PlantFlow 3D › Simulators › 4–20 mA Loop Simulator and Calculator for instrumentation
4–20 mA Loop Simulator and Calculator for instrumentation
Simulate a 4–20 mA instrument loop: scaling, NE 43 fault currents, loop power budget, calibration points and Pt100 tables. Free for students and technicians.
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What it is
A 4–20 mA loop carries a measurement as a current: 4 mA is 0 % and 20 mA is 100 % of the range. PlantFlow 3D lets you convert between current and engineering units, check the NAMUR NE 43 fault limits, calculate the voltage left for a two-wire transmitter and print five-point calibration sheets.
What you can do
- Convert mA to engineering units and back for any range.
- See healthy, under-range and over-range signal states (NE 43).
- Calculate the loop power budget: supply, barrier, cable and input resistance.
- Pt100 resistance and temperature (IEC 60751 coefficients).
- Use the level transmitter LT-101 and the control valve FV-101 in the process model.
How to use it
- Open Tools → 4–20 mA & RTD with the button below.
- Enter the range of your transmitter.
- Read the 0, 25, 50, 75 and 100 % calibration points.
- Open Tools → Calculators for the step-by-step formulas.
Learn the theory
- 4–20 mA current loops for beginners
- Instrument loop diagrams and cable screens
- Reading P&ID instrument tags
- PLC ladder logic basics
Questions
What does a reading below 3.8 mA mean?
Under NAMUR NE 43 it is treated as a failure, for example a broken loop or a faulty transmitter.
Is 4–20 mA scaling linear?
Yes: value = LRV + (mA − 4) / 16 × (URV − LRV).
Safety: this guide explains principles for learning. Real installations must follow the applicable codes, the equipment manufacturer's instructions and the approval of a competent, qualified person. Isolate, lock off and prove dead before touching any circuit.