ABB NTU-7A4/20MA NTU-7A4 Millivolt Converter

ABB NTU-7A4/20MA NTU-7A4 Millivolt Converter

Basic information

Model and name: ABB NTU - 7A4/20MA and NTU - 7A4 Millivolt Converter, both models are related to signal conversion. NTU - 7A4’ is the basic model number, mainly used to convert millivolt signals to other signals (such as 4 - 20mA current signals), in the industrial automation control system to play the role of signal conditioning and conversion.

Series: ABB Signal Conditioning Modules for Industrial Automation are part of the ABB Signal Conditioning Modules series. In this series, there are other types of signal converter modules, input/output modules, communication modules, etc., which cooperate with each other to form a complete signal processing system for industrial automation.

Application Scenario Connection: Widely used in process control systems in industrial sites, especially in chemical, electric power, metallurgy and other industries. It is used to connect various sensors (e.g. thermocouples, etc.) that output millivolt signals, convert the millivolt signals into current signals that are easier to transmit and process, and then transmit them to controllers or other monitoring devices to achieve the monitoring and control of industrial process parameters (e.g. temperature, pressure, etc.).

Functional features

Signal Conversion Functions

Millivolt-to-current conversion: The main function is to accurately convert millivolt signals to 4 - 20mA current signals. In industrial sensors, many sensors (e.g. thermocouples) output weak signals in the millivolt range, which are susceptible to interference over long distances. The NTU-7A4 module converts these signals to a 4-20mA current signal, which is highly resistant to interference and maintains signal accuracy over long distances, ensuring reliable monitoring of industrial process parameters.

Highly accurate conversion: With high conversion accuracy, it can accurately convert millivolt signals into corresponding current signals. Conversion accuracy may range from ±0.1% - ±0.5%, depending on module design and calibration. For example, for a sensor signal with an output of 10mV, the module can accurately convert it to a current signal in the range of 4 - 20mA within the permissible error, providing an accurate input signal for industrial control systems.

Signal Conditioning Functions

Linearisation: For sensor signals with non-linear outputs (e.g. some thermocouples have non-linear temperature-millivolt characteristics), the module can perform linearisation. Through the built-in linearisation algorithm or calibration data, the non-linear millivolt signal is converted to a 4 - 20mA current signal that is linear with the measured physical quantity (e.g. temperature), which is convenient for the control system to carry out subsequent operations and processing.

Signal amplification and filtering: The input millivolt signal may be suitably amplified to increase the signal strength for subsequent conversion and transmission. At the same time, the module may also have a filtering function, which can remove the high-frequency noise and interference components in the signal, so that the output 4 - 20mA current signal is more pure and stable, and reduce signal distortion.

Compatibility and Interface Features

Compatible with a variety of millivolt signal inputs: Compatible with a variety of ranges of millivolt signal inputs, for example, it can receive signals from a few millivolts to hundreds of millivolts, in order to adapt to different types and ranges of sensors. This makes it possible to flexibly connect sensors with various millivolt signal outputs, such as thermocouples of different materials and types, in industrial sites.

Standard Current Output Interface: The 4 - 20mA current output signal conforms to industrial standards and can be easily connected to the analogue input ports of various industrial controllers, recorders, indicators and other devices. These devices are usually equipped with the ability to receive and process 4 - 20mA current signals, thus enabling seamless signal interfacing and system integration.

Technical Parameters

Electrical Parameters

Operating voltage range: The operating voltage is generally DC voltage, the range may be around 18V - 30V DC, which can adapt to the common power supply situation in the industrial field, to ensure that the module can work stably under different power conditions.

Input millivolt signal range: the millivolt signal range is wide, for example, it may be - 10mV - + 100mV or other ranges determined according to the specific model to adapt to the output signal of different sensors. At the same time, the module has a low power consumption for the input signal to avoid a large impact on the sensor signal.

Output Current Signal Characteristics: The output 4 - 20mA current signal can remain stable within a certain load range, for example, it can work normally within the range of 0 - 500Ω load resistance, which ensures that it can provide accurate signals when connecting to different receiving devices.

Power Consumption: Low power consumption, usually between a few watts and a dozen watts, depending on the module's operating conditions (e.g., frequency of signal conversion, strength of the input signal, etc.) and the module's design. The low power consumption design helps to run stably for a long time in industrial environments, and it can reduce the heat of the equipment and improve the reliability of the equipment.

Performance Parameters

Conversion accuracy: As mentioned above, the conversion accuracy may be between ±0.1% - ±0.5%, and may also have a resolution and other performance indicators, such as for millivolt signals converted to current signals can reach a resolution of 0.01mA - 0.1mA, which determines the minimum amount of signal change can be distinguished.

Linearity: For the linearised signal, the linearity is high, for example, the linearity error may be between ±0.1% - ±0.3%, to ensure that the output of the 4 - 20mA current signal and the measured physical quantities of the linear relationship between the accuracy of the control system to facilitate the calculation and processing.

Response time: With a short response time, it can quickly convert the input millivolt signal and output the corresponding current signal. Response time is generally in the milliseconds, for example, a typical response time may be between 1ms - 10ms, which ensures that the sensor signal can be converted and transmitted in a timely manner, to meet the real-time requirements for signal monitoring in industrial processes.