What is voltage measurement? A systematic introduction to voltage sample devices.
1.What is voltage?
Voltage is the potential difference between two points in an electrical or electronic circuit. In other words, it is the energy required to move an electric charge from one point in a circuit to another. Its unit in the International System of Units (SI) is the volt (V). Voltage is a scalar quantity, a difference in electric potential, and one of the most fundamental physical quantities. Voltage is ubiquitous in our lives. For example, various household appliances operate on 220V AC power, and electronic devices such as mobile phones and tablets use chargers to convert 220V AC power into 5V, 12V, or other DC power for charging. Therefore, voltage is divided into direct current (DC) and alternating current (AC) based on the direction of current flow.
Direct current (DC) has a constant current magnitude, flowing from positive to negative. Due to its high stability, it is commonly used in battery-powered applications, electronic circuits, and precision control. Alternating current (AC) has a constantly changing current magnitude and direction. It is the standard electricity output from a power outlet and can efficiently transmit power. It is mainly used in power transmission and distribution, motor drives, and other fields, such as powering homes and factories. In industrial design, it is often necessary to convert between DC and AC. The method of DC-AC conversion depends on the components and design of the circuit.
2.The Relationship Between Voltage Signals and Analog and Digital Quantities
In the fields of electronics and information processing, analog and digital quantities are two fundamental signal types. Analog quantities refer to continuously changing physical quantities that can take on an infinite number of values within a certain range, such as common quantities like temperature, pressure, humidity, and vibration. Voltage is also an analog quantity. Digital quantities, on the other hand, are discrete, discontinuous signals, usually represented in binary. Most physical quantities encountered in daily life are analog signals, but computers can only process electrical signals like 0101. Therefore, analog-to-digital converters (ADC) are needed to convert these analog signals into electrical signals for transmission to the computer, facilitating high-speed processing and long-term storage.
Currently, there are two methods for measuring voltage: one is measuring the voltage signal output by a sensor, and the other is measuring circuit voltages such as power supply voltage. This article mainly focuses on the first method.
3.Sensor output type
A sensor is a monitoring device that converts information about a measured object into electrical signals or other forms of output according to a certain rule.
Sensors can be classified by function into: temperature sensors, humidity sensors, pressure sensors, displacement sensors, acceleration sensors, torque sensors, etc. Sensor output signals come in various forms, but in practical systems, these signals are usually conditioned or converted into standard analog voltage or current signals for acquisition and processing. For example, the thermocouple sensor we discussed earlier uses the Seebeck effect to convert temperature changes into voltage signal changes; resistance strain gauges convert changes in resistance caused by force into voltage signal changes via a Wheatstone bridge; piezoelectric accelerometers convert changes in charge caused by acceleration into voltage signal changes, and so on.
These sensors, whose output is a voltage signal, play an important role in various industries. They convert the measured physical quantity into a proportional voltage signal, with common voltage ranges including 0-5V and 0-10V. Therefore, their monitoring and analysis have become essential means to ensure the performance and safety of related systems.
Voltage is one of the most commonly used and fundamental input types for data acquisition equipment. In principle, voltage output sensors that meet the input specifications of the data acquisition device can be directly connected for measurement. However, in practical applications, the signal input method needs to be determined based on the specific scenario and requirements. A voltage data acquisition unit is a core device specifically designed for acquiring these analog voltage signals.
4.Working principle of voltage sample device
A voltage acquisition unit is a device specifically designed for measuring and acquiring voltage signals. It converts analog voltage signals into digital signals, which are then transmitted to a computer or data processing system for display, recording, and analysis.
For acquiring voltage signals output from sensors, KETU&TEST has developed the KTVS-32A voltage sample device. Its working principle can be simply summarized as: analog signal → ADC chip → digital processing → external communication transmission.
First, multiple input interfaces receive analog voltage signals from external sensors. These signals undergo conditioning circuitry, including electrical isolation protection, programmable amplification, and anti-aliasing filtering, to ensure signal stability and remove noise. Then, the analog-to-digital converter (ADC) converts the analog signals into digital signals, synchronously converting all signals under a unified sampling clock. The converted digital data is transmitted to the core processing unit via a high-speed bus. The processor built into the core board further processes these signals, and the processed data is stored in the built-in memory card and transmitted to external devices or platforms via interfaces such as TCP/IP for real-time monitoring and data recording and analysis.
5.The model introduction voltage sample device
Taking the KTVS-32A voltage sample device from KETU&TEST as an example, it features 32 independent, electrically isolated synchronous acquisition channels, allowing selection of both ±5V and ±10V voltage signal ranges. The acquisition accuracy reaches ±0.05%FS, with a single channel sampling rate of 10kHz.
Regarding power supply, the device supports both external power and built-in battery power. In the event of an external power outage, it automatically switches to battery power, ensuring at least 6 hours of independent operation. It can also provide a 9-24VDC voltage excitation source for external sensors, significantly improving the efficiency of on-site measurements.
In terms of data acquisition, the device has a built-in memory card to store acquired data. It also features offline buffering and reconnection retransmission functions to ensure data is not lost in the event of disconnection or communication failure. Furthermore, a synchronous clock mechanism is designed between the system and channels to ensure absolute time synchronization of all channels. It supports software triggering and 3.3V hardware triggering, providing accurate data support for dynamic testing and real-time monitoring.
Regarding communication, the device supports the TCP/IP communication protocol. Through a flexible interface design, it can seamlessly interface with external control systems and data platforms, facilitating remote control and data transmission. Furthermore, the KTVS-32A features online hardware upgrade capabilities, allowing users to upgrade and expand its functionality via network or other interfaces without disassembling the device, offering convenience and efficiency.
In a word, understanding voltage measurement is a crucial foundation for mastering the working principles of voltage acquisition equipment. As a key measurement tool in modern industry, voltage sample devices, with their stable and reliable performance, widely support testing needs across various stages of R&D, production, and maintenance. KETU&TEST will continue to focus on innovation and breakthroughs in measurement technology, providing customers in various fields with more advanced and reliable test and measurement solutions.
