User's Guide 99 Washington Street Melrose, MA 02176 Phone 781-665-1400 Toll Free 1-800-517-8431 Visit us at www.TestEquipmentDepot.
Introduction Congratulations on your purchase of this Extech MA640 True RMS Clamp Meter. This meter measures AC/DC Current, AC/DC Voltage, Resistance, Capacitance, Frequency, Diode Test, Duty Cycle and Continuity. Special features include Thermocouple Temperature and NonContact Voltage detection. The double molded case is designed for heavy duty use. This meter is shipped fully tested and calibrated and, with proper use, will provide years of reliable service.
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. Remove the battery if meter is to be stored for longer than 60 days. WARNINGS • • • • Set function switch to the appropriate position before measuring. When measuring volts do not switch to current/resistance modes. Do not measure current on a circuit whose voltage exceeds 600V.
Description Meter Description 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Operation NOTES: Read and understand all Warning and Caution statements in this operation manual prior to using this meter. Set the function select switch to the OFF position when the meter is not in use. Non-Contact Voltage Detector WARNING: Risk of Electrocution. Before use, always test the Voltage Detector on a known live circuit to verify proper operation. 1. Rotate the Function switch to any measurement position. 2. Place the detector probe tip on the conductor to be tested. 3.
AC/DC Voltage Measurements CAUTION: Do not measure voltages if a motor on the circuit is being switched ON or OFF. Large voltage surges may occur that can damage the meter. 1. Rotate the function switch to the V position. 2. Press the MODE button to select AC or DC Voltage. 3. Insert the black test lead banana plug into the negative COM jack. Insert the red test lead banana plug into the positive V jack. Touch the black test probe tip to the negative side of the circuit.
Diode Test 1. Connect as described for resistance measurements 2. Press the MODE button to select diode test 3. Touch the test probe tips to the diode or semiconductor junction under test. Note the meter reading. 4. Reverse the test lead polarity by reversing the red and black leads. Note this reading. 5. The diode or junction can be evaluated as follows: . If one reading displays a value (typically 0.400V to 01.800V) and the other reading displays OL, the diode is good.
Frequency and Duty Ratio Measurements 1. Rotate the function switch to the Hz Position. 2. Press the MODE button to select AC Voltage 3. Press the HZ % button to select HZ 4. Insert the black test lead banana plug into the negative COM jack. Insert the red test lead banana plug into the positive Hz jack. 5. Touch the black test probe tip to one side of the device. Touch the red test probe tip to the other side of the device. 6. Read the Frequency value on the display. 7.
Data Hold To freeze the LCD reading, press the HOLD button. While data hold is active, the HOLD icon appears on the LCD. Press the HOLD button again to return to normal operation. MAX/MIN 1. 2. 3. Press the MAX/MIN button to activate the MAX/MIN recording mode. The display icon "MAX" will appear. The meter will begins recording and displaying the maximum value measured. Press the MAX/MIN button and “MIN” will appear. The meter will display the minimum value measured during the recording session.
Maintenance WARNING: To avoid electrical shock, disconnect the meter from any circuit, remove the test leads from the input terminals, and turn OFF the meter before opening the case. Do not operate the meter with an open case. Cleaning and Storage Periodically wipe the case with a damp cloth and mild detergent; do not use abrasives or solvents. If the meter is not to be used for 60 days or more, remove the battery and store it separately. Battery Replacement 1.
Specifications 0.01A Accuracy (% of reading + digits) ±(2.8% + 8 digits) 600.0 AAC 0.1A ±(3.0% + 8 digits) 60.00 AAC 0.01A ±(2.8% + 5 digits) 600.0 ADC 0.1A ±(3.0% + 5 digits) 6.000 VAC 0.001V 60.00 VAC 0.01V 600.0 VAC 0.1V Function Range AC Current 60.00 AAC 50/60 Hz True RMS DC Current AC Voltage True RMS DC Voltage Resistance Capacitance Frequency Resolution ±(1.8% + 8 digits) 600.0 mVDC 0.1mV 6.000 VDC 0.001V 60.00 VDC 0.01V 600.0 VDC 0.1V 600.0Ω 0.1Ω 6.000kΩ 0.
General Specifications Clamp jaw opening Display Continuity check Diode test Low Battery indication Over-range indication Measurement rate Thermocouple sensor Input Impedance AC current bandwidth AC voltage bandwidth AC response Crest Factor Operating Temperature Storage Temperature Operating Humidity Storage Humidity Operating Altitude Battery Auto power OFF Dimensions & Weight Safety Approvals 1.5" (40mm) approx. 6000 count backlit LCD Threshold 60Ω; Test current < 0.35mA Test current of 0.
