Matrix MDM8145A User Manual

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USER MANUAL

Digital Multimeter

Model MDM8145A, MDM8146A, MDM8155A

USER MANUAL

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Summary of Contents for Matrix MDM8145A

Page 2: Table Of Contents
Contents 1. Safety Notices ....................... 2 2. Introduction ........................5 3. General indicators ......................7 4 Quick reference ......................7 4.1 Check the accessories of the product ..............7 4.2 The front panel at a glance .................. 8 4.3 Introduction to keys ....................9 4.4 Introduction to the display ..................
Page 3: Safety Notices
1. Safety Notices To avoid personal injury and prevent damage to the product, be sure to use this product in accordance with the manual. Before fully understanding and meeting the following warning, do not proceed to the next step.  Safety ground. The safety ground must be firmly connected to the ground pin at the power outlet and insert the instrument plug into a grounded outlet.
Page 4 Table 1 Different functions of input terminals Measurement function Input terminals Overload protection DC voltage 1000V DC or 750V AC AC voltage 1000V DC or 750V AC Frequency 250V DC and AC peak 2W resistance 1000V DC or 750V AC INPUT Capacitance 250V DC and AC peak...
Page 5 on, be sure to select the proper current input terminals based on the estimation. 4) The current input to the terminal 10 A must not exceed 11 A; otherwise, the internal fuse inside the multimeter will blow; and the current input to 200 mA terminal must not exceed 500 mA;...
Page 6: Introduction
2. Introduction MDM8145A / MDM8146A / MDM8155A is a full-featured, 19999 counting 4½ digit (MDM8145A / MDM8146A) / 199999 counting 5½ digits (MDM8155A) desk-type true-RMS digital multimeter with stable performance. The STM32 chip and external integration AD chip used by the meter offer strong overall functionality, excellent performance, and good experience for users;...
Page 7 Square wave output function (MDM8145A and MDM8146A optional)  Manual / automatic range setting function  Communication interfaces: USB Device, RS232 (MDM8145A and MDM8146A optional).  Support SCPI protocol and provide programming file  AC and DC voltage, DC current, two-wire / four-wire resistance measurement.
Page 8: General Indicators
3. General indicators 1-1 Mode of display: 3.5-inch LCD display; 1-2 Maximum display: 220 000 (5 1/2) automatic polarity display and unit digit display; 1-3 Range selection: automatic / manual; 1-4 Note to over-range: the screen displays "-OL-"; 1-5 Measuring rate: fast (6 times / sec), medium (4 times / sec), slow (1 times / sec);...
Page 9: The Front Panel At A Glance
 two backup power fuses  MDM81 user’s manual Optional accessories:  RS232 serial line  USB cable Standard and optional function / information of communication interface Function/communication interface Four and a half digits Five and a half digits Standard USB Device Standard Optional...
Page 10: Introduction To Keys
4.3 Introduction to keys See Figure 1.2.1 for keys: Freq HOLD Ω AC V SHIFT DC V AD+DC AUTO Period DUTY 2W 4W Enter TRIG EXIT DC I AC I -|(- SAVE Cont Figure 1.2.1 Keys Switch of multimeter Press the key to turn on or off the meter.
Page 11 Function: 1. Press the key to switch from automatic range to manual range and switch the range; 2. Adjust the frequency of the square wave output; 3. Browse the stored data; 4. Adjust the upper and lower limits; 、 Function: 1.
Page 12 AUTO 1. When the range is in manual mode, press the key to switch to the automatic range; 2. When the trigger mode is not automatic, press this key to switch to the automatic trigger; AC+DC Square wave output key, press the key to output a square wave signal with fixed amplitude and tunable frequency.
Page 13 External trigger function, press the key combination to enter the external trigger measurement mode; when a low pulse flows through the external trigger terminal, the system measures one time; press the key combination again to exit the external trigger function. (MDM8155A standard function, MDM8145A / MDM8146A optional function) SHIFT...
Page 14 SHIFT SAVE Upper limit comparison function, which is only effective in case of AC and DC voltage. When it is switched to the AC and DC voltage measurement function, press the key combination to enter the upper limit comparison function and the default comparison value is 1V;...
Page 15: Introduction To The Display
Maximum measurement key; press the key, and the system will determine according to the measured values, and the maximum value is displayed on the secondary display Minimum measurement key; press the key, and the system will determine according to the measured values, and the minimum value is displayed on the secondary display 4.4 Introduction to the display AUTO TRI...
Page 16: Introduction To The Back Panel
such as automatic (AUTO), 200mV, 2V, 20V, 200V, 1000V. When in automatic (AUTO) mode, the information represented by the number 3 appears. The second pane shows the measurement speed: There are three kinds of measurement speeds to choose from—slow (SLOW), Medium (MIDDLE), fast (FAST). The third and fourth panes are mainly used to display the operation function, when running the functions such as save (SAVE), (read) MEM, compare (COMP), external trigger (EXT), and DC + AC, the corresponding function information is shown on the third...
Page 17: Adjustment Of Handle
0.5A/250V fuse voltage selector: 110V/50Hz VAC or 220V/50Hz VAC RS232 interface（MDM8145A/MDM8146A optional） USB Device interface square wave output terminal（MDM8145A/MDM8146A optional） external trigger measurement port（MDM8145A/MDM8146A optional） current input fuse: 0.5A/250V fuse 4.6 Adjustment of handle To adjust the carrying handle of the digital multimeter, hold the handle by the sides and pull it outward.
Page 18: Turn On The Multimeter
4. When measuring the high voltage and high current, pay special attention to safety. 5. Because MDM8145A / MDM8146A / MDM8155A share the same measurement method, the measurement will be explained by taking the operation of MDM8155A as an example.
Page 19: Voltage Measurement
5.1 Voltage measurement Notes: Make sure that before the measurements, the terminals are connected correctly. To avoid damages to the multimeter, do not exceed the rating. 5.1.1 DC voltage measurement Range: 200mV, 2V, 20V, 200V, 1000V Input protection: the peak of 1000V for all ranges Measurement method: DC V 1.
Page 20 Figure 2.1.2 DCV terminal connection 5.1.2 AC voltage measurement Note: To ensure accuracy, the input value should be greater than 10% of the range. Range: 200mV, 2V, 20V, 200V, 750V AC technology: True RMS measurement Input protection: RMS of 750V for all ranges. Measurement method: AC V 1.
Page 21: Current Measurement
Figure 2.1.4 ACV terminal connection 5.2 Current measurement 5.2.1 DC current measurement Current measurement is designed for low and high current respectively with different methods of connection. Range for low current: 200uA, 2mA, 20mA, 200mA Range for high current: 2A, 10A. Measurement method: DC I 1.
Page 22 for current of 200mA and below, and connect the red and black test leads respectively to the proper input terminals. See Fig. 2.2.3 for current from 200mA to 10A, and connect the red and black test leads respectively to the proper input terminals. 3.
Page 23 AUTO TRI 1.99999 999.996Hz AUTO 2A AUTO Slow Local Figure 2.2.4 AC Current Measurement Notes: the measured current value is shown on the main display, and the value on the secondary screen represents the measured frequency of the current input signal 2.
Page 24: Resistance Measurement
Figure 2.2.6 Method of connecting test terminals for high current 5.3 Resistance measurement Note: Before measuring the resistance, disconnect the circuit power and discharge all high-voltage capacitors to avoid damages to the multimeter or the multimeter tested. Range: 200Ω, 2kΩ, 20kΩ, 200kΩ, 2MΩ, 20MΩ Measurement method: 5.3.1 2-wire resistance measurement Ω...
Page 25 Figure 2.3.2 2W resistance measurement terminal connection 5.3.2 4-wire resistance measurement Ω 2W 4W 1. When in the mode of 2-wire resistance measurement, press again to select four-wire resistance measurement. The four-wire resistance measurement interface is shown in Figure 2.3.3: AUTO TRI 4W Ω...
Page 26: Capacitance Measurement
Figure 2.3.4 4W resistance measurement terminal connection 5.4 Capacitance measurement Range: 20nF, 200nF, 2uF, 20uF, 200uF, 2mF, 10mF Measurement method: -|(- 1. Press to select the frequency measurement function. The capacitance measurement interface is shown in Figure 2.4.1: AUTO TRI 0.991 44.51% AUTO...
Page 27: Frequency Measurement
Figure 2.4.2 Capacitance measurement terminal connection 5.5 Frequency measurement Range: 20Hz, 200Hz, 2kHz, 20kHz, 200kHz, 2MHz, 20MHz Input sensitivity: 1.5V RMS Measurement method: Freq Period to select the frequency measurement function or cycle 1. Press measurement. The frequency / cycle measurement interface is shown in Figure 2.5.1: AUTO TRI Freq AUTO TRI...
Page 28: Diode And On-Off Test
Figure 2.5.2 Frequency/cycle measurement terminal connection 5.6 Diode and on-off test The measurement value is the forward voltage drop approximation, when the measured resistance is smaller than (30) Ω, the buzzer rings out, and displays the approximation; the voltage of the open circuit is about 2.8V Test condition: the forward DC current is approximately 1mA, and the reverse DC voltage no higher than 3V.
Page 29 3. According to Figure 2.6.2, connect the test leads to the terminals of the diode and read the display. Figure 2.6.2 Diode measurement terminal connection 5.6.2 On-off Test Cont 1. When in the diode test mode, press to select the on-off measurement. When the measured resistance value is greater than the threshold of the buzzer, it displays OPEN, and when the measured resistance value is smaller than the threshold of the buzzer, the resistance will be displayed.
Page 30: Duty Cycle Measurement
Figure 2.6.4 On-off measurement terminal connection 5.7 Duty cycle measurement DUTY HOLD 1. Press to enter the duty cycle measurement, and the duty cycle measurement interface is shown in Figure 2.7.1. AUTO TRI DUTY 50.000 AUTO Local Figure 2.7.1 Duty cycle measurement interface 2.
Page 31: Square Wave Output
5.8 Square wave output AC+DC Press to turn on the square wave output function and the mark of square wave (SWave) will appear in the measurement configuration bar. When it is turned on, the square wave is output directly. In this case, the screen displays the square wave output frequency, and the default frequency is 1kHz, as shown in Figure 2.8.1.
Page 32 OUTPUT 0,001,000 Clear AUTO Square Local Figure 2.8.3 Interface to select the adjustment position Press to adjust the square wave output frequency, as shown in figure 2.8.4; OUTPUT 0,001,090 Clear AUTO Square Local Figure 2.8.4 Interface to adjust the specific frequency The square wave output frequency is set up, and the square wave is output from the terminal on the back panel.
Page 33: Technical Indicators
AUTO TRI 1.99999 AUTO 2V AUTO Slow Local Figure 2.8.5 Switch from the interface of square wave output to that after the measurement of DC voltage AUTO TRI 1.99999 AUTO 2V AUTO Slow Local Figure 2.8.6 The interface of the latest measurement function after exiting from the square wave output 6 Technical indicators Limits of error: ±...
Page 34 100uV ±(0.2%+100) ±(0.8%+300) ±(2.5%+500) ±(5%+500) 200V ±(0.2%+200) ±(0.8%+450) 750V 10mV 40Hz~1kHz 1~2kHz ±(0.3%+200) ±(0.4%+200) Range Resoluti Limits of error (MDM8145A/Range of frequency 50Hz~1kHz） on ratio 200mV 10uV ±（0.8%+80） 100uV ±（0.8%+80） 1000uV ±（0.8%+80） ±（0.8%+80） 200V 10mV 750V 100mV ±（1%+50） Range Resoluti...
Page 35 10mV ±(0.5% +40) ±(1% +40) 750V 100mV ±(0.5% +40) 3. DC current measurement Range Range of Resoluti Limits of error measurement on ratio MDM8145A MDM8146A MDM8155A 200uA 0.001uA~220.000 0.001uA ±（0.35%+10） ±(0.15% +15) ±（0.05%+10） 0.01uA~2.20000m 0.01uA ±（0.35%+10） ±(0.15% +10) ±（0.05%+10） 20mA 0.1uA~22.0000mA...
Page 36 ± （0.4%+10） ±(0.2% +10) ±（0.04%+8） 20MΩ 100Ω~22.0000MΩ 100Ω ±（0.4%+15） ±(0.35% +10) ±（0.25%+6） 6. Capacitance measurement Range Range of Resoluti Limits of error measurement on ratio MDM8145A MDM8146A MDM8155A 0.001nF~2.200 0.001nF ±（3.5%+30） ±（2%+5） ±（2%+5） 20nF 0.01nF~22.00n 0.01nF ±（3.5%+30） ±（2%+5） ±（2%+5） 200nF 0.1nf~220.0Nf...
Page 37: Calibration
around 0.75mA 9. On-off measurement Range Range of Input protection Limits of error measurement 200Ω level 0~30Ω 250Vp Input current is around 0.75mA, when the resistance is smaller than 30Ω, the buzzer rings out 10. Square wave output Output Output frequency Output amplitude Square wave 1Hz~100kHz...
Page 38 Definition The position represents the current calibration function The position represents the current range of calibration The position represents the current value entered The position is used to input the RMS The position represents the current measurement value 4. The calibration data can only be written into FLASH when all levels are calibrated and the secondary display shows OK, so that the calibration data can be permanently retained.
Page 39 200V: short circuit for the input terminals, after the measured value is stable press Enter to confirm. Then according to the prompt, enter 200V, then set the true value, after the measured value is stable press Enter to confirm. Then the calibration for 200V range is completed, and the program will automatically switch to the 1000V level, and change the prompt.
Page 40 measured value is stable press Enter to confirm. Then the calibration for 750V range is completed, and the secondary display shows OK. Then the calibration of ACV is complete, and the program will write the above calibration data into FLASH. 3.
Page 41 prompt. 10A: open circuit for the input terminals, after the measured value is stable press Enter to confirm. Then according to the prompt, enter 2A, then set the true value, after the measured value is stable press Enter to confirm, and the secondary display shows OK.
Page 42 measured value is stable press Enter to confirm. Then the calibration for 2A range is completed, and the program will automatically switch to the 10A level, and change the prompt. 10A: Input 200mA, after the measured value is stable press Enter to confirm. Then according to the prompt, enter 2A, then set the true value, after the measured value is stable press Enter to confirm, and the secondary display shows OK.
Page 43 200kΩrange is completed, and the program will automatically switch to the 2MΩ level, and change the prompt. 2MΩ: short circuit for the input terminals, after the measured value is stable press Enter to confirm. Then according to the prompt, enter 2MΩ, then set the true value, after the measured value is stable press Enter to confirm.
Page 44: Communication Interface
FLASH. 8 Communication interface MDM8155A is equipped with communication interfaces: RS232 and USB. MDM8145A / MDM8146A are equipped with communication interface USB, the RS232 communication interface is optional. 1. Connection and setting of RS232 interface: The meter is connected to the computer via a parallel one-male-and-one-female serial port line.
Page 45: Installation And Use Of Relevant Software
8-digit data, 1 stop bit, no parity check. 2. USB Device interface The meter is connected to the computer through a USB port and then a square line The USB drive for STM32 USB should be installed on the computer to use the USB.
Page 46 2) Find the location of the fuse; remove the blown fuse according to the prompts on the instrument. 3) Replace the fuse, and install the new fuse.

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Mdm8146a Mdm8155a