Digi-Sense 20250-57 User manual

THE STANDARD IN PRECISION MEASUREMENT
User Manual
Autoranging Clamp Meters
with NIST-Traceable Calibration
Models 20250-57 (1000 A AC),
20250-58 (1000 A AC/DC, True RMS)
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Introduction
The Digi-Sense Autoranging Clamp Meters (1000 A AC
Model 20250-57; 1000 A AC/DC True RMS Model 20250-58)
offer all the basic features needed for measurement. The
double-molded plastic housing and jaw are designed for
use in tight places. A large backlit display provides easy-to-
read measurements. The instruments are fully tested and
calibrated to NIST-traceable standards. Careful use of the
meter will provide years of reliable service.
Safety
International Safety Symbols
This symbol, adjacent to another symbol or terminal,
indicates the user must refer to the manual for
further information.
This symbol, adjacent to a terminal, indicates that,
under normal use, hazardous voltages may be
present
Double insulation
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SAFETY NOTES
• Do not exceed the maximum allowable input range of any
function.
• Do not apply voltage to meter when resistance function is
selected.
• Set the function switch OFF when the meter is not in use.
WARNINGS
• Set rotary function switch to the appropriate position
before measuring.
• When measuring volts, do not switch to current/resistance
modes.
• When changing ranges using the rotary function switch,
always disconnect the test leads from the circuit under
test.
• Do not exceed the maximum rated input limits:
Input Limits
Function Maximum Input,
Model 20250-57 Maximum Input, Model 20250-58
A 1000 A AC 1000 A AC/DC
V 600 V AC/DC 600 V AC/DC
Frequency, Duty
cycle, Resistance,
Diode, Continuity,
Capacitance Test
250 V AC/DC 250 V AC/DC
Temperature (°C/°F) — 60 V DC, 24 V AC
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CAUTIONS
• Improper use of this meter can cause damage, shock,
injury or death. Read and understand this user manual
before operating the meter.
• Always remove the test leads before replacing the
battery.
• Inspect the condition of the test leads and the meter
itself for any damage before operating the meter. Repair
or replace any damage before use.
• Use great care when making measurements if the
voltages are greater than 25 VAC rms or 35 VDC. These
voltages are considered a shock hazard.
• Remove the battery if the meter is to be stored for long
periods.
• Always discharge capacitors and remove power from
the device under test before performing Diode,
Resistance, or Continuity tests.
• Voltage checks on electrical outlets can be difcult and
misleading because of the uncertainty of connection to
the recessed electrical contacts. Other means should be
used to ensure that the terminals are not "live".
• If the equipment is used in a manner not specied by the
manufacturer, the protection provided by the equipment
may be impaired.
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Unpacking
Check individual parts against the list of items below. If
anything is missing or damaged, please contact your
instrument supplier immediately.
1. Meter
2. Test leads
3. Temperature probe (model 20250-58 only)
4. Carrying case
5. 9 V battery
6. User manual
7. NIST-traceable calibration report with data
Key Features
1. Durable double-molded housing
2. 13⁄16" (30 mm) jaw opening
3. CAT III 600 V safety rating
4. Electronic overload protection
5. Autoranging with auto power-off
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Meter Description (Model 20250-57)
1. Current clamp
2. Clamp trigger
3. Data HOLD and Backlight button
4. MODE select button
5. RANGE select button
6. LCD
7. COM input jack
8. Rotary function switch
9. Hz% Hold button
10. Max/Min button
11. V Ω •))) Hz jack
12. Battery compartment (on rear)
Meter Description (Model 20250-58)
1. Current clamp
2. Clamp trigger
3. Data HOLD and Backlight button
4. MODE select button
5. RANGE select button
6. LCD
7. COM input jack
8. Rotary function switch
9. DC ZERO button
10. Max/Min button
11. V Ω •))) CAP Hz Temp jack
12. Battery compartment (on rear)
60A
600A
A
1
2
9
4
3
6
5
8
7
600A
A


A


60A
A
A








6
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Display Layout
1. AC DC AC (alternating current) and
DC (direct current)
2. –Minus sign
3. 8.8.8.8 6000 count (0 to 5999) measurement
reading with 61-segment analog
bar graph
4. AUTO Autorange mode
5. MAX MIN Max and Min readings
6. HOLD Data HOLD mode
7. Diode test mode
8. •))) Audible continuity
9. µ,m,V,A,K, Units of measure list (20250-57);
M,Ω;
°C,°F, µ,m,V, Units of measure list (20250-58)
A,K,M,Ω
60A
600A
A
1
2
9
4
3
6
5
8
7
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Setup and Operation
Note: Read and understand all warning and precaution
statements listed in the safety section of this operation
manual prior to using this meter. Set the rotary function
switch to the OFF position when the meter is not in use.
AC and AC/DC Current Measurements
WARNING: Ensure that the test leads are disconnected
from the meter before making current clamp measure-
ments.
1. Set the Function switch
to the 1000A or 600A
or 60A range.
2. For model 20250-58
only, select AC or DC
by pressing the MODE
button.
3. If the range of the
measured is unknown,
select the higher range
rst then move to the
lower range as neces-
sary.
4. Press the trigger to open jaw. Fully enclose one conduc-
tor to be measured (see diagram above). The LCD will
display the reading.
5. In DCA mode, to ensure the reading is correct, press
the DC ZERO button to clear the reading on the LCD
before measurement. The LCD will display the reading
(model 20250-58 only).
！ ！
DC DC
AC AC
Ω Ω
CAP CA P
n
n
n
n
A A
+ +
. .
. .
No Yes
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AC/DC Voltage Measurements
1. Insert the black test lead into the negative COM terminal
and the red test lead into the positive V terminal.
2. Set the rotary function switch to the Vposition.
3. For model 20250-58, select AC or DC by pressing the
MODE button.
4. Connect the test leads in parallel to the circuit under test.
5. Read the voltage measurement in the display.
Resistance and Continuity Measurements
1. Insert the black test lead into the negative COM terminal
and the red test lead into the positive terminal.
2. Set the rotary function switch to the Ω•))) position.
3. Use the multifunction MODE button to select resistance.
4. Touch the test probe tips across the circuit or component
under test. It is best to disconnect one side of the device
under test so the rest of the circuit will not interfere with
the resistance reading.
5. For Resistance tests, read the resistance value in the
display.
6. For Continuity tests, if resistance is <100 Ω, a tone will
sound.
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Diode and Continuity Measurements
1. Insert the black test lead banana plug into the negative
COM jack and the red test lead banana plug into the
positive diode jack.
2. Turn the rotary function switch to the •))) position.
3. Press the MODE button until “ “ appears in the
display.
4. Touch the test probes to the diode under test. Forward
voltage will indicate 0.4 V to 0.7 V. Reverse voltage will
indicate “OL”. Shorted devices will indicate near 0 mV and
an open device will indicate “OL” in both polarities.
Capacitance Measurements
WARNING: To avoid electric shock, disconnect power to the
unit under test and discharge all capacitors before taking
any capacitance measurements. Remove the batteries and
unplug the line cords.
1. Set the rotary function switch to the Ω•))) CAP
position.
2. Insert the black test lead banana plug into the negative
COM jack and the red test lead banana plug into the
positive V jack.
3. Touch the test leads to the capacitor to be tested.
4. Read the capacitance value on the display.
Red Black Black Red
Forward test Reverse test
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Frequency or % Duty Cycle Measurements
For Model 0250-57:
1. Set the rotary function switch to the Hz% position.
2. Press the Hz% button to indicate “Hz” in the display.
3. Insert the black lead banana plug into the negative COM
jack and the red test lead banana plug into the positive
Hz jack.
4. Touch the test probe tips to the circuit under test.
5. Press the Hz% button again to indicate “%” on the
display. Read the % of duty cycle on the display.
For Model 20250-58:
1. Set the rotary function switch to the Hz% position.
2. Insert the black lead banana plug into the negative COM
jack and the red test lead banana plug into the positive
Hz jack.
3. Press the MODE button to select “Hz” or “%”.
4. Touch the test probe tips to the circuit under test.
5. Read the frequency or % of duty cycle on the display.
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Temperature Measurements (Model 20250-58 only)
WARNING: To avoid electric shock, disconnect both
test probes from any source of voltage before making a
temperature measurement.
1. Set the function switch to TEMP.
2. Insert the temperature probe into the negative COM and
the V jacks, making sure to observe the correct polarity.
3. Select °C or °F units by pressing the MODE button.
4. Touch the temperature probe head to the part whose
temperature you wish to measure. Keep the probe
touching the part under test until the reading stabilizes
(about 30 seconds).
5. Read the temperature in the display. The digital reading
will indicate the proper decimal point and value.
WARNING: To avoid electric shock, be sure the
thermocouple has been removed before changing to
another measurement function.
MODE Button
To select DC/ACV, OHM/Diode/Continuity/CAP
(°C or °F model 20250-58 only).
Data HOLD and Backlight Button
To “freeze” a reading on the screen, press the data HOLD
button. While data HOLD is active, the “HOLD” display
icon appears on the LCD. Press the HOLD button again to
resume normal operation.
Note: The HOLD feature will activate when the Backlight
is turned on.
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The backlight function illuminates the display and is used
when the ambient light to too low to permit viewing of the
displayed readings. Press the HOLD/backlight button for
one second to turn the backlight on and press the button a
second time to turn the backlight off.
RANGE Button
When the meter is rst turned on, it defaults to Auto
Ranging. This automatically selects the best range for the
measurements being made and is generally the optimal
mode for most measurements. For measurement
situations requiring that a range be manually selected,
perform the following:
1. Press the RANGE button. The “Auto Range” display
indicator will turn off, and the “Manual Range” display
indicator will turn on.
2. Press the RANGE button again to step through the
available ranges until you select the range you want.
3. Press and hold the RANGE button for 2 seconds to exit
the Manual Ranging mode and return to Auto Ranging.
Note: Manual Ranging does not function in the AC Current,
Diode, and Continuity check functions.
Automatic Power-Off
To conserve battery life, the meter automatically turns off
after 30 minutes of nonuse.
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Model 20250-57 Model 20250-58
Function Range &
Resolution Accuracy (% of reading) Range & Resolution Accuracy (% of reading)
AC Current
60.00 AAC ±(2.5% + 10 digits) 60.00 AAC
(True RMS) ±(3.0% + 10 digits)
600.0 AAC ±(2.0 % + 5 digits)
600.0 AAC
(True RMS) ±(3.0 % + 8 digits)
1000 AAC 1000 AAC
(True RMS) ±(3.0 % + 5 digits)
DC Current
— — 60.00 ADC ±(2.8% + 10 digits)
— — 600.0 ADC ±(2.8 % + 8digits)
— — 1000 ADC ±(3.0 % + 5 digits)
DC Voltage
600.0 mVDC ±(0.8% + 3 digits) 600.0 mVDC ±(0.8% + 3 digits)
6.000 VDC
±(1.5% + 3 digits)
6.000 VDC
±(1.5% + 3 digits)60.00 VDC 60.00 VDC
600.0 VDC 600.0 VDC
— — 800 VDC ±(2.0% + 3 digits)
1000 VDC ±(2.0% + 3 digits) — —
AC Voltage
— — 600.0 mVAC
(True RMS) ±(0.8% + 20 digits)
6.000 VAC ±(1.5% + 5 digits) 6.000 VAC
(True RMS)
±(1.8% + 5 digits)60.00 VAC
±(2.0% + 5 digits)
60.00 VAC
(True RMS)
600.0 VAC 600.0 VAC
(True RMS)
750 VAC ±(2.0% + 5 digits) 750 VAC
(True RMS) ±(2.5% + 5 digits)
Resistance
600.0 Ω±(1.0% + 4 digits) 600.0 Ω±(1.0% + 4 digits)
6.000 KΩ
±(1.5% + 2 digits)
6.000 KΩ
±(1.5% + 2 digits)60.00 KΩ60.00 KΩ
600.0 KΩ600.0 KΩ
6.000 MΩ±(2.5% + 3 digits) 6.000 MΩ±(2.5% + 3 digits)
Note: No autoranging in 600 mV AC voltage range (model 20250-58).
Specifications
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Model 20250-57 Model 20250-58
Function Range &
Resolution Accuracy (% of reading) Range & Resolution Accuracy (% of reading)
AC Current
60.00 AAC ±(2.5% + 10 digits) 60.00 AAC
(True RMS) ±(3.0% + 10 digits)
600.0 AAC ±(2.0 % + 5 digits)
600.0 AAC
(True RMS) ±(3.0 % + 8 digits)
1000 AAC 1000 AAC
(True RMS) ±(3.0 % + 5 digits)
DC Current
— — 60.00 ADC ±(2.8% + 10 digits)
— — 600.0 ADC ±(2.8 % + 8digits)
— — 1000 ADC ±(3.0 % + 5 digits)
DC Voltage
600.0 mVDC ±(0.8% + 3 digits) 600.0 mVDC ±(0.8% + 3 digits)
6.000 VDC
±(1.5% + 3 digits)
6.000 VDC
±(1.5% + 3 digits)60.00 VDC 60.00 VDC
600.0 VDC 600.0 VDC
— — 800 VDC ±(2.0% + 3 digits)
1000 VDC ±(2.0% + 3 digits) — —
AC Voltage
— — 600.0 mVAC
(True RMS) ±(0.8% + 20 digits)
6.000 VAC ±(1.5% + 5 digits) 6.000 VAC
(True RMS)
±(1.8% + 5 digits)60.00 VAC
±(2.0% + 5 digits)
60.00 VAC
(True RMS)
600.0 VAC 600.0 VAC
(True RMS)
750 VAC ±(2.0% + 5 digits) 750 VAC
(True RMS) ±(2.5% + 5 digits)
Resistance
600.0 Ω±(1.0% + 4 digits) 600.0 Ω±(1.0% + 4 digits)
6.000 KΩ
±(1.5% + 2 digits)
6.000 KΩ
±(1.5% + 2 digits)60.00 KΩ60.00 KΩ
600.0 KΩ600.0 KΩ
6.000 MΩ±(2.5% + 3 digits) 6.000 MΩ±(2.5% + 3 digits)
Model 20250-57 Model 20250-58
Function Range &
Resolution Accuracy (% of reading) Range & Resolution Accuracy (% of reading)
Capacitance
40.00 nF ±(3.0% reading
+ 50 digits) 40.00 nF ±(5.0% reading + 100 digits)
400.0 nF ±(3.5% reading
+ 10 digits)
400.0 nF ±(3.0% reading
+ 5 digits)
4.000 μF 4.000 μF ±(3.5% reading
+ 5 digits)
40.00 μF 40.00 μF
— — 100.0 μF ±(5.0% reading
+ 5 digits)
400.0 μF ±(5.0% reading
+ 5 digits)
— —
4000 μF — —
Frequency
9.999 Hz ±(1.2% reading
+ 2 digits)
Sensitivity:
9 to 1000 kHz:
10 Vrms min.
1000 kHz to 10 MHz:
20 Vrms min.
@ 20% to 80% duty
cycle
9.999 Hz
±(1.2% reading
+ 2 digits)
Sensitivity:
10 Vrms min.
99.99 Hz 99.99 Hz
999.9 Hz 999.9 Hz
9.999 kHz 9.999 kHz
99.99 kHz 99.99 kHz
999.9 kHz 999.9 kHz
10 MHz 10 MHz
Duty cycle
5.0 to 94.9% ±(1.2% reading
+ 2 digits) 0.5 to 99.0% ±(1.2% reading + 2 digits)
Pulse width: 100 μs to 100 ms;
Frequency: 30 Hz to 15 kHz Pulse width: 100 μs to 100 ms; Frequency: 5.000 Hz to 100.0 kHz
Temperature,
type K (probe
accuracy not
included)
— — –20 to 1000°C ±(3.0% reading
+ 5°C)
— — –4 to 1832°F ±(3.0% reading
+ 7°F)
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Clamp size Opening 13⁄16" (30 mm) approximately
Diode test Test current of 0.3 mA typical;
Open circuit voltage 1.5V DC typical
Continuity Threshold <30 Ω(20250-57), <100 Ω
check (20250-58), Test current <1 mA 
Low-battery “ ” is displayed
indication
Overrange “ OL” is displayed
indication
Measurement 2 per second, nominal
rate
Input 7.8 MΩ(VDC and VAC)
impedance
Display 6000 counts LCD
AC Current 50–60Hz (AAC) (20250-57),
50–60Hz (AAC TRMS) (20250-58)
AC Voltage 50–60Hz (VAC) (20250-57),
bandwidth 50–60Hz (VAC TRMS) (20250-58)
Operating 14 to 122°F (–10 to 50°C)
temperature
Storage –14 to 140°F (–30 to 60°C)
temperature
Operating 90% (0 to 30°C); 75% (30 to 40°C);
humidity 45% (40 to 50°C)
Specifications (continued)
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Operating 9842 ft (3000 meters),
altitude Storage 32,808 ft (10,000 meters)
Overvoltage Category III 600 V
Battery One 9 V battery
Auto power-off 30 minutes approximately
Weight 7.1 oz (200 g) model 20250-57;
10.7 oz (303 g) model 20250-58
Dimensions 87⁄8" x 33⁄16" x 111⁄16" (22.6 x 8 x 4.3 cm)
Safety For indoor use and in accordance with
Overvoltage Category II, Pollution
Degree 2. Category II includes local
level, appliance, portable equipment,
etc., with transient overvoltages less
than Overvoltage Cat. III
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Maintenance, Recalibration, and Repair
Cleaning and Storage
• The meter should be cleaned with a damp cloth and mild
detergent when necessary. Do not use solvents or abra-
sives.
• Store the meter in an area with moderate temperature
and humidity.
Battery Replacement
1. Remove the one rear Phillips head screw.
2. Open the battery compartment.
3. Replace the old battery with one 9 V battery.
4. Replace the cover and secure the screw.
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It is recommended that Digi-Sense products are
calibrated annually to ensure proper function and accurate
measurements; however, your quality system or regulatory
body may require more frequent calibrations.
To schedule your recalibration, please contact InnoCal, an
ISO 17025 calibration laboratory accredited by A2LA.
Phone: 1-866-INNOCAL (1-866-466-6225)
Fax: [phone]
E-mail: [email protected]
Web: InnoCalSolutions.com
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For Product and Ordering Information, Contact:
Toll-Free: 1-800-323-4340
Phone: [phone]
Fax: [phone]
ColeParmer.com/Digi-Sense
Toll-Free: 1-800-358-5525
Phone: [phone]
Fax: [phone]
Davis.com/Digi-Sense
Manual Part No. 00101-92
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[e-mail]
www.novatech-usa.com
Tel: [phone] Fax: [phone]
Tel: [phone] Fax: [phone]