode test, and temperature functions or with the REL, MIN MAX, and FAST MN MX features. These selections all use a specific fixed range. Autoranging (AUTO lighted in the display) always comes on initially when you select a new function. In autorange, the meter selects the lowest input range possible, ensuring that the reading appears with the highest available precision (resolution). If AUTO is already on, press R to enter MANUAL ranging in the present range. You can then select the next manual range each time you press R. Return to autoranging by pressing O N (CANCEL).
Understanding the Display
Display features are shown in Figure 2-4 and described in Table 2-3. Major display features are described in the following paragraphs. Note You can show all display segments (as shown in Figure 2-4) by pressing Q while turning the meter on. Release Q to turn off the full display.
Primary Display
The primary display usually shows the present reading for the rotary switch function. For most of these functions, the primary display can be set to show 4 or 5 digits. See Chapter 5 for more information about display digits. Other uses for this display are: · · AutoHOLD: most recent held reading. MIN MAX: maximum, minimum, or average value.
2-10
Getting Acquainted Understanding the Display · · · · · dB (in ac volts functions): the dBm or dBV value. REL: the difference between the present reading and a stored reference reading. Setup: various messages (see Chapter 5). Overload conditions: OL displayed. Error conditions.
2
Bar Graph
The bar graph provides an analog indication of the measured input. For most measurement functions, the bar graph updates 40 times per second. Since this response is much faster than the digital display, the bar graph is useful for making peak and null adjustments and for observing rapidly changing inputs. The bar graph is not available in temperature, capacitance, ac over dc, dc over ac, and ac+dc functions.
Secondary Display
The secondary display often shows the present reading when the primary display shows some other feature (MIN MAX, REL , etc.) When multiple features are active, the secondary display shows one of the values. For example, Hz could appear in the secondary display while dB appears in the primary display.
2-11
Model 187 & 189 Users Manual
8 7 6 5 4 3 2 1 9
10 11
12
13
14
17
16
15
tc011f.eps
Figure 2-4. Display Features
2-12
Getting Acquainted Understanding the Display Table 2-3. Display Features Number ~ Feature Continuity test function is selected. Description
2
<
p e
>
Bar Graph. In normal operation 0 (zero) is on the left. In Relative %, 0 is in the center, negative values are to the left and positive to the right. The polarity indicator left of the bar graph shows the polarity of the input. Both polarity indicators appear in REL% mode. The arrow right of the bar graph indicates an overload condition. Both arrows appear (without bar graph) when you can use T (l) and % (s) to select settings in the setup mode. Percent difference in Relative mode is being displayed in the primary display. The reference value is shown in the secondary display Relative (REL ) mode is active. The primary display has been modified by the reference value shown in the secondary display. Indicates negative readings. In Relative mode, this sign indicates that the present input is less than the stored reference. >30 V ac and/or dc may be present at the input terminals. Low battery. If flashing, battery failure is imminent, and logging and backlight are disabled.
Z
B
WWarning
To avoid false readings, which could lead to possible electric shock or personal injury, replace the battery as soon as the low battery indicator appears.
2-13
Model 187 & 189 Users Manual Table 2-3. Display Features (cont.) Number Feature Description FAST MN MX mode is enabled. ( O M) Minimum reading displayed. Maximum reading displayed. Average reading displayed. Readings are being recorded in memory (Model 189 only.) ( O + D) The meter is in Hold mode. ( Q) AutoHOLD is active. ( O + Q) Primary Display (4-1/2 digit) Overload input. Measurement Units
FAST MIN MAX AVG
; g gS
8.8.8.8.8 0L
V, mV dBm, dBV
V: Volts. The unit of voltage. mV: Millivolt. 1 x 10-3 or 0.001 volts. For ac volts functions, reading is shown in decibels of power above or below 1 mW (dBm) or decibels of voltage above or below 1 V (dBV).
2-14
Getting Acquainted Understanding the Display Table 2-3. Display Features (cont.) Number Feature Description For dc volts and dc amps functions, reading represents the rms total of ac and dc measurements. : Ohm. The unit of resistance. k: Kilohm. 1 x 103 or 1000 ohms. M: Megohm. 1 x 106 or 1,000,000 ohms. S: Siemens. The unit of conductance. nS: Nanosiemens. 1 x 10-9 or 0.000000001 Siemens. F: Farad. The unit of capacitance. nF: Nanofarad. 1 x 10-9 or 0.000000001 farads. µF: Microfarad. 1 x 10-6 or 0.000001 farads. mF: Millifarad. 1 X 10 -3or 0.001 farads. Degrees Celsius (default) or Fahrenheit. A: Amperes (amps). The unit of current. mA: Milliamp. 1 x 10-3 or 0.001 amperes. µA: Microamp. 1 x 10-6 or 0.000001 amperes. Hz: Hertz. The unit of frequency. kHz: Kilohertz. 1 x 103 or 1000 hertz. MHz: Megahertz. 1 x 106 or 1,000,000 hertz.
2
AC+DC e, ke Me, nS nF, µF, mF
°C ,°F A, mA, µA
Hz, kHz, MHz
2-15
Model 187 & 189 Users Manual Table 2-3. Display Features (cont.) Number Feature 51000 AUTO MANUAL Range. Digits display range in use. Time Display. Used with HOLD, AutoHOLD, MIN MAX, FAST MN MX (SAVE, and LOGGING Model 189). Elapsed Time Display (f on): shown in minutes:seconds to maximum of 59:59 - used if time since Min, Max, or Logging started is less than 60 minutes. Always used for Min, Max, Avg. Displays hours:minutes after 1 hour. 24-hour Display (f off): shown in hours:minutes to maximum of 23:59. For setting the 24-hour clock, refer to Chapter 5. Secondary Display
MEM
Description
fMS88:88
HM
88:88
8.8.8.8
q1888
Memory Index Display (Model 189). Also used for dBm reference resistance.
q appears when you can use [ and ]
settings.
to increment or decrement
2-16
Getting Acquainted Using the Input Terminals
2
Using the Input Terminals
All functions except current use the and COM inputs. Current functions use the inputs shown below: · mA to 20 A. Use mA/µA and COM for inputs 400 mA. 5000.0 µA.
*
I or K function: Use A and COM inputs from 400 = or x function: Use mA/µA and COM for inputs
A
mA A
COM
V
·
If a test lead is plugged into the mA/µA or A terminal, but the rotary switch is not correctly set to one of the current measuring positions, the Input AlertTM beeper warns you by making a chirping sound and the primary display shows "LEAd5". This warning is intended to stop you from attempting to measure voltage, continuity, resistance, capacitance, or diode values when the leads are plugged into a current terminal. Figure 2-5 shows the input terminals.
tc014f.eps
Figure 2-5. Input Terminals
2-17
Model 187 & 189 Users Manual
Using Display Hold
Press Q to enter the Display Hold mode and freeze the present reading and its time stamp. New readings now appear in the secondary display. See Figure 2-6. To exit Display Hold mode, press Q again. Note The bar graph and secondary display may show different units in Capacitance and Ohms due to Autoranging. In the MIN MAX mode, Display Hold functions like a toggle, interrupting and resuming the MIN MAX operations. With Model 189, you cannot use Display Hold while logging data. Model 189 allows you to save the frozen reading to memory by pressing O R (SAVE).
AutoHOLD
tc040f.eps
Figure 2-6. Display Hold and AutoHOLD
2-18
Getting Acquainted Using AutoHOLD
2
Using AutoHOLD
WWarning
AutoHOLD mode does not capture unstable or noisy readings. Do not use AutoHOLD mode to determine that circuits are without power. To enter AutoHOLD, press OQ(AutoHOLD). AutoHOLD mode freezes the present reading and its time stamp. New readings now appear in the secondary display. See Figure 2-6. When the meter detects a new, stable reading (>4% change from last stable reading), it beeps and displays the new reading in the primary display. You can also force a primary display update by pressing Q. If you remove the test leads (open the input), the meter retains the last frozen primary display. You cannot use AutoHOLD when MIN MAX is active. With Model 189, you cannot initiate AutoHOLD while logging data, but you can initiate logging when AutoHOLD is active. To exit AutoHOLD mode, press O Q (AutoHOLD) again.
Using MIN MAX
The MIN MAX mode stores minimum (MIN) and maximum (MAX) input values. When the input goes below the stored minimum value or above the stored maximum value, the meter beeps and stores the new value. MIN MAX mode also calculates an average (AVG) of all readings taken since the mode was activated. Press M to enter the MIN MAX mode. The maximum (MAX) reading is displayed first. Each subsequent press of M steps through the minimum (MIN), average (AVG), and back to the maximum reading. In the MIN MAX mode, the secondary display continues to show the present measurement value. The time elapsed since the MIN MAX mode was entered is shown in the bottom right corner of each type of display. See Figure 2-7.
2-19
Model 187 & 189 Users Manual To exit MIN MAX mode, press O N (CANCEL) or turn the rotary switch to a different position. Also, MIN MAX mode turns off automatically when a flashing B (low battery condition) occurs. Note Minimum, maximum, and average values stored in the MIN MAX mode are lost when the meter is turned off. The MIN MAX mode can be used to capture intermittent readings, store maximum readings while you are away, or store readings while you are operating the equipment under test and cannot watch the meter. The average reading is useful for smoothing out unstable inputs, calculating power consumption, or estimating the percent of time a circuit is active. The MIN MAX mode is appropriate for storing signal events that last 50 ms or longer in most measurement functions. Signal events must be 500 ms or longer in the following functions: continuity, conductance, capacitance, temperature, Hz, duty cycle, and pulse width.
2-20
Getting Acquainted Using FAST MN MX
2
Using FAST MN MX
FAST MN MX can capture transient signal events as short as 250 µs, but with decreased accuracy; only 3-1/2 display digits are allowed. Activate FAST MN MX by pressing O M. As with regular MIN MAX, you can then press M to cycle through maximum, minimum, and average primary displays. The meter beeps for any new minimum or maximum value. Exit FAST MN MX by pressing ON (CANCEL) or by turning the rotary switch. A low battery condition (flashing B) disables FAST MN MX. In ac measurement functions, MAX and MIN values are peak values, AVG is the rms value. This provides the necessary information in one display for calculation of Crest Factor (peak/rms). Due to longer required response times, you cannot use FAST MN MX in the following functions: ohms, diode test, conductance, continuity, capacitance, temperature, ac over dc, ac+dc, Hz, duty cycle, and pulse width.
tc033f.eps
Figure 2-7. Min Max Avg
2-21
Model 187 & 189 Users Manual
Using HOLD with MIN MAX or FAST MN MX
You can enable the HOLD mode when in the MIN MAX mode is by pressing Q. No further minimum, maximum, or average updates occur while the HOLD mode is enabled. Exit HOLD mode by pressing Q a second time.
·
Press D a second time to enter the REL% mode and display the difference as ± 10 % of the reference reading. In REL%, e% appears on the display.
·
Press D a third time to exit the Relative Mode.
Using Relative Mode (REL)
Selecting Relative mode (D) causes the meter to zero the display and store the present reading as a reference for subsequent measurements. · Press D once to select the Relative Mode. (The meter enters manual range when you enter the Relative Mode.) The reference appears in the secondary display. The difference between the reference and a new measurement appears in the primary display. See Figure 2-8.
tc039f.eps
Figure 2-8. Relative Mode
2-22
Chapter 3
Making Measurements
Introduction
Chapter 3 explains how to make measurements. Most measurement functions can be selected by using the rotary switch. White letters or symbols identify primary functions; blue letters or symbols identify alternative functions. Press the blue button to access these alternate functions. Frequency-related functions can be selected (Hz, duty cycle, and pulse width) when the rotary switch is in any volts or amps position. Ranges available in volts functions are: ·
\$
5.0000 V, 50.000 V, 500.00 V, 1000.0 V ·
,m
50.000 mV, 500.00 mV, and 5000.0 mV Readings in the 5000.0 mV range overload (0L) near 3000 mV ac or dc. The 5000.0 mV range overlaps the 5.0000 V range to provide direct reading display for Fluke accessories that have a millivolt output with limits scaled by 1000. For example, the Fluke 80i-1000 Current Clamp provides 1 mV ac per amp measured up to 1000 amps.
Measuring Voltage
Voltage is the difference in electrical potential between two points. The polarity of ac (alternating current) voltage varies over time, while the polarity of dc (direct current) voltage is constant over time.
3-1
Model 187 & 189 Users Manual When measuring voltage, the meter acts like a 10 M (10,000,000 ) impedance in parallel with the circuit. This loading effect can cause measurement errors in highimpedance circuits. In most cases, the error is negligible (0.1% or less) if the circuit impedance is 10 k (10,000 ) or less.
189
LOGGING MULTIMETER
Measuring AC Voltage
The meter presents ac voltage values as rms (root mean square) readings. The rms value is the equivalent dc voltage that would produce the same amount of heat in a resistance as the measured voltage. Your meter features true rms readings, which are accurate for sinewaves and other wave forms (with no dc offset) such as square waves, triangle waves, and staircase waves. For ac with . dc offset, use
AutoHOLD FAST MN MX LOGGING YES
HOLD
MIN MAX
CANCEL
REL
SAVE NO
Hz % ms
SETUP
RANGE
nS
ac+dc
mV
C
F
ac+dc
V
A mA A A mA
ac+dc ac+dc
$
dB
V
dB
mV V
OFF
VIEW
CLEAR MEM
dB
A
Switch Box
TEMPERATURE
Set up the meter to measure ac volts as shown in Figure 3-1. All pushbutton features are available in this function. The blue button ( %) accesses decibel dBm or dBV) measurements, discussed next in this chapter.
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
ach001f.eps
Figure 3-1. AC Voltage Measurement
3-2
Making Measurements Measuring Voltage
3
dB Measurements in AC Volts Functions
The two ac volts functions allow you to display readings as deviations in dB (decibels) above or below an established level. Set up dB measurements with the following procedure: 1. 2. Make an ac volts measurement to be used as a reference point. Press % to select dB. The dBm (or dBV) value appears in the primary display and the ac volts reading appears in the secondary display. A typical dB display appears in Figure 3-2. Press % again to switch the ac volts and dB readings. Press % a third time to turn dB off.
tc032f.eps
Figure 3-2. dBm Display Normally, dB is measured as dBm, which is a measure of decibels relative to 1 milliwatt. The meter assumes a resistance of 600 in making this calculation. This resistance can be set for any value from 1 to 1999 , using the meter's setup capabilities (see Chapter 5.) When set to other than 600 the dBm reference resistance appears in the Index Display. (See Figure 2-4, item 17.) Note If dBm is displayed, check that the reference resistance value closely matches the impedance of the system being measured.
3.
3-3
Model 187 & 189 Users Manual dB is calculated with the following formula:
Measuring DC Voltage
Set up the meter for dc voltage measurement as shown in Figure 3-4. All pushbutton features are available for a standard dc volts reading.
Vx dB = 20 * log10 Vr
· For dBm, Vr is the voltage across the reference resistance at 1 mW. For example, Vr would be 0.7746 V with a 600 reference resistance. For dBV, the reference voltage (Vr) is 1 V.
Both AC and DC Voltage Measurements
When a dc volts function is selected, the meter can display ac and dc components of a signal separately or the combined ac + dc (rms) value. To select separate ac and dc signal components: · Press % once to display ac voltage in the primary display and dc voltage in the secondary display (ac over dc). · Press % a second time to reverse the displays (dc over ac). · Press % a third time to display the ac + dc rms value in the primary display. (FAST MN MX is unavailable in this state.) · Press % a fourth time to return to the normal dc volts display. Figure 3-3 shows some typical displays.
·
3-4
Making Measurements Measuring Voltage
3
AC over DC
DC over AC
AC + DC
tc024f.eps
Figure 3-3. AC and DC Display When the meter shows ac over dc or dc over ac, the following other pushbutton functions are not available: · · · · · · AutoHOLD ( O Q) MIN MAX ( M) FAST MN MX ( O M) Hz ( N) Relative ( D) LOGGING (O D)
3-5
Model 187 & 189 Users Manual
Measuring Resistance
189
LOGGING MULTIMETER
Caution To avoid possible damage to the meter or to the equipment under test, disconnect circuit power and discharge all high-voltage capacitors before measuring resistance. Resistance is an opposition to current flow. The unit of resistance is the ohm (). The meter measures resistance by sending a small current through the circuit. The meter's resistance ranges are 500.00 , 5.0000 k, 50.000 k, 500.00 k, 5.0000 M, 30.000 M, and 500.0 M. To measure resistance, set up the meter as shown in Figure 3-5. All pushbutton functions are available with resistance measurements. The blue key cycles to continuity and conductance measurement, which are described later in this chapter. Note In the Ohms Mode, a negative sign (-) on the display indicates the presence of voltage. This will cause reading errors.
AutoHOLD
FAST MN MX
LOGGING
YES
HOLD
MIN MAX
CANCEL
REL
SAVE NO
Hz % ms
SETUP
RANGE
nS
ac+dc
V
dB
ac+dc
mV
C
F
ac+dc
V
A mA A A mA
ac+dc ac+dc
mV V
OFF
VIEW
CLEAR MEM
dB
A
TEMPERATURE
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
+
ach002f.eps
Figure 3-4. DC Voltage Measurement
3-6
Making Measurements Measuring Resistance
3
In-Circuit Resistance Measurements Circuit Power
Isolating a Potentiometer
OFF
1
189
LOGGING MULTIMETER
3 2 Disconnect
1
AutoHOLD FAST MN MX LOGGING YES
2 3
HOLD
MIN MAX
CANCEL
REL
SAVE NO
Hz % ms
SETUP
RANGE
nS
nS
ac+dc
mV
C
F
Isolating a Resistor
A mA A A mA
ac+dc ac+dc
ac+dc
V
dB
mV V
OFF
VIEW
CLEAR MEM
dB
A
TEMPERATURE
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
Disconnect
ach004f.eps
Figure 3-5. Resistance Measurement
3-7
Model 187 & 189 Users Manual
Keep the following in mind when measuring resistance: · Because the meter's test current flows through all possible paths between the probe tips, the measured value of a resistor in a circuit is often different from the resistor's rated value. The test leads can add 0.1 to 0.2 of error to resistance measurements. To test the leads, touch the probe tips together and read the resistance of the leads. If necessary, you can press D to automatically subtract this value.
Testing for Continuity
Caution To avoid possible damage to the meter or to the equipment under test, disconnect circuit power and discharge all high-voltage capacitors before testing for continuity. Continuity is the presence of a complete path for current flow. The continuity test features a beeper that sounds if a circuit is complete. The beeper allows you to perform quick continuity tests without having to watch the display. The continuity function detects intermittent opens and shorts lasting as little as 1 millisecond (0.001 second). These brief contacts cause the meter to emit a short beep. To select continuity, turn the rotary switch to resistance position, then press the blue button once. The continuity symbol (~) appears in the display. Continuity uses manual ranging only; autoranging is not available. Refer to Figure 3-6 for continuity testing setup instructions.
·
The resistance function can produce enough voltage to forward-bias silicon diode or transistor junctions, causing them to conduct. To avoid this, do not use the 30 M or 500 M ranges for in-circuit resistance measurements.
3-8
Making Measurements Using Conductance for High Resistance Tests Continuity testing provides you with both a visual indication of the state encountered (usually near 0 resistance for a short or OL for an open) and an audible beep when the input is low. In continuity, a short means a measured value less than 5% of full scale. You can raise this threshold by manually selecting a higher range. You can select whether the beeper comes on for open or short conditions, as follows: · · Press [ to enable the beeper for opens. Press ] to enable the beeper for shorts.
3
Using Conductance for High Resistance Tests
Conductance, the inverse of resistance, is the ability of a circuit to pass current. High values of conductance correspond to low values of resistance. The unit of conductance is the Siemens (S). The meter's 50 nS range measures conductance in nanosiemens (1 nS = 0.000000001 Siemens). Because such small amounts of conductance correspond to extremely high resistance, the nS range lets you determine the resistance of components up to 100,000 M, or 100,000,000,000 (1 nS = 1,000 M). To measure conductance, set up the meter as shown in Figure 3-7; then press the blue key until the nS indicator appears on the display. With conductance measurements, the following pushbutton operations cannot be used: · · · Frequency ( N) FAST MN MX ( O M) Manual ranging ( R)
The Hz ( N) and FAST MN MX ( O M) functions are not available when continuity is selected. All other pushbutton functions are available. The blue key cycles among resistance, continuity, and conductance.
3-9
Model 187 & 189 Users Manual
For in-circuit tests, turn circuit power off.
Press for beep on open
189
LOGGING MULTIMETER
2 Press for beep on short
AutoHOLD
189
LOGGING MULTIMETER
AutoHOLD
FAST MN MX
LOGGING
YES
FAST MN MX
LOGGING
YES
HOLD
MIN MAX
CANCEL
REL
SAVE NO
HOLD
MIN MAX
CANCEL
REL
SAVE NO
nS
SETUP
Hz % ms
SETUP
RANGE
Hz % ms
RANGE
nS
nS
ac+dc
mV
C
F
ac+dc
mV
ac+dc
V
A mA A A mA
ac+dc ac+dc
dB
mV V
OFF
VIEW
CLEAR MEM
dB
A
1 Press to select "
OFF (open)
."
C
F
ac+dc
V
A mA A A mA
ac+dc ac+dc
OFF (open)
dB
mV V
OFF
VIEW
CLEAR MEM
dB
A
TEMPERATURE
TEMPERATURE
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
ON (closed)
Figure 3-6. Continuity Test
ON (closed)
ach003f.eps
3-10
Making Measurements Using Conductance for High Resistance Tests
3
The following are some tips for measuring conductance: · High-resistance readings are susceptible to electrical noise. Use averaging to smooth out most noisy readings; press M until AVG appears in the display. There is normally a residual conductance reading with the test leads open. To ensure accurate readings, press D with the test leads open to subtract the residual value.
189
LOGGING MULTIMETER
·
nS
AutoHOLD FAST MN MX LOGGING YES
HOLD
MIN MAX
CANCEL
REL
SAVE NO
Hz % ms
SETUP
RANGE
nS
ac+dc
mV
C
F
ac+dc
V
A mA A A mA
ac+dc ac+dc
Press twice to select nS.
dB
mV V
OFF
VIEW
CLEAR MEM
dB
A
TEMPERATURE
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
ach023f.eps
Figure 3-7. Conductance Measurement
3-11
Model 187 & 189 Users Manual
Measuring Capacitance
Caution To avoid possible damage to the meter or to the equipment under test, disconnect circuit power and discharge all high-voltage capacitors before measuring capacitance. Use the dc voltage function to confirm that the capacitor is discharged. Capacitance is the ability of a component to store an electrical charge. The unit of capacitance is the farad (F). Most capacitors are in the nanofarad (nF) to microfarad (µF) range. The meter measures capacitance by charging the capacitor with a known current for a known period of time, measuring the resulting voltage, then calculating the capacitance. Capacitors larger than 100 µF take several seconds to charge. The capacitor charge can be up to 3 V. The meter's capacitance ranges are 1 nF, 10 nF, 100 nF, 1 µF, 10 µF, 100 µF, 1 mF, 10 mF, and 50 mF.
To measure capacitance, set up the meter as shown in Figure 3-8. The blue key toggles the selection between capacitance and diode test. While measuring capacitance, the following pushbutton functions are not available: · · Frequency ( N) FAST MN MX ( O M)
The following are some tips for measuring capacitance: · · To speed up measurements of similar values, press R to manually select the proper range. To improve the measurement accuracy of small value capacitors, press D with the test leads open to subtract the residual capacitance of the meter and leads.
3-12
Making Measurements Testing Diodes
3
Testing Diodes
Caution
189
LOGGING MULTIMETER
AutoHOLD
FAST MN MX
LOGGING
YES
To avoid possible damage to the meter or to the equipment under test, disconnect circuit power and discharge all high-voltage capacitors before testing diodes. Use the diode test to check diodes, transistors, silicon controlled rectifiers (SCRs), and other semiconductor devices. The test sends a current through a semiconductor junction, then measures the junction's voltage drop. A typical junction drops 0.5 V to 0.8 V. In diode test, the beeper is active. It beeps briefly for a normal junction and is on continuously if a short is detected. To test a diode out of a circuit, set up the meter as shown in Figure 3-9.
+ + + + + + + +
HOLD
MIN MAX
CANCEL
REL
SAVE NO
Hz % ms
SETUP
RANGE
nS
ac+dc
mV
C
F
ac+dc
V
A mA A A mA
ac+dc ac+dc
dB
mV V
OFF
VIEW
CLEAR MEM
dB
A
TEMPERATURE
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
+
ach005f.eps
In a circuit, a similar diode should still indicate a forwardbias reading of 0.5 V to 0.8 V; however, the reverse-bias reading can vary depending on the resistance of other pathways between the probe tips. The blue key toggles between diode test and capacitance. Since diode test uses a fixed range, R cannot be used.
Figure 3-8. Capacitance Measurement
3-13
Model 187 & 189 Users Manual
Typical Reading
189
LOGGING MULTIMETER
189
LOGGING MULTIMETER
AutoHOLD
FAST MN MX
LOGGING
YES
AutoHOLD
FAST MN MX
LOGGING
YES
HOLD
MIN MAX
CANCEL
REL
SAVE NO
HOLD
MIN MAX
CANCEL
REL
SAVE NO
Hz % ms
SETUP
RANGE
SETUP
Hz % ms
RANGE
nS
ac+dc
mV
C
F
Forward Bias
ac+dc
nS
mV
C
F
Reverse Bias
A mA A A mA
ac+dc ac+dc
ac+dc
V
A mA A A mA
ac+dc ac+dc
dB
mV V
OFF
VIEW
CLEAR MEM
dB
A
Press for Diode Test
+
ac+dc
V
dB
mV V
OFF
VIEW
CLEAR MEM
+
dB
A
TEMPERATURE
TEMPERATURE
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
ach006f.eps
Figure 3-9. Diode Test
3-14
Making Measurements Measuring Temperature
3
Measuring Temperature
To measure temperature, set up the meter as shown in Figure 3-10. The meter begins temperature measurement in the degree units last used (Celsius °C or Fahrenheit °F). Once you have selected the temperature function, you can change units by pressing the blue button. The meter remembers the units selected until they are changed. The primary display shows either the temperature or the message `0PEn' (for an open thermocouple condition). Shorting the input will display the temperature at the meter terminals. The secondary display shows any non-zero temperature offset. This offset is established as a calibrating value during setup. Refer to Chapter 5 for additional information. The following pushbuttons cannot be used when taking temperature measurements: · · · Frequency ( N) FAST MN MX ( O M) Ranging ( R)
80AK 80PK-1 Type K Thermocouple Probe Vent or Pipe
189
LOGGING MULTIMETER
AutoHOLD
FAST MN MX
LOGGING
YES
F
C
HOLD
MIN MAX
CANCEL
REL
SAVE NO
Hz % ms
SETUP
RANGE
nS
ac+dc
mV
C
F
C
A mA A A mA
ac+dc ac+dc
F
ac+dc
V
dB
mV V
OFF
VIEW
CLEAR MEM
dB
A
TEMPERATURE
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
WWarning
To avoid the potential for fire or electrical shock, do not connect the thermocouples to electrically live circuits.
ach010f.eps
Figure 3-10. Temperature Measurement
3-15
Model 187 & 189 Users Manual
Measuring Current
WWarning
Never attempt an in-circuit current measurement where the open-circuit potential to earth is greater than 1000 V. You may damage the meter or be injured if the fuse blows during such a measurement. Caution To avoid possible damage to the meter or to the equipment under test, check the meter's fuses before measuring current. Use the proper terminals, function, and range for your measurement. Never place the probes across (in parallel with) any circuit or component when the leads are plugged into the current terminals. Current is the flow of electrons through a conductor. To measure current, you must open the circuit under test, then place the meter in series with the circuit.
To measure ac or dc current, proceed as follows: 1. 2. Turn off power to the circuit. Discharge all highvoltage capacitors. Insert the black lead into the COM terminal. Insert the red lead in an input appropriate for the measurement range as shown in Table 3-1. Note To avoid blowing the meter's 440 mA fuse, use the mA/µA terminal only if you are sure the current is less than 400 mA. Table 3-1. Current Measurement Rotary Switch Input Ranges 5.0000 A 10.000 A (reading flashes at 10 A, overloads (0L) at 20 A) 50.000 mA 500.00 mA 500.00 µA 5000.0 µA
I or K
! #
= or x
#
3-16
Making Measurements Measuring Current 3. If you are using the A terminal, set the rotary switch to mA/A. If you are using the mA/µA terminal, set the rotary switch to µA for currents below 5000 µA (5 mA), or mA/A for currents above 5000 µA. Open the circuit path to be tested. Touch the red probe to the more positive side of the break; touch the black probe to the more negative side of the break. Reversing the leads will produce a negative reading, but will not damage the meter. Turn on power to the circuit; then read the display. Be sure to note the unit given at the right side of the display (µA, mA, or A). Turn off power to the circuit and discharge all highvoltage capacitors. Remove the meter and restore the circuit to normal operation.
3
Input AlertTM Feature
If a test lead is plugged into the mA/µA or A terminal, but the rotary switch is not correctly set to one of the current measuring positions, the beeper warns you by making a chirping sound and the display shows "LEAd5". This Input Alert warning is intended to stop you from attempting to measure voltage, continuity, resistance, capacitance, or diode values when the leads are plugged into a current terminal. Placing the probes across (in parallel with) a powered circuit when a lead is plugged into a current terminal can damage the circuit you are testing and blow the meter's fuse. This can happen because the resistance through the meter's current terminals is very low, so the meter acts like a short circuit. Note The beeper may sound in the presence of high electical noise, such as that found near Pulse Width Modulation (PWM) motor drives.
4.
5.
6.
3-17
Model 187 & 189 Users Manual The following are some tips for measuring current: · If the display shows LEAd5 and you are sure the meter is set up correctly, test the meter's fuses as described under "Testing the Fuses" in Chapter 6. A current meter drops a small voltage across itself, which might affect circuit operation. You can calculate this burden voltage using the values listed in Chapter 7 under Burden Voltage (A, mA, µA).
Measuring AC Current
To measure ac current, set up the meter as shown in Figure 3-11. The blue pushbutton cannot be used with ac current measurement. All other pushbutton features can be used.
·
3-18
Making Measurements Measuring Current
3
189
LOGGING MULTIMETER
189
LOGGING MULTIMETER
189
LOGGING MULTIMETER
AutoHOLD
FAST MN MX
LOGGING
YES
AutoHOLD
FAST MN MX
LOGGING
YES
AutoHOLD
FAST MN MX
LOGGING
YES
HOLD
MIN MAX
CANCEL
REL
SAVE NO
HOLD
MIN MAX
CANCEL
REL
SAVE NO
HOLD
MIN MAX
CANCEL
REL
SAVE NO
Hz % ms
SETUP
RANGE
SETUP
Hz % ms
RANGE
SETUP
Hz % ms
RANGE
nS
nS
nS
ac+dc
mV
C
F
ac+dc
V
A mA A A mA
ac+dc ac+dc
A mA
dB
ac+dc
mV
C
F
ac+dc
V
A mA A A mA
ac+dc ac+dc
A mA
dB
ac+dc
mV
C
F
ac+dc
V
A mA A A mA
ac+dc ac+dc
dB
mV V
OFF
VIEW
CLEAR MEM
mV V
OFF
VIEW
CLEAR MEM
mV V
OFF
VIEW
CLEAR MEM
A
dB
dB
dB
A
A
A
TEMPERATURE
TEMPERATURE
TEMPERATURE
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
A
10A MAX FUSED
mA A
400mA FUSED
COM
CAT 1000V
V
ach008f.eps
Figure 3-11. AC Current Measurement
3-19
Model 187 & 189 Users Manual
Measuring DC Current
To measure dc current, set up the meter as shown in Figure 3-12. You can view separate dc and ac amps signal components. · Press % once to display ac current in the pr