1. What is 4-20 mA Signal?

The 4-20 mA current loop is a common industrial standard for transmitting sensor information and control signals. The 4 mA represents the zero or minimum scale value, while 20 mA represents the full scale or maximum value.

2. How Does the Calculator Work?

The calculator uses the conversion formula:

Where:

• \( mA \) — Current value in milliamps (between 4-20 mA)
• 4 — Zero scale reference (0%)
• 16 — Span between minimum and maximum (20-4 = 16)
• 100 — Conversion to percentage

Explanation: This linear conversion scales the 4-20 mA signal range to a 0-100% proportional representation.

3. Importance of 4-20 mA Conversion

Details: Converting 4-20 mA signals to percentage values is essential for process monitoring, control systems, and instrumentation calibration in industrial applications.

4. Using the Calculator

Tips: Enter the current value in mA between 4 and 20. The calculator will automatically compute the corresponding percentage value from 0% to 100%.

5. Frequently Asked Questions (FAQ)

Q1: Why is 4 mA used instead of 0 mA?
A: The 4 mA "live zero" allows distinction between a zero signal (4 mA) and a broken wire or failed sensor (0 mA).

Q2: What if my mA value is below 4 or above 20?
A: Values outside the 4-20 mA range typically indicate sensor malfunction, wiring issues, or measurement errors.

Q3: Can this formula be used for reverse calculation?
A: Yes, to convert percentage back to mA: \( mA = (Percentage / 100) \times 16 + 4 \)

Q4: Are there different industrial standards?
A: While 4-20 mA is most common, some applications use 0-20 mA, 0-5V, or 0-10V signals depending on specific requirements.

Q5: How accurate is this conversion?
A: The conversion is mathematically exact. Accuracy depends on the precision of your current measurement equipment.