
Autonics BL13-TDT Photoelectric Sensor
Autonics BL13-TDT Liquid Level Photoelectric Sensor for Transparent Pipes (Ø6–13 mm, NPN/PNP, IP64)
Compact liquid level photoelectric sensor for detecting the presence/absence of liquid inside transparent or semi-transparent pipes.
Ideal for coolant lines, water pipes, and chemical dosing systems in compact industrial machinery.
The Autonics BL13-TDT is a liquid level photoelectric sensor designed to detect the presence or absence of liquid inside transparent or semi-transparent pipes using the refractive index principle of light. Its compact size, non-contact detection, and easy installation make it ideal for coolant pipes, water supply lines, and chemical dosing equipment where float-type sensors are not suitable.
Key Features
Detects liquid in transparent/semi-transparent pipes
Applicable pipe diameter: Ø 6–13 mm (1 mm thickness)
Non-contact detection using refractive index of light
Light-ON / Dark-ON selectable via push button
NPN & PNP open-collector output (model dependent)
Operation indicator (Red) & mode indicator (Green)
Built-in reverse power & output short-circuit protection
Compact design for tight installation spaces
IP64 protection rating (IEC)
Cable type, easy pipe mounting using binding bands
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | BL13-TDT |
| Sensor Type | Liquid Level Photoelectric |
| Sensing Method | Through-beam (Refractive index) |
| Applicable Pipe | Ø 6–13 mm transparent pipe |
| Sensing Target | Liquid in pipe |
| Response Time | ≤ 2 ms |
| Light Source | Infrared LED |
| Peak Wavelength | 950 nm |
| Output Type | NPN/PNP open collector |
| Output Mode | Light-ON / Dark-ON (button selectable) |
| Supply Voltage | 12–24 VDC ±10% |
| Load Current | ≤ 100 mA |
| Current Consumption | ≤ 30 mA |
| Protection Rating | IP64 |
| Operating Temperature | 10 to 55 °C |
Applications
Coolant level detection in CNC & machines
Water flow presence detection
Chemical dosing & liquid pipelines
Beverage & liquid processing machines
Medical & laboratory equipment
Compact OEM automation systems
What’s in the Box?
Autonics BL13-TDT Liquid Level Sensor
Binding bands × 2
Anti-slip tubes × 2
Instruction manual
FAQ
Q1. What pipe sizes are supported?
Transparent pipes with a 6–13 mm diameter and approx. 1 mm thickness.
Q2. Does the sensor touch the liquid?
No. It is a non-contact liquid detection sensor.
Q3. Can it detect all liquids?
It may not detect low-transparency, high-viscosity liquids or liquids with floating particles.
Q4. Is Light-ON / Dark-ON selectable?
Yes, selectable using the operation mode switching button.
Q5. Is it suitable for industrial environments?
Yes, it has IP64 protection and built-in protection circuits.



