Non-Contact Proximity Probes

Machine Saver probes are at the forefront of eddy current proximity probe design, are well acknowledged in the industry, and are compatible with all significant transducer producers. The American Petroleum Institute Standard 670 is completely complied with by the MS-Series probes (API-670). We guarantee the viability and durability of these proximity probes and associated systems for up to ten years, with a default warranty of three years that is extendable to five years at the customer's request. We are the only known American manufacturer of mass-produced vibration probes. In order to support a preventative maintenance program and machinery diagnostics, today's high-performance eddy current proximity sensors provide continuous condition monitoring information and trip monitored machines when necessary. Our leading proximity solutions provide full interoperability and exceptional performance in challenging environments.

Non-Contact Proximity Probe System

An industrial non-contact proximity probe typically consists of a coil, a mandrel, and a cable. Here's how these components are combined to make the probe:

  1. Coil: The coil is typically made of a fine wire wound around a former, which is usually made of a non-conductive material. The coil is a critical component of the probe, as it generates the electromagnetic field that interacts with the target object.

  2. Mandrel: The mandrel is a tubular structure that is typically made of a non-magnetic material, such as stainless steel or titanium. The coil is wound around the mandrel, which helps to keep it in place and maintain its shape.

  3. Cable: The cable is used to connect the probe to the driver and signal conditioning electronics, which are typically located outside the sensing environment. The cable is typically made of a shielded coaxial cable that is designed to minimize noise and interference.

To assemble the probe, the coil is wound around the mandrel, which is then typically coated with a layer of insulating material to protect the coil from the environment. The cable is then attached to the coil, and the entire assembly is typically mounted on a support structure, such as a bracket or flange.

When the probe is in operation, the electromagnetic field generated by the coil interacts with the target object, which induces eddy currents in the object. These eddy currents generate a secondary electromagnetic field that is detected by the coil, and the resulting signal is then transmitted through the cable to the driver and signal conditioning electronics for processing and analysis.

An industrial non-contact proximity probe typically consists of the following components:

  1. Sensor Head: This is the part of the probe that detects changes in position and proximity of the target. It typically uses electromagnetic or capacitive sensing technology.

  2. Signal Processing Unit: This unit is responsible for processing the sensor signals and converting them into electrical signals that can be read by a monitoring system or control unit.

  3. Amplifier: The amplifier boosts the signal from the sensor head to improve its accuracy and reliability.

  4. Cable: This connects the sensor head to the signal processing unit and can be shielded to reduce electromagnetic interference.

  5. Mounting Hardware: This allows the probe to be securely attached to the machine or equipment being monitored.

  6. Power Supply: The probe requires a power source, which can be supplied by batteries or an external power supply.

  7. Output Display: This component displays the output of the probe, which can include the distance or position of the target.

3309 (Focus View) Series

3309 (Focus View) Series

3309 (Focus View) Specifications and Dimensions




Linear Range

2.0 mm (80 mils). Linear range begins at 0.38 mm (15 mils) from target and is from 0.38 to 2.41mm (15 to 95 mils).

Incremental Scale Factor (ISF)


7.87 V/mm (200 mV/mil) +12.5%/–20% including interchangeability error when measured in increments of 0.25 mm (10 mils) over the 1.5 mm (60 mils) linear range

Deviation from best fit straight line (DSL)

Less than ±0.06 mm (± 2.3 mils)

Frequency response

0 to 10kHz (-3 dB) typical, with up to 100 meters (300 feet) of field wiring.

Target Size

Minimum: 8.9 mm (0.35 in) diameter Recommended minimum: 13mm (0.5 in) diameter

Axial position measurements on shaft diameters smaller than 13mm (0.5 in) will generally result in a change in scale factor. Reducing the gap between the probe and target will help limit the change in scale factor.

Shaft Diameter

Minimum (standard X-Y probe configuration): 30 mm (1.2 in)

Minimum (X-Y proximity probes offset axially by 23 mm (0.9 in)): 20 mm (0.8 in)

Measurements on shaft diameters smaller than 30 mm (1.2 in) usually require close spacing of radial vibration or axial position transducers. This creates the potential for their electromagnetic emitted fields to interact with one another (cross-talk), resulting in erroneous readings. To prevent cross-talk, maintain minimum separation of m transducer tips of at least 25 mm (1.0 in) for axial position measurements or 23 mm (0.9 in) for radial vibration measurements

Probe Tip Material

Polyphenylene sulfide (PPS).

Probe Cable Specifications

75 Ω coaxial, fluoroethylene propylene (FEP) insulated probe cable in the following total probe lengths: 0.5, 1, 5, or 7 meters.

Extension Cable Material

75 Ω coaxial, fluoroethylene propylene (FEP) insulated.

System Length

5 or 7 meters including extension cable

Extension Cable Armor (optional)

Flexible AISI 302 SST with/without FEP outer jacket

Tensile Strength (maximum rated)

220 N (50 lb) probe case to probe lead. 220 N (50 lb) at probe lead to extension cable connectors. 220 N (50 lb) probe case to stainless steel armor

Connector material

Gold-plated brass

Recommended Connector Torque

Hand tightened

Maximum torque

0.56 N• m (5 in• lb)

Minimum bend Radius (with or without SS armor)

25.4 mm (1.0 in)

Probe Temperature Range Operating Temperature

-34°C to +177°C (-30°F to +351°F)

Storage Temperature

-51°C to +177°C (-60°F to +351°F)

Extension Cable Operating and Storage Temperature

-51°C to +177°C (-60°F to +351°F)

Relative Humidity

100% condensing, non-submersible when connectors are protected