Submersible Level Transmitter: Installation and 4–20 mA Wiring
Send the tank or well depth, liquid and cable length — we confirm the range and cable and quote samples.
This 3:09 video shows how to install and wire a submersible level transmitter: where to place the probe, when to use a stilling pipe, how to keep the vent tube open, 2-wire 4–20 mA wiring to a PLC, scaling the signal on a 0–10 m range, and what to specify before ordering.
Chapters
Key points
- The probe measures the pressure of the liquid above it; for water, 1 m is about 0.1 bar.
- A vent tube in the cable cancels atmospheric pressure; keep it open and dry and end the cable in a vented junction box.
- Use a stilling pipe in moving or turbulent liquid so the probe hangs still.
- 2-wire loop: one pair carries the 12–36 V DC supply and the 4–20 mA signal; on 0–10 m, 12 mA = 5 m.
- Range 0.5–200 mWC, ±0.1% FS standard, 316L probe rated IP68; PTFE cable for chemical media.
Transcript
Submersible level transmitters: how to install and wire them for a stable reading.
The probe sits at the bottom and measures the pressure of the liquid above it. For water, 1 m gives about 0.1 bar.
A small vent tube in the cable connects the sensor to the air, so changes in atmospheric pressure cancel out.
To install, lower the probe to the bottom of the tank or well, and keep it clear of sludge.
In moving or turbulent liquid, guide the probe in a stilling pipe so it hangs still.
Keep the vent tube open to the air and dry. End the cable in a vented junction box.
Wiring is a 2-wire loop: one cable pair carries both the 12–36 V DC supply and the 4–20 mA signal.
Connect the supply positive to the transmitter, and the transmitter's return to the analog input of the PLC.
On a 0–10 m range, 4 mA is empty, 12 mA is 5 m and 20 mA is full.
To convert: subtract 4 mA, divide by 16 mA, multiply by the range.
Specify the range (0.5–200 mWC) and the cable length: 5 m standard, or made to your installation depth.
Standard accuracy is ±0.1% FS, with a 316L stainless steel probe rated IP68.
For chemical media, a PTFE cable is available.
On the production line, sealed stainless assemblies are pressurised with air and held under water, where any leak would show as bubbles.
Housings are checked before assembly.
SEGMENsensor submersible level transmitters for OEM projects. Quotes at segmensensor.com.