The 4–20 mA analog proximity sensor gives the same continuous distance measurement as the voltage version, but transmits it as a current loop — the standard that industrial instrumentation has used for decades precisely because it survives long cables and electrical noise.
Why a current loop beats a voltage signal
A voltage signal degrades along a cable: conductor resistance creates a drop that shows up directly as measurement error, and nearby drives and contactors couple noise straight into the reading. A current loop has neither problem. The same current flows at every point in the loop regardless of length or conductor resistance, and current signals are far less susceptible to induced interference.
There is a diagnostic benefit too. Because a healthy loop never reads below 4 mA, a reading of 0 mA can only mean a broken cable or dead sensor — a distinction the 0–10 V version cannot make, since 0 V is a valid measurement.
How the scale maps
- 4 mA corresponds to the minimum sensing distance (8 mm).
- 20 mA corresponds to the maximum sensing distance (15 mm).
- Output moves linearly between the two across the working window.
Key features
- Linear 4–20 mA current output proportional to target distance.
- No signal loss over long cable runs — unaffected by conductor resistance.
- Immune to electrical noise from motors, drives and contactors.
- Works with PLCs, SCADA systems and data loggers accepting standard current inputs.
- 200 Hz switching frequency for dynamic applications.
- IP68 chrome-plated brass housing, short-circuit and reverse-polarity protected.
- Non-flush mounting allows side sensing.
Technical specifications
| Parameter | Value |
|---|---|
| Output signal | 4–20 mA, linear |
| Sensing range | 8 mm to 15 mm |
| Hysteresis | 5–10% of sensing distance |
| Repeatability | 5–10% of sensing distance |
| Operating voltage | 10–30 V DC |
| Switching frequency | 200 Hz |
| Protection class | IP68 |
| Housing material | Chrome-plated brass |
| Mounting type | Non-flush |
| Short-circuit protection | Yes |
| Reverse-polarity protection | Yes |
| Status indication | LED |
| Standard cable | 2 m (custom lengths on request) |
Typical applications
- Industrial automation — position monitoring and object detection over long cable runs.
- Process control — liquid level and thickness measurement.
- Machine safety and feedback systems reporting to a central SCADA.
- Conveyor belt and robotic guidance where drives generate electrical noise.
How to order
Tell us the sensing gap, the target material, your supply voltage and the output type your controller needs. If you are replacing an existing sensor, a photograph of the body markings is usually enough for us to identify an equivalent. We will confirm the specification and quote — normally the same day.
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Frequently asked questions
How long a cable run can I use with 4–20 mA?
Far longer than with a voltage output — hundreds of metres is routine in process plants. The practical limit is set by the loop supply voltage against total loop resistance, so for very long runs tell us the distance and supply voltage and we will confirm.
Can I convert 4–20 mA to a voltage at the panel?
Yes. A precision resistor across the input converts the current to a voltage — 250 Ω gives 1–5 V. Many analog input cards do this internally when you select current mode.
Need a quote for the 4–20 mA Analog Proximity Sensor?
Send us your application — target material, sensing distance, supply voltage and housing constraint. We will recommend a part, quote it, and ship from Mumbai.