Product Overview
The HITROL HT-100R Series continuously measures liquid level using a magnetic float that moves along a vertical guide tube.
As the float follows the liquid surface, its internal magnet activates a series of reed switches and resistors. The resulting resistance change is converted into a standard two-wire 4–20 mA output for connection to a PLC, alarm-monitoring system or tank-level display.
Main Features
- Continuous liquid-level measurement
- Two-wire 4–20 mA output
- Approximately 10 mm measurement resolution
- Weatherproof and explosion-proof versions
- SS316L, PVC and PTFE wetted-material options
- Standard and high-temperature configurations
- Optional local level display
- NAMUR NE43 fault-current support
- Custom measuring lengths
- Strong construction for marine and industrial tanks
- Suitable for corrosive and acidic liquids
Technical Specifications
| Specification | Typical details |
|---|---|
| Measurement principle | Magnetic float and reed-switch chain |
| Power supply | 24 VDC |
| Output | 4–20 mA, two-wire |
| Resolution | Approximately 10 mm |
| Measurement length | Approximately 250–5,000 mm |
| Stainless-steel pressure rating | Up to 20 kgf/cm² |
| Standard process temperature | Up to +80°C |
| High-temperature version | Up to +150°C |
| Ambient temperature | –20°C to +60°C |
| Standard enclosure | Weatherproof, IP65 |
| Explosion-proof option | Ex d IIC |
| Standard wetted material | SS316L |
| Alternative materials | PVC or SS316L with PTFE |
| Standard process connection | 100A JIS 10K flange |
| Cable entry | PF ¾-inch female |
| Optional display | Compact or remote display |
Main Variants
| Model | Description |
|---|---|
| HT-100RS | Standard stainless-steel version |
| HT-100RSH | High-temperature stainless-steel version |
| HT-100RS-Ex | Explosion-proof stainless-steel version |
| HT-100RSH-Ex | High-temperature explosion-proof version |
| HT-100RV | PVC version for corrosive liquids |
| HT-100RT | PTFE-lined version |
| HT-100RTH | High-temperature PTFE version |
Explosion-proof variants are available for applicable configurations.
Operating Principle
The float is manufactured according to the liquid’s specific gravity. As the tank level changes:
- The float travels along the guide tube.
- Its magnet sequentially activates internal reed switches.
- The resistance value changes according to float position.
- The internal converter changes the resistance into a proportional 4–20 mA signal.
- The signal is transmitted to the vessel’s PLC, display or monitoring system.
Typical Marine Applications
- Fuel-oil tanks
- Diesel-oil tanks
- Lubricating-oil tanks
- Freshwater and service-water tanks
- Cooling-water tanks
- Hydraulic reservoirs
- Chemical tanks
- Bilge and drain tanks
- Sewage-treatment tanks
- Industrial process vessels
Float Selection
Float size and material must be selected according to:
- Liquid density or specific gravity
- Process temperature
- Operating pressure
- Chemical compatibility
- Tank opening and nozzle diameter
- Required insertion length
A protection tube is recommended where the liquid is turbulent or enters the tank near the transmitter.
Optional Display
The HT-100R can be supplied with the HITROL M-100RD or remote display arrangement, providing:
- Level or distance indication
- Percentage or milliamp display
- Zero and span adjustment
- Approximately ±0.2% full-scale output accuracy
- NAMUR NE43 fault-current indication

