DIGITAL MULTIMETERS VOAC7523H / 7522H / 7520H / 7521H

Display digits 5.5-digit 　
Isolated 2-channel input
Dual function and dual display 　
DCV max. resolution 0.1µV 　
4-terminal resistance measurement
(VOAC7522H / VOAC7521H only) 　
DC, AC, (DC+AC) 10A range

Features

Isolated 2-channel input (VOAC7523H / VOAC7520H only)

The VOAC7523H/VOAC7520H can measure two independent voltage systems. This allows measurement of two potential differences or input and output voltages in a circuit with a single unit. The figure on the right shows an example connection.

Dual function and dual display

Conventional measuring instruments require disconnecting input cables and switching functions in order to perform different measurements; the VOAC752xH series can perform measurements that used to require multiple units with a single unit, thereby improving the efficiency of measurement work. For example, if you want to measure power consumption (apparent power, VA), you can measure and calculate voltage and current with a single unit, allowing you to measure power in real time.
* The units (V, A, Hz) on the display are not shown on the actual device. The units of data on the left side of the display are indicated by the corresponding “FUNCTION” key lighting up. The units (V, A, Ω/AC, dBm) of the data on the right side are indicated by LED lights in the “SUB DISP UNITS” section in the upper right portion of the display. See the “Specifications” page for details.

Maximum display 509999

The number of displayed digits does not change for the VOAC752xH series.
1.00000V when measuring 1V
5.00000V when measuring 5V

Three types of interfaces are available

The standard interface is RS-232. You can select LAN (Ethernet 10BASE-T) or GP-IB optionally.

Long interval measurement up to 3000 hours

The interval measurement, which can be configured from 10ms to 3600s, and the data storage function with up to 3000 timestamps can be used to measure from 30s to 3000 hours.

True RMS value measurement

True RMS AC voltage and AC current can be measured. RMS values including DC can also be measured.

Versatile computing functions

You can perform decibel operations (dBm, dBµ), scaling operations (SCLE), moving averages (AVG), differential operations (REL), statistical operations (MAX, MIN, X, σ), comparison operations (COMP), and arithmetic operations between dual functions.

Front panel

① Easy-to-read fluorescent display tube

The single display shows the measured value and its attribute information (time stamp, function, and range), while the dual display shows the measured value for the left and right different functions. The photo above shows a dual display of two DCVs. The photo above shows a dual display of two DCVs. Single display can also be shown as shown on the right.

② Signal input section

VOAC7523H / VOAC7520H is a common input section for voltage, resistance, temperature, and frequency, 0.5A and 10A current inputs, and CH-B measurement input section. In the VOAC7522H / VOAC7521H, the CH-B measurement input section is the 4-terminal resistance measurement input section.

③ FUNCTION area

You can select measurement items. The button corresponding to the function currently being measured lights up.

④ RANGE area

The measurement range can be selected. In the case of AUTO range, measurement is made at the optimum range according to the input signal.

⑤ SAMPLE area

Allows selection of measurement sample rate, retention of measurements and single measurements.

⑥ SUB DISP UNITS area

The units on the sub side (right side) of the dual display are indicated by the lighting of LEDs.

⑦ DISP area

Switch between single-display and dual-display measurements, and switch between main and sub-functions.

⑧ UTILITY area

It is possible to select calculation items, save and read measurement data and panel settings, and configure system settings.

Setting items	Description of contents
REF	Reference value setting (any value)
AVG	Averaging count setting(2～255)
COMP	Comparator operation comparison value setting (upper and lower limit setting)
SCLE	Scaling operation (X- A) × B / C, D / X to set any number
MAX / MIN	Statistical calculation mode setting (calculates maximum, minimum, mean, and standard deviation within a specified number of samples). In addition, the continuous (CONT) operation performs a peak hold of the maximum and minimum values during the measurement period.
Ω <	Threshold operation for continuity test (continuity test can be performed simultaneously with resistance measurement)

Back Panel

Main unit options

■SC-351 (LAN interface) … Photo upper section

This product can be connected to a PC via Ethernet using the TCP/IP network interface. You can also connect the product directly to your PC one-on-one via a cross-network cable.
An external controller (usually a PC is used) can be used to perform button operations on the main unit equivalent to those performed by hand. This enables not only simple operation, but also collection of measurement result data and construction of automatic measurement systems.

Interface specifications：10Base-T
* GPIB interface SC-353 cannot be mounted simultaneously.

■SC-354 (D/A output) … Photo lower section

Any three digits of the measured value are converted to D/A and output as analog values.
The output voltage can be selected in three ways：±99.9mV/ ±999mV/±9.99V.
The device outputs upper or lower limit values when overloaded.

The figure below shows an example of D/A output with an output range of ±9.99 V.

Floating measured results can be output as D/A output and connected to a sequencer, etc. without the use of an external amplifier.
*1. DIO interface SC-352 cannot be mounted simultaneously.

■SC-353 (GPIB interface) … Photo upper section

This product allows you to control the main unit using the GPIB interface.
An external controller (usually a PC is used) can be used to perform button operations on the main unit equivalent to those performed by hand. This enables not only simple operation, but also collection of measurement result data and construction of automatic measurement systems.

Electrical, mechanical and functional specifications：Complies with IEEE Std. 488.1-1987 and JIS C 1901-1987
Specifications for command formats, protocols, etc.：Complies with IEEE Std.488.2-1987

* 1 LAN interface SC-351 cannot be mounted simultaneously.
* 2 Compatibility for the command system of IWATSU ELECTRIC digital multimeters VOAC7521H/7520H/7522H/7523H, VOAC7411/7412/7413, and VOAC7510/7511/7512/7513 Series is inherited. However, the optional GP-IB unit SC-303A cannot be mounted.

■SC-352 (DIO interface) … Photo lower section

When a comparator operation is performed with the DIO interface (optional) installed, the comparison operation result is output to the HI/GO/LO of the DIO output terminals using an open collector (DC40V, 100mA drive is possible).

The figure below is an example of a connection that uses this output to make a pass/fail judgment.
Indicates when the comparison operation result is GO.

DIO comparator operation timing
Set Yellow-HI/LO/Red-HI/LO in the comparator menu.

After the trigger is entered, the STRB signal indicating the end of measurement becomes “L,” and the threshold selected in the DIO output (YELLOW or RED selection) updates either HI/GO/LO of the output and shorts to GND.

* D/A output SC-354 cannot be mounted simultaneously.

■SC-525 (RS232-USB converter) (option)

By adopting a cross cable and using the RS connector as a female connector, it is possible to directly connect the USB port and the measurement equipment.
You can use an external controller (usually using a PC) to perform the same operations as when you manually control using button operation on the main unit. Not only operations, but also measurement result data collection is possible (interface specifications are the same as the standard RS-232).
It can also be used for VOAC752X Series, signal generator SG-41XX Series, universal counter SC-720XH Series, digital oscilloscope BRINGO® Series, etc.
Supported OSs：WindowsXP, Vista, 7, 10

High voltage, high current and high resistance measurement

SC-004 (Measurement lead for high resistance)

Because it uses a shielded cable, it has a structure that is less susceptible to external noise when measuring high resistance.
(Use range 2MΩ to 100MΩ)

Resistance measurement

TKL 90cm BAN [4-wire Kelvin test lead (4-terminal resistor measuring cable)]

By reducing the influence of conductor resistance and contact resistance on the measurement cable, it is possible to measure resistance with high precision. In particular, this is beneficial in the measurement of low resistance (manufactured by PMK).

Temperature measurement

SC-0107H (Sheath type thermocouple type K)

This thermocouple is a sheath-shaped temperature sensor that integrates a metal protective tube (sheath) and a detection element.
Between the sheath and the detection element (thermocouple element wire), it is filled tightly with inorganic insulators such as magnesium oxide, maintaining the insulation while leaving the inside airtight to prevent corrosion by gas under air and high temperature. It has excellent earthquake resistance and can be used under adverse conditions such as high temperature, high pressure, and corrosive atmosphere. It can be bent freely, and it can be mounted in places where there is a lot of bending. It has very good features for use, such as a narrow outer diameter, which allows it to be used for temperature detection even in narrow places and for small measured objects. Also useful for measuring liquids and gases
(-40℃～+650℃)

SC-0116 (Thermocouple type K for stationary surfaces)

The most common detector for stationary surface temperature, it detects the surface temperature at a fast response rate of 2 to 3 seconds. The thermocouple wire is also less deformed and can be used in a wide range of applications, from laboratories and experiment facilities to field measurements.
For example, it is suitable for measuring the heating temperature of motors, measuring the rising temperature of transformers, and measuring the temperature of molds.

As long as the sensor part can be contacted vertically, the temperature of various objects can be measured.
(0℃～+500℃)

POMONA 1286 (banana plug)

The measurement terminal of the VOAC752xH Series is a banana plug, but the banana plug terminal does not protrude outside the panel surface of the equipment. This means that bare wires cannot be connected directly, so by using this option, it is possible to directly connect bare wires such as commercial thermocouples.

Test lead for VOAC 752xH (can also be used with VOAC 752x Series)

SC-020 (Test lead)

* Standard accessory

SC-026 (Arrow clip)

You can pinch the measured object by attaching it to the tip of the SC-020. This is convenient for pinching IC lead wires.
(AC30V / DC60V / DC3A)

[To be discontinued after stock is sold out]

SC-023 (Crocodile clip H)

crocodile clip for high voltage measurement. It is used by attaching it to the tip of SC-020.
(600Vrms, CAT II/10A)
* CAT II：Primary circuit of equipment with power cord connected to outlets
(household appliances, portable tools, etc.)

Note：BRINGO is a registered trademark of IWATSU ELECTRIC CO., LTD.

* Accuracy: ±(X% of reading + Y digits) is written as X + Y. Accuracy for all is 1 year after calibration.

DC voltage measurement (DCV)
CH-B DC voltage measurement (DCV)　
*Equipped only with VOAC7523H/7520H
AC voltage measurement (ACV, DC + ACV) True RMS value detection
DC current measurement (DCA)
AC current measurement(ACA, DC+ACA)
Resistance measurement(2WireΩ/4WireΩ)
Lo-Power resistance measurement (2WireΩ)ireΩ)
Diode measurement
Temperature measurement
Frequency measurement

Typical sample rate and resolution
Combination of dual functions
General performance
FAQ

DC voltage measurement (DCV)

Range	Resolution		Input resistance	Accuracy *
Range	5.5-digit	4.5-digit	Input resistance	SLOW/MID	FAST
50mV	0.1µV	1µV	100MΩ or more	0.025+10	0.025+15
500mV	1µV	10µV	1000MΩ or more	0.012+5	0.012+10
5V	10µV	100µV	1000MΩ or more	0.012+2	0.012+7
50V	100µV	1mV	Approx. 10MΩ	0.016+5	0.016+10
500V	1mV	10mV		0.016+2	0.016+7
1000V	10mV	100m		0.016+2	0.016+7

The 50mV range is VOAC 7523H/7522H only
50mV and 500mV ranges are accurate after zero correction by REL calculation
Sample rate of 50mV range is SLOW/MID：approx. 0.5 times/second, FAST：approx. 50 times/second
Maximum allowable voltage
50mV to 5V ranges ±800V continuous
50V to 1000V range ±1100V continuous

Resolution and noise rejection

Resolution	Sample rate	NMRR	CMRR
5.5-digit	SLOW	55dB or more	120dB or more
5.5-digit	MID	55dB or more	120dB or more
4.5-digit	FAST	0dB	55dB or more

CH-B DC voltage measurement (DCV)　Equipped only with VOAC7523H/7520H

Range	Resolution	Input resistance	Accuracy *
Range	4.5-digit	Input resistance	SLOW/MID	FAST
5V	100µV	CH-B：H～CH-B：L　10MΩ±3% CH-B：H～CH-A：L　 5MΩ±3% CH-B：L～CH-A：L　　5MΩ±3%	0.025+2	0.025+30
50V	1mV			0.025+8
300V	10mV			0.025+5

Maximum allowable voltage：±300V, ±300V between CH-A L and CH-B

Resolution and noise rejection

Resolution	Sample rate	NMRR	CMRR	Influence of voltage between CH-A and L
4.5-digit	SLOW/MID	120dB or more	120dB or more	56dB or more
4.5-digit	FAST	0dB	55dB or more	56dB or more

AC voltage measurement (ACV, DC + ACV) True RMS value detection

Range	Resolution	Measurement range		Input resistance
Range	5.5-digit	SLOW	MID/FAST	Input resistance
500mV	1μV	15Hz～300kHz *	200Hz～300kHz *	Approx. 1MΩ// 100pF or less
5V	10μV
50V	100μV
500V	1mV	45Hz～100kHz	200Hz～100kHz
750V	1mV	45Hz～20kHz	200Hz～20kHz

VOAC 7521H/7520H up to 100kHz

Accuracy：SLOW/MID/FAST sample

Frequency	Accuracy *
15Hz～45Hz	0.5+150
45Hz～100Hz	0.25+150
100Hz～30kHz	0.2+150
30kHz～100kHz	0.5+300
100kHz～300kHz	2.5+1000

For sine waves from 5% to 100% of the range

Coefficient for inputs other than sine waves

Frequency	Crest factor
Frequency	1～1.5	1.5～2	2～3
15Hz～30kHz	0.05%	0.15%	0.30%
30kHz～300kHz	0.20%	－	－

Response time

Sample rate	Resolution	Measurement count	Response time
SLOW	5.5-digit	4 times/second	3 seconds or less
MID/FAST	5.5-digit	20 times/second	2 seconds or less

Maximum allowable voltage：780Vrms, ±1100VDC (continuous)
For DC + ACV, add 500 (45Hz or less) or 300 (45Hz or more) to the accuracy digits.
The sample rate FAST is the same as MID approx. 20 times/second.

DC current measurement (DCA)

Range	Resolution		Accuracy *		Input resistance
Range	5.5-digit	4.5-digit	SLOW/MID	FAST	Input resistance
5mA	10nA	100nA	0.05+7	0.05+17	150Ω or less
50mA	100nA	1µA			15Ω or less
500mA	1µA	10µA			2Ω or less
10A	100µA	1mA	0.2+7	0.2+17	0.1Ω or less

The input terminals of the 5mA to 500mA range and the 10A range are different, so the automatic range between them is not performed.
Maximum allowable current
5mA to 500mA range：500mA (FUSE 0.5A/250V)
10A range：10A (FUSE 15A/250V)

AC current measurement(ACA, DC+ACA)

Range	Resolution	Measurement range		Input resistance
Range	5.5-digit	SLOW/MID	FAST	Input resistance
5mA	10nA	15Hz～5kHz	200Hz～5kHz	150Ω or less
50mA	100nA	15Hz～5kHz		15Ω or less
500mA	1µA	45Hz～5kHz		2Ω or less
10A	100µA	45Hz～5kHz		0.1Ω or less

Accuracy：SLOW sample

Frequency	Accuracy *	Crest factor
Frequency	Accuracy *	1～1.5	1.5～2	2～3
15Hz～45Hz	1+200	0.05%	0.15%	0.30%
45Hz～1kHz	0.4+200
1kHz～5kHz	5.0+200

5% to 100% of range for 5mA/50mA/500mA ranges, 10% to 100% of range for 10A range

Response time

Sample rate	Resolution	Measurement count	Response time
SLOW	5.5-digit	4 times/second	3 seconds or less
MID/FAST	5.5-digit	20 times/second	2 seconds or less

Maximum allowable current
5mA to 500mA range：500mA (FUSE 0.5A)
10A range：10A (FUSE 15A)
Observe the maximum allowable current, including the DC component superimposed on the input current.
For the 10A range, 45 Hz to 1 kHz, add 0.3 to the % term.
For DC+ACA, add 500 (below 45Hz) and 300 (above 45Hz) to the digits of accuracy term.
The sample rate FAST is the same as MID approx. 20 times/second.

Resistance measurement(2WireΩ/4WireΩ)

Range	Resolution		Accuracy *		Measured current
Range	SLOW/MID	FAST	SLOW/MID	FAST	Measured current
50Ω	0.1mΩ	1mΩ	0.025+10	0.025+15	Approx.10mA
500Ω	1mΩ	10mΩ	0.014+3	0.014+8	Approx.10mA
5kΩ	10mΩ	0.1Ω			Approx.1mA
50kΩ	0.1Ω	1Ω			Approx.100μA
500kΩ	1Ω	10Ω	0.015+3	0.015+33	Approx.10μA
5MΩ	10Ω	10Ω	0.033+30	0.033+30	Approx.1μA
50MΩ	100Ω	100Ω	0.25+30	0.25+30	Approx.100nA
500MΩ	1kΩ	1kΩ	1.5+50	1.5+50	Approx.10nA

4WireΩ is VOAC 7522H/7521H only
Maximum allowable voltage：± 500Vpeak
Terminal open voltage: 12V or less
The range of 50Ω to 5kΩ is the accuracy after zero correction by the REL operation.
FAST in the 5MΩ to 500MΩ range is the same as MID, approx. 20 times/second.

Lo-Power resistance measurement (2WireΩ)

Range	Resolution	確Accuracy *		Measured current
Range	SLOW/MID/FAST	SLOW/MID	FAST	Measured current
500Ω	10mΩ	0.1+5	0.1+15	Approx. 1mA
5kΩ	0.1Ω			Approx.100µA
50kΩ	1Ω			Approx.10µA
500kΩ	10Ω	0.2+30	0.2+40	Approx.1µA
5MΩ	100Ω	0.2+30	0.2+30	Approx.100nA
50MΩ	1kΩ	1.5+30	1.5+30	Approx.10nA

Maximum allowable voltage：± 500Vpeak
Terminal open voltage：12V or less
The range of 500Ω to 5kΩ is the accuracy after zero correction by the REL operation.
FAST in the 5MΩ to 50MΩ range is the same as MID, approx. 20 times/second.
SLOW/MID/FAST are all 4.5 digits.

Diode measurement

Measured current	Measurement range	Accuracy *	Terminal open voltage	Maximum allowable voltage
Approx. 1mA or 10mA	0.1mV～5.0999V	0.014+13	12V or less	±500Vpeak

Temperature measurement

Thermocouple	Measured temperature range	Accuracy *	Resolution	Maximum allowable voltage
R	-50～0℃	0.2+70	0.1℃	±500Vpeak
	0～+100℃	0.2+50
	+100～+1,768℃	0.2+30
K(CA)	-200～-100℃	0.15+50
	-100～0℃	0.15+35
	0～+1,372℃	0.15+20
T(CC)	-200～-100℃	0.15+50
	-100～0℃	0.15+35
	0～+400℃	0.15+20
J(IC)	-200～-100℃	0.15+50
	-100～0℃	0.15+35
	0～+1,200℃	0.15+20
E(CRC)	-200～-100℃	0.15+50
	-100～0℃	0.15+35
	0～+1,000℃	0.15+20

The above accuracy does not include the accuracy of the thermocouple.
Add ±0.1°C/°C for all thermocouples at the operating ambient temperature of 0°C to +18°C and +28°C to +50°C.
The measured temperature -200°C or less may be displayed, but the accuracy is not guaranteed.
The reference thermoelectric power is calculated according to the broken line approximation according to JIS C 1602-1995.
When the device and the thermocouple are connected through a plug, the error of the contact temperature compensation is added.
After connecting the thermocouple, heat run the unit for at least 1 hour. Do not expose the unit to wind.

Frequency measurement

Sample rate	Measurement count (gate time)	Number of digits to display and measurement range		Accuracy *
SLOW	Approx. 0.5 times/second (1s)	6-digit	15.0000Hz～1.00000MHz	0.02+2
MID	Approx. 4 times/second (100ms)	5-digit	15.000Hz～1.0000MHz
FAST	Approx. 10 times/second (10ms)	4-digit	150.00Hz～1.000MHz

AC coupling, Crest factor：3 or less
Input attenuator uses ACV AUTO range.
Maximum allowable voltage：780Vrms, ±1100Vpeak

Typical sample rate and resolution

Sample rate	Resolution	Measurement count	Hum rejection
SLOW	5.5-digit	Approx. 4 times/second	○
MID	5.5-digit	Approx. 20 times/second	○
FAST	4.5-digit	Approx. 100 times/second	×

Combination of dual functions

In the table, the number on the right shoulder of the△ mark indicates the corresponding “Constraint” number.
CH-B DCV is only installed on VOAC7520H/7523H.
4WΩ is only installed on VOAC7521H/7522H.

Dual-function operation has the following limitations compared to single-function operation.

You cannot select a sampling rate.
The sampling rate will be delayed. (For example, in the case of a dual function with a combination of DCV and DCA, the limit is about 1 time/second. Please contact us for more details.)
The display does not show the results of comparator operations, the type of statistical data, or attribute information such as functions, ranges, and timestamps.
The main unit of measurement is not displayed. The units of measurement of the sub-side are displayed with the LED of “SUB DISP UNITS.”

General performance

		Specification
Operations		Moving average, scaling operations, decibel operations (dBm, dBµ), differential operations, statistical operations (MAX, MIN, x, σ), comparison operations, dual function arithmetic operations, continuity tests
Memory	DATA	3000pcs data with 10msec resolution timestamp (elapsed time)
Memory	SET UP	10 pieces
Interface (Full remote)	Standard	RS-232
Interface (Full remote)	Option	LAN, GP-IB
Power supply	Voltage	AC100V (standard) Can be changed to 110V, 220V, or 240V　*Additional modification costs are required.
	Frequency	50Hz, 60Hz
	Power consumption	21VA or less (including option)
Operating temperature and humidity		0°C to +50°C (80% rh or less) Less than 70%RH at +40°C to +50°C no condensation
Storage temperature and humidity		-20°C to 0°C, +40°C to +60°C (70%RH or less) 0°C to +40°C (80% rh or less) no condensation
Size	Shape	210Wx99Hx353L mm (Optionally built into the main unit)
Size	Weight	3.5kg or less (including option)
Accessories		Current measurement spare fuse (2 each of 2 kinds), Test leads (1 set), Adjustment screwdriver (1), Simple manual (1), Instruction manual (CD-ROM) (1), AC power cable(1)

FAQ

Please click below for FAQs regarding this product.If your questions are not resolved by the FAQs, please contact us via email using the “Inquiries” link above.

FAQ

Measurement cable length：90cm Wire diameter that can be pinched：Approx. Φ6mm
Detailed dimensions of the clip are here.