Extech Instruments MG325 User Manual Download Page 13

13                                    MG325-en-GB_v1.1   3/16 

 

6.9.1 Disable Lock Mode for Insulation and Continuity Tests 

To disable test lock mode and use manual test mode, press and hold the 

 button until the 

lock icon switches off and then press and hold the 

TEST

 button for the duration of the test (

TEST

 

will be displayed). Release the button to stop the test. 

6.9.2 Insulation Resistance Test Timer 

Please read and understand the sections on Insulation Resistance testing and Safety before 
continuing.  

The MG325 can run an Insulation test for an indefinite period by pressing the TEST button to 
start/stop tests (Timer function OFF) or it can be programmed to run a test for a specific period of 
time, 1~10 minutes (Timer function ON). 

1.  Short press the 

 button to turn the test timer ON or OFF (the 

TIMER

 icon will display 

when the timer is active). 

2.  The test time, while the Insulation Resistance test is running, is shown in the auxiliary display 

in ‘seconds’ (s). 

3.  To set the test time, press and hold the SETUP button to enter the SETUP mode. Press 

 to step to the 2

nd

 menu item (test time) and use the arrow buttons to select a test time 

between 1~10 minutes. Press 

 to confirm the setting and then press and hold the 

SETUP button to exit the SETUP mode. See SETUP mode section for additional details. 

4.  Now when Insulation tests are run, and the 

 

button is pressed, the tests will stop 

automatically after the programmed test time has elapsed.  

5. Press 

 to turn this function off (TIMER display prompt will switch OFF). 

6.9.3 Dielectric Absorption Ratio [DAR] Insulation Testing 

Read and understand all operations and safety information in the Insulation Resistance 
measurement and Safety sections before continuing. 
1.  Connect the meter to the device under test as shown in the Insulation Resistance test section 

above. 

2.  Select the desired output test voltage using the rotary function switch. 

3. Use 

the 

PI/DAR

 button to step to the first DAR test mode (60 seconds : 15 seconds ratio test) 

or to the second DAR test mode (60 seconds : 30 seconds ratio test). 

4.  The display will show the DAR icon when the DAR mode is successfully accessed. 

5.  The test time ratio will show on the lower right. 

6. Press 

the 

TEST

 button to start the test.  

7.  During the test the auxiliary display digits show the elapsed time, the voltage alert flashes on 

the upper left, and the ‘test voltage alert’ LED will light. 

8.  The test will stop automatically after 60 seconds. 

Summary of Contents for MG325

Page 1: ...USER MANUAL Insulation Tester DMM Model MG325 ...

Page 2: ... RESISTANCE MEASUREMENTS 9 6 7 CONTINUITY MEASUREMENTS 10 6 8 CAPACITANCE MEASUREMENTS 11 6 9 INSULATION RESISTANCE MEASUREMENTS 12 6 9 1 Disable Lock Mode for Insulation and Continuity Tests 13 6 9 2 Insulation Resistance Test Timer 13 6 9 3 Dielectric Absorption Ratio DAR Insulation Testing 13 6 9 4 Polarization Index PI Insulation Testing 14 6 9 5 Comparator Utility 14 7 DATA RECORDING 15 8 SET...

Page 3: ...Voltage Leakage Current Insulation test mode Capacitance Measurements Low Resistance and Continuity Measurements with ZERO function Auto Ranging measurments Polarization Index PI and Dielectric Aborption Ratio DAR tests Five 5 Insulation Resistance test voltages 50 100 250 500 and 1000V Insulation Resistance tests in 10 voltage steps from 50 to 120 of range Eight 8 Insulation Resistance measuremen...

Page 4: ... has been designed for safe use but must be operated with caution The rules listed below must be carefully followed for safe operation 1 NEVER apply voltage to the meter that exceeds the specified maximum Input Protection Limits Function Maximum Input V DC or V AC 600VDC AC rms Low Resistance 250VDC AC rms Capacitance 250VDC AC rms Insulation Resistance and Continuity 250VDC AC rms Surge Protectio...

Page 5: ...s to avoid electrical shocks when measuring Do not apply signals greater than those specified between any two terminals or any terminal and ground Set the function switch the correct position before beginning a test Never move the function switch during a test Please stop testing and remove connections to the circuit under test before moving the function switch to a new position Do not store or us...

Page 6: ...menu navigation and for scrolling recalled readings 8 Down arrow for menu navigation and scrolling recalled readings Also used to select capacitance or resistance modes when the function switch is set to the capacitance and resistance position 9 Press to start Insulation or Low Resistance tests Insulation tests output high voltages and measure insulation resistance 5 Symbols and Annunciators 1 Tes...

Page 7: ...replaced See the Maintenance section for details on battery and fuse replacement 6 4 DC VOLTAGE MEASUREMENTS CAUTION When the measured voltage is 42VDC or 600VAC the meter flashes the warning icon on the upper left Do not measure DC voltages if a motor on the circuit is being switched ON or OFF Large voltage surges may occur that can damage the meter 1 Set the function switch to the position 2 Ins...

Page 8: ...ng icon on the upper left Do not measure AC voltages if a motor on the circuit is being switched ON or OFF Large voltage surges may occur that can damage the meter 1 Set the function switch to the position 2 Insert the black test lead banana plug into the negative EARTH jack 6 Insert red test lead banana plug into the positive V jack 7 3 Touch the black test probe tip to the neutral side of the ci...

Page 9: ... the test probes and note the value Short the test probes again and press and hold ZERO until ZERO is displayed 0 00Ω reading when successful Press and hold ZERO again to exit 5 Before testing it is best to disconnect one side of the part under test so that other circuits do not interfere with the resistance reading 6 Touch the test probe tips across the circuit or part under test 7 Read the resis...

Page 10: ... must be held throughout the test 5 Reset the display to zero before testing Short the test probes and note the value Short the test probes again and press and hold ZERO until ZERO is displayed 0 00Ω reading when successful Press and hold ZERO again to exit 6 Touch the test probe tips across the circuit or part under test 7 If the continuity buzzer is turned on in the SETUP mode the buzzer will so...

Page 11: ...e the button to choose the Capacitance mode the button toggles Capacitance and Resistance modes 4 Touch the test probe tips across the circuit or part under test 5 Read the capacitance in the main display and with the lower bargraph 6 Short press the H Hold button to freeze H icon displayed or unfreeze no H icon displayed the displayed reading 7 Press to store the reading Note that the Auto Power ...

Page 12: ...nt display 6 The meter defaults to test lock mode lock icon displayed so the test will run without having to hold the TEST button 7 Press the TEST button to stop the test 8 At the end of each test the high voltage switches off alert symbol and LED light switch off the measured resistance value is held in the primary display and the meter internally discharges the balance of the test voltage 9 Shor...

Page 13: ...t time between 1 10 minutes Press to confirm the setting and then press and hold the SETUP button to exit the SETUP mode See SETUP mode section for additional details 4 Now when Insulation tests are run and the button is pressed the tests will stop automatically after the programmed test time has elapsed 5 Press to turn this function off TIMER display prompt will switch OFF 6 9 3 Dielectric Absorp...

Page 14: ...uing In Comparator mode the meter compares Insulation Resistance or Continuity measurements to a preset resistance value and displays PASS measured value greater than reference value or FAIL measured value lower than reference value 1 Connect the meter to the device under test as shown in the Insulation Resistance or Continuity test sections above 2 Press the COMP button momentarily and the COMP i...

Page 15: ...st voltage from 50 to 120 of the range 3 Press to confirm and to step to the default test time 4 Use the arrow buttons to set the default test time from 1 to 10 minutes 5 Press to confirm and to step to the comparator reference value setting 6 Use the arrow buttons to select the comparator reference value from 500kΩ to 500MΩ 7 Press to confirm the setting 8 Press and hold the SET button until the ...

Page 16: ...battery cover 1 Turn power off and disconnect the test leads from the meter 2 Open the rear battery cover by removing three screws using a Phillips screwdriver 3 Insert the six 6 1 5V AA batteries into battery holder observing the correct polarity 4 Put the battery cover back in place Secure with the screws You as the end user are legally bound EU Battery ordinance to return all used batteries dis...

Page 17: ...approximately Resistance 0 001k 10M 0 001k 0 1M 3 0 reading 3 digits Capacitance 0 1nF 500µF 0 1nF 0 1µF 5 0 reading 5 digits Insulation Resistance Measurements Test Voltage Range Min Resolution Accuracy 50V 0 00M 0 99G 1 00G 10 0G 0 01M 0 01G 0 01G 0 1G 3 3 digits 3 3 digits reading 4 G 100V 0 00M 0 99G 1 00G 20 0G 0 01M 0 01G 0 01G 0 1G 3 3 digits 3 3 digits reading 2 G 250V 0 00M 0 99G 1 00G 50...

Page 18: ...range indication is displayed in Insulation Resistance and Continuity modes Auto Power Off After 10 minutes of inactivity Polarity Automatic no indication for positive Minus sign for negative Measurement Rate 2 times per second nominal Low Battery Indication is displayed if battery drops below operating voltage Battery Six 6 1 5V AA batteries Consumption 500mA at a 1000V test voltage 17mA in nomin...

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