In modern industrial process monitoring, reliable acquisition of measurement data plays a central role. The HW-group Sensor 4-20mA 1W-UNI has been developed to precisely convert analog current loop signals into digital measurement values. This advanced solution offers safe and galvanically isolated signal transmission, ensuring accurate data acquisition even under demanding operating conditions. With its high measuring accuracy and seamless integration into existing 1-Wire-UNI systems, this signal converter is the ideal choice for engineers and technicians seeking a reliable and scalable monitoring solution.

The proven 4-20mA signal is an international industry standard that has been used for decades to transmit analog measurement data. It enables interference-resistant and robust communication between sensors and control systems. The HW-group Sensor 4-20mA 1W-UNI uses this established technology but combines it with the advantages of digital data transmission via 1-Wire UNI. This allows users to integrate a wide range of analog measurements such as pressure, temperature, flow rate, or CO₂ concentration into modern monitoring systems.

The product range includes two variants: the Sensor 4-20mA 1W-UNI and the Sensor 4-20mA 1W-UNI Set, which additionally includes a suitable plug-in power supply. Both models are fully galvanically isolated to avoid measurement errors and possible overvoltage effects. This not only extends the service life of the system but also increases operational safety in environments exposed to electromagnetic interference—such as industrial facilities, data centers, or laboratory environments.

Another advantage is the simple integration into HW-group monitoring systems such as Poseidon2, Ares, or HWg-PWR. Through these platforms, the collected data can be read in real time via LAN, GSM, or SNMP. As a result, temperature, pressure, or level values can be visualized, evaluated, and documented at any time. Alarm notifications in the event of critical conditions are also triggered automatically—by e-mail, SMS, or cloud notification.

Technological Principles of the 4-20mA Current Loop

The 4-20mA signal has become a worldwide standard in industrial measurement technology due to its reliability and noise immunity. It enables measurement values to be transmitted over long distances without signal loss. A minimum current of 4 mA represents the zero value, while 20 mA corresponds to the maximum value. The advantage is that a line break is immediately detected because no current flows. This robust current loop technology is therefore particularly important for critical processes in plant engineering, mechanical engineering, chemical industries, and the energy sector.

The HW-group Sensor 4-20mA 1W-UNI acts as a precise adapter between these traditional 4-20mA signals and modern digital monitoring networks. It converts current loop signals into a 1-Wire UNI-compatible data protocol. As a result, values can be read not only locally but also centrally collected and processed via network or cloud. This opens up new possibilities for predictive maintenance, process automation, and energy optimization.

Technical Features and Function

The Sensor 4-20mA 1W-UNI offers a variety of technical properties that make it a highly precise and robust measuring module. It measures currents in the range of 4 to 20 mA with a resolution of 0.1 mA and a measurement accuracy of ±2%. The galvanic isolation between input and 1-Wire interface protects connected devices from voltage spikes and ensures interference-free signal transmission. The electrical separation also prevents ground loops that could otherwise cause significant measurement errors in industrial networks.

The device features two RJ11 ports, allowing multiple sensors to be daisy-chained. This is particularly useful when numerous measurement points in a facility need to be evaluated centrally. With compact dimensions of only 65 × 80 × 30 mm, the sensor can be easily installed even in confined spaces. The robust plastic housing protects the electronics against dust and moisture according to protection class IP23.

To ensure optimal adaptation to different measurement applications, the 4-20mA 1W-UNI is equipped with an 8-point calibration table. Using the optional 1W-UNI USB calibrator, individual values can be precisely set. This allows easy compensation for measurement deviations caused by the specific characteristics of the connected industrial probes. This feature is particularly valuable for CO₂, pressure, or level sensors whose output curves may vary slightly.

Compatibility and Integration

A key advantage of this sensor lies in its full compatibility with various HW-group devices, including Poseidon2, Ares, and HWg-PWR. These control and monitoring systems allow real-time data transmission via LAN, GSM, or Modbus/TCP. With the free HWg-PDMS software, recorded measurements can be visualized, analyzed, and exported directly to Microsoft Excel—ideal for technical documentation and process optimization.

Furthermore, the sensor supports integration with the SensDesk cloud portal, which offers worldwide access to all measurement data. The mobile app for Android and iOS allows convenient remote monitoring on the go. This ensures that system administrators and service technicians can respond immediately to deviations from normal operating conditions.

Industrial Applications

The HW-group Sensor 4-20mA 1W-UNI is ideally suited for diverse industrial scenarios. In server rooms and data centers, it reliably measures values such as temperature, pressure, air quality, or CO₂ concentration. The collected data helps optimize climate conditions, regulate energy use efficiently, and ensure the safe operation of critical infrastructures.

In production environments, the sensor can be used to monitor tank fill levels, hydraulic pressures in pipelines, or process control parameters. Thanks to the standardized 4-20mA interface, nearly all common industrial sensors can be connected. Especially in combination with HWg-PWR, it enables precise energy monitoring, including real-time measurement of power consumption and process parameters.

The sensor also finds applications in building management—for example, in monitoring environmental conditions in heating, ventilation, and air conditioning (HVAC) systems. The galvanic isolation ensures safety and long-term reliability. Via the 1-Wire UNI interface, the sensor can be directly connected to existing monitoring systems, eliminating the need for specialized hardware.

Remote Monitoring and Alarm Functions

One of the greatest strengths of the Sensor 4-20mA 1W-UNI is its remote monitoring capability. Thanks to network connectivity, all measured parameters can be accessed on centralized platforms. In combination with Poseidon2 or Ares, automatic notifications can be configured to trigger when predefined thresholds are exceeded. Users then receive alerts via email, SMS, or push messages through the SensDesk portal, allowing immediate intervention to prevent damage—such as overheating, leakage, or pressure loss in pipeline systems.

This real-time monitoring is crucial for safety-critical applications, as it helps minimize downtime and reduce maintenance costs. It also enables predictive maintenance strategies since trends in measurement data can be detected early. This significantly enhances the reliability of production facilities and IT environments.

Energy Efficiency and Sustainability

In times of rising energy costs and strict environmental regulations, precise measurement of process parameters is essential. The Sensor 4-20mA 1W-UNI contributes to analyzing energy consumption patterns and identifying optimization opportunities. In combination with other HW-group components, comprehensive energy monitoring systems can be implemented, delivering detailed statistics. This information can be used to sustainably reduce energy usage in production facilities or office buildings.

Furthermore, the sensor contributes to environmental protection by enabling predictive maintenance. Regular condition monitoring helps avoid unnecessary downtime and inefficient operation. This not only improves resource efficiency but also enhances overall system availability.

Installation and Commissioning

Installing the sensor is straightforward and requires no special tools. The 4-20mA probe is first connected via screw terminals. The RJ11 plug is then connected to the 1-Wire UNI input of the monitoring device, such as a Poseidon2 or HWg-PWR unit. Finally, an external DC power supply (12–30 V DC) is connected to power the sensor.

After installation, measurement channels and calibration data can be configured via HW-group software or the web interface. The intuitive interface enables setup and commissioning within minutes. The optional USB calibrator allows fine-tuning of calibration, ensuring maximum measurement accuracy.

Practical Examples and Applications

In practice, the Sensor 4-20mA 1W-UNI is used in numerous fields. In data centers, it is paired with pressure or CO₂ sensors for climate monitoring. In the chemical industry, it assists in monitoring process pressures and fluid levels. For waterworks and environmental engineering companies, the combination of current loop measurement and network integration is particularly valuable for tracking parameters such as water levels, pH value, or conductivity in real time.

In the food industry, where hygienic process monitoring and temperature control are essential, the 4-20mA 1W-UNI has also proven its value. It connects seamlessly with certified process sensors, enabling continuous documentation of production conditions.

Technical Specifications Overview

• Input signal: 4–20 mA (sink type, two-wire current loop)
• Measurement range: 4 mA to 20 mA
• Resolution: 0.1 mA
• Measurement accuracy: ±2% of full scale
• Interface: 1-Wire UNI (2×RJ11 for daisy-chaining)
• Power supply: external 12–30 V DC
• Fuse: 63 mA fuse link
• Temperature range: –40 °C to +85 °C
• Humidity: 5% to 70% RH
• Dimensions: 65 × 80 × 30 mm
• Weight: 200 g
• Protection class: IP23

Available Variants

Two model variants are available:

• Variant 1: Sensor 4-20mA 1W‑UNI – galvanically isolated DC current converter for 4–20 mA signals, requires external power supply (12–30 V DC).
• Variant 2: Sensor 4-20mA 1W‑UNI Set – galvanically isolated, including plug-in power supply for external 4–20 mA probes.

The HW-group Sensor 4-20mA 1W‑UNI combines the reliability of traditional current loop technology with the flexibility of modern network monitoring. Its precise measuring accuracy, galvanic isolation, and compatibility with HW-group systems such as Poseidon2, Ares, and HWg-PWR make it a future-proof solution for industrial, IT, and building technology applications. With its easy integration into existing monitoring infrastructures and support for remote alarm systems, the sensor significantly contributes to operational safety and energy efficiency.

Whether for process control, energy monitoring, or environmental management, the Sensor 4-20mA 1W‑UNI provides a stable, precise, and flexible method for signal conversion and data acquisition. It is the ideal choice for companies seeking accurate measurement data, high safety, and long-term reliability.