Introduction

A Head Mounted Temperature Transmitter, also known as a Hockey Puck Type Temperature Transmitter, is one of the most widely used transmitter designs in process industries. Compact, reliable, and cost-effective, these transmitters are installed directly inside the connection head of a temperature sensor such as a thermocouple or RTD.

They convert the small electrical signal generated by the temperature sensor into a standard and stable output signal — typically 4–20 mA or 0–10 VDC — which can then be transmitted over long distances to a controller, PLC, or monitoring system.

This makes head-mounted transmitters an ideal solution for accurate and interference-free temperature measurement in industrial environments.

Working Principle of Head Mounted Temperature Transmitters

The working principle is based on the conversion of low-level sensor signals into a linear output signal suitable for control or monitoring systems.

1. Sensor Input:
   The transmitter receives input from a temperature sensor such as a thermocouple (e.g., Type K, J, T, or E) or RTD (typically PT100).
2. Signal Conversion:
   • In a thermocouple, the small millivolt signal generated due to the temperature difference between hot and cold junctions is measured.
   • In an RTD, the transmitter detects changes in resistance caused by temperature variation.
3. Amplification and Linearization:
   The input signal is amplified, filtered for noise, and linearized to provide a proportional and standardized current or voltage output.
4. Output Transmission:
   The conditioned signal (usually 4–20 mA) is sent to a remote control system, ensuring accurate data transmission even across long cables.

Types of Inputs Supported

Head mounted transmitters are designed to accept different types of temperature sensor inputs:

• RTD Inputs: Commonly PT100 (3-wire or 4-wire configuration).
• Thermocouple Inputs: Types K, J, T, E, and others with built-in cold junction compensation.
• Thermistor or Millivolt Inputs: For specific or custom temperature ranges.

The flexibility of these inputs makes head-mounted transmitters suitable for a wide range of industrial applications.

Output Signals

The most common output format is the 4–20 mA analog signal, which offers:

• High immunity to electrical noise.
• Linear relationship between temperature and current output.
• No signal loss over long cable distances.

Other available outputs include 0–5 VDC, 0–10 VDC, and digital (HART or Modbus) signals, depending on the model.

Construction and Design Features

Head mounted transmitters are compact and ruggedly built to fit directly inside the connection head of the temperature probe.

Key design features include:

• Compact “Hockey Puck” Shape: Easily fits into DIN B or similar connection heads.
• Two Mounting Holes: For secure attachment to the sensor head.
• Durable Housing: Resistant to vibration, dust, and industrial conditions.
• Screw Terminals: Allow easy wiring and faster installation.
• LED or Calibration Option (in advanced models): For on-site verification.

2-Wire vs 4-Wire Configuration

• 2-Wire Transmitters:
  The same two wires are used for both power supply and signal transmission — making them simple, cost-effective, and widely used in most applications.
• 4-Wire Transmitters:
  Have separate pairs for power and signal, offering better signal stability and accuracy, especially for precision measurement.

Advantages of Head Mounted Temperature Transmitters

1. High Accuracy and Stability – Ensures precise temperature measurement over long distances.
2. Reduced Electrical Noise – The 4–20 mA output is highly resistant to interference.
3. Cost-Effective Wiring – Eliminates the need for expensive extension cables.
4. Compact and Space-Saving Design – Fits inside the probe head, minimizing external components.
5. Easy Maintenance and Calibration – Zero and span adjustments are accessible.
6. Compatible with Multiple Sensors – Supports both RTD and thermocouple types.

Typical Applications

Head mounted temperature transmitters are used across a variety of industries that require accurate and reliable temperature monitoring:

• Oil & Gas Industry – For process and pipeline temperature monitoring.
• Chemical & Petrochemical Plants – For reaction and distillation processes.
• Food & Beverage Industry – For sterilization, cooking, and packaging processes.
• Power Generation – In boilers, turbines, and exhaust systems.
• Pharmaceutical Industry – For controlled environment monitoring.
• Water & Wastewater Treatment Plants – For process control and automation.

Why Choose a Head Mounted Temperature Transmitter?

If your application requires compact installation, precise measurement, and reliable signal transmission, a head-mounted transmitter is the best choice. It provides an efficient interface between the temperature sensor and your control system while ensuring accuracy, stability, and cost savings.

Conclusion

A Head Mounted Temperature Transmitter plays a crucial role in modern industrial temperature measurement systems. By converting low-level signals into standardized output, it ensures accurate monitoring, smooth process control, and long-term reliability.

Whether used with RTDs or thermocouples, this compact device delivers high performance even in challenging environments, making it an essential component in today’s process automation systems.

At Doshi & Sons, we offer a wide range of Head Mounted Temperature Transmitters compatible with different sensor types and industrial standards.