FOCIS System

Fiber Optic Clearance and Identification Sensor (FOCIS™), is a multi-function optical system providing industry leading performance for the measurement of:

  • Blade Tip Timing
  • Blade Vibration Monitoring
  • Blade Tip Clearance
  • Rotor Speed Measurement
  • Blade Crack Detection
  • Blade Twist
  • Blade Damage

The system can be configured to measure one or several of the components above.

 

System Architecture

The main elements of the system are:

Elements of the FOCIS System

Optical Probes

The optical probes are sensors which are installed on the rotor casing.  Prime Photonics manufactures the widest selection of probes available today, with many unparalleled advantages.

Sensor Interface Unit (SIU)

The Sensor Interface Unit (SIU) generates a laser beam which is transmitted through the optical probes.  The blade reflects the light back into the probe at each blade passage, generating a pulse.  The Sensor Interface Unit captures the waveform of the reflected light and converts it into an analog voltage.  

Data Capture Unit (DCU)

The voltage from the Sensor Interface Unit is transmitted to the Data Capture Unit which digitizes the waveform, acquires relevant data, and transforms the data into measured quantities such as time of arrival for blade tip timing, distance for blade tip clearance, or rotor speed of rotation.

 

Advantages At A Glance

Superior Performance

With 100 MHz sample rates on all channels simultaneously and best-in-class optical amplifier designs, FOCISTM Sensor Interface Units and Data Capture Units provide superior frequency response and low noise performance, resulting in the highest quality blade tip timing measurements available today.

High Temperature

FOCISTM offers the best quality probes available today.  A variety of our optical probes are qualified to 700 deg C (1300 F) without cooling.  Cooled probes are also available for operation in turbine environments at very high temperatures.

Multifunction

FOCISTM multi-function BTT/BTC probes can make both a timing and clearance measurement, allowing both measurements to be made with only one casing penetration and cable.

No Metal, No Problem

FOCISTM optical clearance sensors work with all types of blades regardless of material: metallic, ceramic, composite, plastic, and more.