Can a laser distance module output 4–20 mA?
Not ours, and not most board-level ranging modules. If you are wiring a distance sensor into a PLC rack or a panel meter that expects a current loop, the honest answer is: the module speaks UART-TTL, and the 4–20 mA loop is something you add — either with a small converter or with a controller that reads the module and drives the loop.
This page is for the engineer who has already found that out and needs to know which way to go, and for the buyer who wants to avoid ordering the wrong thing. We would rather lose a line than ship a module into an analog input it cannot drive.
What the modules actually output
| Interface | Status in our catalogue | What it means for you |
|---|---|---|
| UART-TTL | Every module we ship, as standard | Distance arrives as a frame with a checksum. You need a UART on the host side — a PLC serial card, a microcontroller, or a converter. |
| I²C | One model only | Useful for tight microcontroller boards; not a catalogue-wide option. |
| RS232 / RS485 | Not a native option — host-side transceiver, or a factory variant confirmed per order | RS485 is usually about cable length and noise, not about the module. A TTL-to-RS485 transceiver at the module end solves it. |
| 4–20 mA / 0–10 V | Not available natively | Needs a converter or a controller that writes the loop. Details below. |
If your requirement is a cased sensor with an analog output already inside, that is a different product class — a complete industrial instrument rather than a board-level OEM part. We do not sell that, and pretending otherwise wastes your time.
Three ways to get a current loop, in order of how often they are the right answer
1. Controller reads the module, controller drives the loop. The most common and the most flexible. A microcontroller or a PLC with a serial port reads the distance frame and writes a 4–20 mA loop transmitter or a DAC channel. You get to define scaling, clamping, fault behaviour and filtering in software, which is where those decisions belong.
2. Serial-to-analog converter module. An off-the-shelf converter takes the UART frame and outputs 4–20 mA. Fewer parts to design, but you inherit the converter’s fixed scaling and its update rate. Check three things before buying one: the baud rate it accepts, whether it can parse your frame (many only parse a bare number), and what it outputs when the module stops answering.
3. A cased industrial sensor with a built-in analog output. Correct when you are instrumenting a machine and want one box, one cable, one datasheet. You pay for the housing, the certification and the support, and you lose the ability to put the sensing head where the geometry needs it.
The engineering details that decide whether it works
- Fault behaviour. A 4–20 mA loop carries no error code. Decide in advance what happens when the module returns a bad frame, a timeout, or a target that is out of range: hold the last value, clamp to 21 mA, or drop to 3.6 mA. NAMUR NE43 convention (3.8 mA / 20.5 mA as fault levels) is the usual reference — follow whatever your control system expects, but decide it explicitly.
- Resolution versus range. A 16-bit loop writer over 0–3,000 m gives you roughly 5 cm per count, so the loop, not the module, becomes your accuracy floor. If you need centimetre accuracy at 3 km, keep the serial link and put the number on a display instead.
- Update rate. The module may range at 100 Hz or more; a 4–20 mA loop through a PLC analog input typically updates far slower. If you are closing a loop on distance, use the serial path and let the analog output serve monitoring only.
- Isolation and grounding. A loop powered from the panel and a module powered from the machine can sit at different ground potentials. Isolate the transmitter side, keep the module’s supply clean, and do not assume the shield is a conductor.
- Scaling. Define the mapping in writing (e.g. 4 mA = 0 m, 20 mA = 3,000 m) and put it in the machine documentation. Six months later, nobody remembers whether 12 mA meant 1,500 m.
What we give you to make this fast
- The serial frame and checksum, so a converter or a script can parse it correctly.
- UART-TTL integration guide — levels, wiring, common mistakes.
- Reading the module with Arduino over UART — a working starting point for path 1.
- Pinout and wire colours.
- Model pages with interface, supply voltage, update rate and the price ladder for every model.
Tell us the loop supply, the PLC input card and the update rate you need, and we will tell you which of the three paths fits and which model to start with — tommy@erdimail.com, one working day (Chengdu, UTC+8).
Related reading: HS code and import declaration elements · Board-level module vs cased industrial sensor