Capacitive dew-point transmitter TDS501

NPT 1/2G 1/2Modbus

Overview
The TDS501 is an engineered dew point measurement system for industrial drying and compressed air applications. It provides continuous monitoring down to -70 °C Td using a four-element capacitive measuring method and robust sensor elements. The instrument is designed for stable 24/7 process control with fast response, high repeatability and an auto-calibration strategy that avoids signal freezing.

Application Areas

• Industrial drying: drying chambers for battery cells; drying ovens for coatings, powder coatings and electronics; plastics granulate and material drying
• Pharmaceutical industry: compressed air drying, coating quality control, filling and packaging processes
• Food & beverage: compressed air drying, quality control, filling and packaging processes

Key Features

• Dew point monitoring down to -70 °C Td (-94 °F Td)
• Continuous measurement without signal freezing
• Advanced auto-calibration for stable 24/7 process control
• Four-element capacitive sensor technology (E+E Quattro) with robust elements
• Fast response time and high repeatability
• Pressure rating up to 80 bar (1,160 psi)

Performance and Reliability
The TDS501 delivers repeatable dew point results under varying process conditions (temperature shifts, load changes, airlocks). Its integrated design—sensor element, electronics, mechanical housing and calibration algorithms—ensures reproducible measurement performance across devices and operating points, supporting stable control loops and reducing energy use and unplanned downtime.

Condensation Handling & Protection Concepts
Designed to remain reliable during short-term condensation or abnormal conditions, the TDS501 uses wettable sensing elements, a stainless steel sintered filter and a stainless steel housing to minimise condensation-related drift. Auto-calibration maintains long-term stability while keeping the output signal active.

Filter Options & Response Time
Standard configuration includes a stainless steel sintered filter to balance protection and response time in industrial environments. An optional open filter cap is available for applications (e.g. cleanrooms) requiring faster response and earlier detection of dew point changes.

Integration & Outputs
The TDS501 offers analogue and digital interfaces for straightforward integration into process control systems. Typical outputs and options include Modbus RTU (RS485), 4–20 mA current output with wide scaling and an industrial M12x1 connector for flexible connection to control and monitoring equipment.

Technical specifications

• Model: TDS501
• Dew point measuring range: -70...+60 °C Td (-94...+140 °F) (capability down to -70 °C Td)
• Accuracy: ±2 °C Td (±3.6 °F)
• Pressure rating: 80 bar (1,160 psi)
• Digital interface: RS485 (Modbus RTU)
• Analogue output: 4–20 mA (wide scaling) (optional)
• Protection rating / Enclosure: IP65
• Sensor technology: E+E Quattro four-element capacitive sensor with auto-calibration
• Construction: stainless steel housing; stainless steel sintered filter (standard); optional open filter cap
• Process connections: stainless steel; G 1/2" ISO or 1/2" NPT (typical options)
• Features: temporarily wettable sensing elements; configurable filter caps; industrial M12x1 connector for outputs