Zhengzhou Ming He Electronic Technology VAM7520P User manual

OPERATING MANUAL
December 2013
Zhengzhou Ming He Electronic Technology Co., Ltd.
VAM7520P
Voltage Meter

Contents
1. Contact.....................................................................................................................1
2. Inspecting Package Contents...............................................................................1
3. Summary..................................................................................................................1
3.1 Brief introduction............................................................................................1
3.2 Main function..................................................................................................2
3.3 Technical data ................................................................................................2
4.Instrument Introduction...........................................................................................3
4.1 Structure Description.....................................................................................3
4.2 Wiring...............................................................................................................3
5. Operation..................................................................................................................4
5.1 Wiring...............................................................................................................5
5.2 Output..............................................................................................................5
5.3 Debug mode...................................................................................................5
5.4 The functions of debug mode......................................................................6
6. Cautions...................................................................................................................8
7. Warranty and service ............................................................................................8

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1. Contact
Address: No.96 Rui Da Rd., Zhengzhou, China
Tel: [phone]
Fax: [phone]
Zip: 450001
E-mail: [email protected]
Website: www.mhinstek.com
2. Inspecting Package Contents
When you get a new VAM7520P Voltage Meter, please inspect the instrument
as follows:
2.1 Check if there is damage due to transportation
If the package is damaged, please retain them until the instrument and
accessories are tested.
2.2 Check package contents
Contents of the case are as bellows, if the content does not match with the
packing list or the instrument is damaged, please contact us.
VAM7520P Voltage Meter 1pc
User manual(pdf) 1pc
2.3 Check the machine
If the machine was damaged; did not work properly or failed to pass
performance tests, please contact your dealer or our company.
3. Summary
3.1 Brief introduction
VAM7520P is a new-type voltage meter which can measure

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voltage,current,power,charging capacity and time at the same time. It also can
set the over voltage protection,over current protection,over power protection,
over charging capacity protection,over time protection and low-voltage
protection.The voltage meter adopts two groups of LED digital tubes to display
the data. The meter can switch the display among different physical
quantities.This meter is ideal for monitoring the output voltage and current, as
well as the battery charge and discharge applications.
3.2 Main function
1、Dual display for voltage and current, and available for switching display
power, charge capacity and time.
2、Flexible calibration function, you can calibrate the voltage and current value
by yourself.
3、4-bit LED digital tube, in which 3-bit for measuring and one-bit for the unit.
4、With an output shutdown function key, you can turn on or off the output
flexibly.
5、With over voltage, low-voltage, over current, over power,over charging and
over time protection functions.
3.3 Technical data
Item
Parameter
Input voltage
Two wire system
10V~75V
Three wire system
0~75V
Output current
0~20A
Display
4 bit LED（3 bit for value and 1 bit for unit）
Display
resolution
Voltage
0.01V
Current
0.01A
Power
0.01W
Capacity
0.01AH
Time
0.01H
Accuracy
Voltage
±1％+2 bytes
Current
±2％+5 bytes
Measuring rate
5times/s

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Protection
types
OVP(Over-voltage
protection)
0.01V~75V
OPP(Over power
protection)
0.01W~9.99kW(“P”represents W ，“P.”
represents kW)
OCP(Over-current
protection)
0.01~20A
OAH(Over charge
protection)
0.01AH~999AH
OFT(Overtime
protection)
0.01 hour~99.9 hour
LoP(Low-voltage
protection)
Dimensions(W*H*D)
79×43×52（mm）
Installing hole (mm)
76.5*39.2（mm）
3-1 Technical data
4.Instrument Introduction
4.1 Structure Description
Item
Introduction
1
Button
2
LED digital tube
3
Operation Tips
4-1 The introduction of VAM7520P
4.2 Wiring
On the back of the meter there are three terminals on the right, they are “IN－”,
“＋”and “OUT－”, the”＋”is the public terminal of “IN +”and “OUT +”, the

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“Vext”on the left side of the meter, it is used for three-wire system.
This meter has two-wire and three-wire dual input methods. Two wire system
can connect the meter to the circuit directly, three-wire system requires an
external power supply for the instrument.
4.2.1 Two-wire wiring diagram and methods
4-2 Wiring diagram of two-wire
There are three terminals on the right side, top down, they are “IN－”, “＋”and
“OUT－”, the”＋”is the public terminal of “IN +”and “OUT +”. Be careful not to
reverse, the jumper cap in the lower left corner should be picked up on the 2W.
4.2.2 Three-wire wiring diagram and methods
4-3 Wiring diagram of three-wire
There are three terminals on the right side, top down, they are “IN－”, “＋”and
“OUT－”, the”＋”is the public terminal of “IN +”and “OUT +”. Be careful not to
reverse, the jumper cap in the lower left corner should be picked up on the 3W.
Two terminals "Vext (+, -)" at the left end require an external power supply of
the meter, the voltage of the external power supply is DC12V ~ 60 V, three-wire
system can measure voltage under 10V.
5. Operation

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5.1 Wiring
Select the appropriate wiring according to the range of the measured voltage,
ensuring input voltage is within the tolerance range of the instrument.
Note: The input voltage range of two-wire : 10V ~ 75V;
The input voltage range of three-wire : 0V ~ 75V.
5.2 Output
Power on, the above digital tube will display voltage value in default, the below
digital tube will display “- OFF” in default, it means that the output is turned off ,
press the “OUT”button to output .
Press the button to select the above display of the digital tube, press
the button to select the below display of the digital tube. Flexibility to switch
the display of voltage (V), current (A), power (P), capacity (C) and time (H).
If you want to open the output function when boot, you need to enter debug
mode.
In addition, the following settings are also need to enter debug mode,
respectively:
1, You need to enable the overvoltage protection (OVP), under voltage
protection (LoP), over current protection (OCP), over power protection (OPP),
over-charging capacity protection (OAH) and overtime protection (OFT)
2, When there is a certain error of the measured voltage or current value and
need to be calibrated.
3, When the parameters are confused, need to restore factory settings.
5.3 Debug mode
Enter debug mode : In the normal state, press the < OUT >key for a while,
you have entered the debug mode when the the upper row of digital tube
displays "0-U ", press < OUT > key again , the upper row of digital tubes
display alternately among “0 - U”, “1 -C”, “2 - ES”, “3 - r”, “4 -ON”, “5 - OV”, “6 -
OP”, “7 - OC”, “8 - AH”, “9 - Hr”and “10 - L” ,each one represents a function.

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Exit debug mode : In the debug mode, you can exit by pressing the < OUT >
button for a while.
5.4 The functions of debug mode
5.4.1 "0 - U" is the calibration of the voltage value, the voltage value displays in
the digital tube is the current measure value. We can choose two points to
calibrate the voltage. Generally, we choose 32V as the high voltage point, 12V
as the low voltage point. The demarcation criterion of highs and lows is 20V.
Above 20V is the high point voltage in default, less than 20V is the low point
voltage in default. Now we can compare to a standard voltmeter, press key
to increase the voltage measure, press key to decrease the voltage
measure, two points will affect each other. After adjusting back and forth 2-3
times,the measured values can be consistent with the values of the standard
voltmeter.
5.4.2 "1 - C" is the calibration of the current value, the current value displays in
the digital tube is the current measure value. We can choose two points to
calibrate the voltage. Generally, we choose 3A as the high current point, 0.1A
as the low current point. The demarcation criterion of highs and lows is 2A,
Above 2A is the high point current in default, less than 2A is the low point
current in default. Now we can compare to a standard ammeter, press key
to increase the current measure, press key to decrease the current
measure, two points will affect each other. After adjusting back and forth 2-3
times,the measured values can be consistent with the values of the standard
ammeter.
5.4.3 "2 - ES" is the function to save parameters. When you need to save
parameters, adjusting to the "2 - ES", the digital tube displays "-n-" by default,
indicating that don’t save the parameters, you can adjust to "- y -" by pressing
or , then press < OUT >,the meter will save parameters and exit the
debug mode automatically.

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5.4.4 "3 - r" is to restore factory settings, if you want to return to the initial value,
you can adjust to "- y -" by pressing or , then press< OUT >, it will
restore to the factory setting.
5.4.5 "4 - ON" is to set whether the output is open or not when boot, the default
display is "- n -," indicating not open, if you want to output when boot, you can
adjust to "- y -" by pressing or , then save the parameters.
5.4.6 "5 - OV" over voltage protection (OVP), if you have set the OVP value,
when the input voltage exceed the setting value, the machine will automatically
cut off the output, at the same time the screen displays protection type is "
OVP," press any key to return to normal.
5.4.7 "6 - OP" over power protection (OPP), if you have set the OPP value,
when the actual output power exceed the setting power, the machine will
automatically cut off the output, at the same time the screen displays
protection type is "OPP", press any key to return to normal.
5.4.8 “7 - OC" over current protection (OCP) , if you have set the OCP value,
when the output current exceed the setting value, the machine will
automatically cut off the output, at the same time the screen displays
protection type is "OCP", press any key to return to normal.
5.4.9 “8 - AH" over charging capacity protection (OAH), if you have set the
OAH value, when the output AH exceed the setting value, the machine will
automatically cut off the output, at the same time the screen displays
protection type is "OAH". What should be noted is that the AH value is a
cumulative value, once exceed, it will not output again , at this time, you can
press for a while to clear electric quantity value and time value to ensure
that the electric quantity can be output again .
5.4.10 "9 - Hr"over time protection (OFT), if you have set the OFT value, when
the output time exceed the setting time , the machine will automatically cut off
the output,at the same time the screen displays protection type is "OFT". If you
need to output again , you can press for a while to clear the time .

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5.4.11 "10 - L" low-voltage protection (LoP), if you have set the LoP value,
when the output voltage is less than the setting voltage , the machine will
automatically cut off the output, at the same time, the screen display protection
type is "LoP", press any key to return to normal.
Attentions: "5 - OV" to "10 - L" represent the different protection setting values,
the default is 0, indicating don’t use the protection functions,the non-zero
parameter means using the protection function, after setting the parameters, it
need to be saved in "2 - ES" .
If you have set the protection function of the meter, and want to return to the
not enable state, you can press button for a while under the normal mode.
6. Cautions
6.1 Don’t exceed the range of the meter, otherwise it will damage the module.
6.2 Connect input and output properly , it is forbid to reverse connection,
otherwise it will not measure correctly.
6.3 Operating temperature is from -10 to 50 degrees Celsius, and storage
temperature is from -20 to 70 degrees Celsius; make sure the instrument kept
dry.
6.4 Do not attempt to disassemble the instrument, destroying the package will
void the warranty, this instrument has no user-serviceable parts inside, if it
need to be repaired, you can repair it by specifying outlets, or return to the
factory for repair.
6.5 Do not move the instrument violently as it is working to avoid irreparable
damage to the internal circuitry.
7. Warranty and service
Thank you for purchasing our products. To maximize the use of the new
product features, we recommend that you take the following steps:
1 Read safe and efficient use instruction.
2 Read the warranty terms and conditions.
We warrants to the original purchaser that its product and the component parts