Tags: current loop data logger

Remote Tank Level Monitoring Using a 4–20 mA Level Transmitter

Remote Tank Level Monitoring Using a 4–20 mA Level Transmitter

MEI 20/10/2026 0
Tank level is commonly measured with pressure, hydrostatic, ultrasonic, or other level transmitters that provide a 4–20 mA output. By connecting the transmitter to a Microedge current-input data logger, the level can be recorded continuously, converted into engineering units, and monitored locally or remotely.This Application Note shows a typical system for monitoring tank level using a 4–20 mA transmitter.  1. Application Consider a storage tank where the liquid level must be monitored continuously.Instead of checking the tank manually, a 4–20 mA level transmitter measures the liquid level and sends the signal to a data logger.A typical system consists of:Level Transmitter → 4–20 mA → Data Logger → PC / Network → Monitoring SoftwareThe system can provide:Continuous level recordingReal-time level displayHistorical graphsEngineering-unit conversionRemote monitoringAlarm monitoring when used with supported software and system configurations  2. Typical Measurement System A common two-wire 4–20 mA transmitter requires an external DC power supply.A typical loop is:24 VDC Power Supply (+) → 4–20 mA Level Transmitter → Microedge Current Input → 24 VDC Power Supply (−)The transmitter cont...
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4–20 mA Sensors and Data Loggers: Wiring, Measurement and Scaling

4–20 mA Sensors and Data Loggers: Wiring, Measurement and Scaling

MEI 20/10/2026 0
The 4–20 mA current loop is one of the most widely used signal standards in industrial measurement and process monitoring. Pressure, temperature, level, flow, humidity, and many other transmitters commonly provide a 4–20 mA output that can be recorded by a data logger or read by a control system.This Technical Note explains how a 4–20 mA signal works, how it is connected to a data logger, and how the measured current can be converted into meaningful engineering units.  1. What Is a 4–20 mA Signal? A 4–20 mA transmitter converts a physical measurement into an electrical current.Typically:4 mA represents the minimum measurement20 mA represents the maximum measurementFor example, a pressure transmitter with a range of 0–100 PSI may produce:CurrentPressure4 mA0 PSI8 mA25 PSI12 mA50 PSI16 mA75 PSI20 mA100 PSIUnlike a voltage signal, a current-loop signal is generally less affected by voltage drop in long cables, making 4–20 mA widely used in industrial environments.The 4 mA lower limit also provides a useful distinction between a valid minimum reading and certain fault conditions such as an open circuit.  2. Typical 4–20 mA Measurement System A basic 4–20 mA measurement system includes:...
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