Cable Probes

Cable Probes

Cable probes are compact RTD and thermocouple thermometers built with a non-removable, flexible cable, allowing the sensing tip to be routed and positioned where rigid-stem instruments are difficult to install. They are available either without a process connection for plugging into existing provisions or with standard connections such as compression fittings and threaded process connections, plus specialty options such as weld-on pads or bayonet locks. The probe sheath is typically in direct contact with the process medium, supporting responsive measurement.

The flexible construction supports installations that require bending around obstructions or locating the sensing point in confined geometries. RTD variants are commonly selected when accuracy and long-term stability are the priority, while thermocouple variants extend the usable temperature range and handle high thermal gradients well. Cable routing also enables separation of the hot zone from the termination point, helping protect connectors and electronics.

Key benefits center on mechanical adaptability and reduced installation constraints. A small sensing mass and direct contact can improve response time for control and monitoring, and the cable provides strain relief compared with fully rigid assemblies when subjected to vibration or movement. This form factor often reduces engineering effort for retrofit measurement points and helps minimize the footprint on compact equipment and skids.

Specification typically focuses on sheath and cable materials for corrosion and temperature compatibility, the required immersion length, and the interface that best supports maintenance. Compression fittings allow adjustable insertion depth; threaded and weld-in styles suit fixed installations; bayonet connections facilitate quick change-out on serviceable machinery. Lead configuration, grounding, and cable length should be matched to the environment to preserve signal quality and service life.

Typical applications include machinery and equipment packages, HVAC systems, storage temperature monitoring, laboratory equipment, autoclaves, bearing temperature monitoring, and high-pressure or cryogenic services. Cable probes are also selected when space is limited or the measuring point requires a bent sensor path, and they can be used for surface temperature monitoring of reactors.

Miller Mechanical Specialties, an exclusive authorized representative of sales and service for Endress+Hauser.