M12 and M8 circular connectors provide a safe and reliable connection for temperature sensors and have revolutionized the world of industrial automation and connectivity. Various sensors utilize these types of connectors which have become the industry standard in various industrial applications. The corded connectors used to connect the sensor to a control device are readily available. This type of connection offers a tight seal that is an ideal choice for washdown and corrosive environments.

A customer in the Plastics Industry requested that Tempco incorporate M12 connectors into various Resistance Temperature Detector (RTD) sensors such as probe assemblies and melt bolt assemblies.

The connectors for these particular assemblies have 4 pins for a 4-wire RTD circuit. A typical wiring scheme is shown in Figure 1 (other wiring schemes, such as 2-wire and 3-wire, can also be manufactured). Other design features include:

• Standard assemblies are rated 200º C, and up to 450º C as an option.
  The connector is rated 85º C Max.
• Probe assemblies can be manufactured in 1/4”, 3/16” and 1/8” diameters.
  Metric sizes are also available upon request.
• 1/4” and 1/2” NPT threads are typical for process connections.
• Melt bolt assembles are typically made with 1/2-20UNF thread.
• RTD sensors are available in class “A” and “B”.