Product Overview

The document details the FineTek PB series pressure-type liquid level transmitters, which utilize piezo-semiconductor bridge sensors with stainless steel diaphragms. Pressure applied to the diaphragm is transmitted via silicone oil to the semiconductor bridge, generating an unbalanced voltage signal. This signal is amplified and converted into a 4–20mA current output proportional to the liquid level.

The liquid level (H) is calculated using the formula P = θ × H, where P is pressure, θ is the liquid's pressure constant (pressure per meter of water column), and H is the liquid height.

Operating Principle and Types

• Types include insertion type, flange type, and guide rod type transmitters.
• They support long-distance signal transmission and can interface with meters, recorders, computers, PLCs, and alarms.
• The sensor diaphragm is stainless steel, suitable for viscous, weak acid/base, or impurity-containing liquids, such as reservoir water and wastewater treatment.
• Internal temperature compensation ensures long-term stability.
• Multiple flange and thread connection options are available, including food-grade connectors on request.

Product Variants and Applications

• Flange high-temperature type (EC1200) for high-temperature liquids.
• Cable insertion types (EC1310–1320) for deep water level measurement.
• Pressure transmitters (EC1500) for machinery pressure measurement and control (hydraulic, pneumatic, pump pressure control).
• Guide rod types (EC1100, EC1110) suitable for stirred or flowing liquids.

Technical Specifications

Installation and Wiring

• Guide rod and insertion type junction boxes should be installed with the cover facing upward; flange type junction boxes installed sideways with cable entry downward.
• Special vented cables must not be bent or crushed to maintain atmospheric communication.
• Recommended cable: 18AWG or 16AWG shielded isolation cable to reduce interference.
• Wiring diagrams provided for various models (EC1100, EC1110, EC1300, EC1310, EC1200, EC1210, EC1500).
• Power supply: 13–36 Vdc, output 4–20mA loop with max 500Ω resistance.
• If the digital display cannot supply 24 Vdc, an external DC power supply is required.
• Wiring should avoid proximity to power equipment to prevent electromagnetic interference.

Calibration and Adjustment

• Zero adjustment: set output current to 4mA when the tank is empty.
• Span adjustment: set output current to 20mA when the tank is full.
• Adjustment ranges: Span 18–24mA, Zero 3–5mA.
• Pre-calibrated at factory; unauthorized adjustments are discouraged.
• For non-standard 4–20mA output ranges, use PB series programmable meters.

Pressure Constant Conversion Table

The document includes a conversion table for pressure units (PSI, KPa, mbar, cmH2O, mmHg, kgf/cm²) to assist in calculations related to liquid level measurement.

Installation Guidelines and Limitations

• Do not apply external pressure or vacuum to the tank.
• Avoid dropping or striking the sensor to prevent damage.
• Do not clean the sensor diaphragm with high-pressure water jets.
• For corrosive organic solvents, use EC1200 model.
• Not suitable for liquids that crystallize or form clumps.
• For outdoor exposed installations (e.g., swimming pools), use protective covers (EC130E) for cable insertion types.
• Operating temperature generally up to 80°C except EC1200 (high temperature).

Ordering Information

Ordering codes specify model type, pressure range, connection type (flange, thread), material (SUS304, SUS316, PTFE), length increments (in 500mm steps), and special specifications. Tolerances on total length are ±5mm. Customers are advised to consult sales for detailed requirements or custom orders (OEM/ODM available).

Contact and Support

FineTek provides multiple regional offices and distributors in Taiwan, China, Singapore, Germany, and the USA with contact details for sales and technical support.