HM – Head Mounted Transmitter

Overview
The Head Mounted Transmitter (HMT) is a compact, smart signal conditioning device designed to be installed directly into the connection head of a Temperature sensor. It is primarily used to convert RTD (Resistance Temperature Detector), Thermocouple (TC), resistance, or millivolt (mV) signals into a standard two-wire 4–20 mA analog output. This conversion allows reliable, noise-immune signal transmission over long distances, making the HMT an essential component in modern industrial Temperature measurement systems.

Working Principle
The transmitter receives a low-level signal from a Temperature sensor (RTD or thermocouple), amplifies and linearizes the signal, and then converts it into a stable 4–20 mA current signal. This signal can then be transmitted to a control room, PLC, or DCS for monitoring and control. The built-in cold junction compensation ensures accurate thermocouple readings, while PC-based configuration allows flexible setup and customization.

Key Features

• Signal Conversion: Converts RTD, Thermocouple, resistance, or voltage inputs to 4–20 mA analog output

• High Accuracy: ±0.1% Full Scale (FS) for precise measurement and control

• Input Types Supported:

  • 2 types of RTD input

  • 8 types of Thermocouples (e.g., J, K, T, E, N, R, S, B)

• Cold Junction Compensation: Built-in for accurate thermocouple performance

• Smart Configuration: Setup and parameterization via PC software

• Linear Measurement Options: Supports Temperature-linearity, resistance-linearity, and voltage-linearity

• Alarm Functionality:

  • Outputs 3.9 mA or 22 mA in case of sensor failure or open circuit

  • Optional KH213 smart model for enhanced diagnostics

• Saturation Current Range: 3.9 mA (low), 20.5 mA (high)

• Temperature Range:

  • Operating: -40°C to +85°C

  • Storage: -40°C to +100°C

• Compact Design: Easily fits into standard DIN connection heads (e.g., Form B)

Applications

• Industrial Temperature Control
• Power Plants and Utilities
• Oil & Gas Refineries
• Chemical & Petrochemical Plants
• Pharmaceutical Manufacturing
• Food & Beverage Processing
• HVAC & Building Automation
• OEM Equipment Integration