Fiber Optic Temperature Sensor / Probe
Measures temperature at the defined physical point.
POINT FIBER OPTIC TEMPERATURE MEASUREMENT
Fiber Optic Temperature Measurement
Fiber optic temperature measurement uses an optical sensing probe and fiber connection to measure temperature at defined physical points without requiring an electrical sensing path at the measurement location.
INNO uses fluorescence lifetime point sensing for applications where high voltage, strong EMI, RF, microwave energy, magnetic fields or electrical isolation requirements make conventional electrical temperature sensors difficult to use.
INNO systems use point fiber optic temperature measurement rather than distributed temperature sensing (DTS).
MEASUREMENT OVERVIEW
What Is Fiber Optic Temperature Measurement?
Fiber optic temperature measurement is the use of an optical sensing element and optical fiber to determine temperature at a physical measurement location. In a point sensing system, each probe measures one defined location and transfers the optical response to a compatible monitoring instrument.
Unlike electrical resistance or thermoelectric sensors, the sensing path at the measurement point is electrically passive. This makes point fiber optic temperature measurement useful in high-voltage, high-EMI, RF, microwave and magnetically sensitive environments.
INNO uses fluorescence lifetime-based point temperature sensing. The detailed optical principle is explained on the technology page: fluorescence lifetime fiber optic temperature sensing.
MEASUREMENT PRINCIPLE
How Fiber Optic Temperature Measurement Works
- 01
Optical Excitation
The monitoring instrument sends light through the optical fiber toward the sensing tip.
- 02
Temperature-Sensitive Sensing Tip
The fluorescent sensing material at the probe tip responds to the optical excitation.
- 03
Fluorescence Decay Response
The returned fluorescence decay characteristics vary with temperature.
- 04
Optical Signal Processing
A compatible demodulator or monitoring instrument evaluates the optical response.
- 05
Temperature Output
The processed result is converted into a temperature value for display, alarm, recording or higher-level system integration.
This page explains the practical measurement chain. For the detailed physical principle, see: Fluorescence Fiber Optic Temperature Sensing Technology.
SYSTEM COMPONENTS
Fiber Optic Temperature Measurement System Components
Optical Fiber / Extension Cable
Carries excitation and return light between the sensing location and monitoring instrument.
Fiber Optic Temperature Transmitter / Demodulator
Processes the optical response and converts it into temperature data.
Local Display / Monitoring Host
Provides local temperature display, alarm or channel monitoring where required.
PLC / SCADA / Data Integration
Transfers measurement data to plant or supervisory systems through supported industrial interfaces.
TYPICAL SPECIFICATIONS
Typical Fiber Optic Temperature Measurement Specifications
| Parameter | Typical / Available Configuration |
|---|---|
| Measurement Principle | Fluorescence lifetime |
| Measurement Type | Point temperature measurement |
| Temperature Range | -40 to 250 / 260 °C depending on probe configuration |
| Accuracy | Depends on probe and monitoring-instrument configuration; see individual product specification |
| Resolution | 0.1 °C where supported |
| Response Time | Depends on probe configuration |
| Probe Diameter | Approx. 1.5–3 mm depending on model |
| Fiber Length | Fixed or configurable depending on probe |
| Number of Channels | Up to 64 depending on monitoring instrument |
| Communication | RS485 / Modbus where supported |
| Analog Output | 4–20 mA where supported |
| Electrical Characteristics | Passive, electrically isolated optical sensing path |
Listed values depend on the selected probe and monitoring instrument. Confirm the individual product specification before ordering.
APPLICATIONS
Where Fiber Optic Temperature Measurement Is Used
Transformer Windings
Direct point temperature measurement at selected winding and hot-spot locations.
View applicationSwitchgear & Busbars
Temperature measurement at busbar joints, contacts, cable terminations and selected electrical connection points.
View applicationMotors & Generators
Point measurement at selected stator winding and other critical thermal locations.
View applicationHigh-Voltage Testing
Electrically isolated temperature measurement on test objects and selected high-voltage measurement points.
View applicationMRI & RF
Non-conductive temperature measurement in strong magnetic-field and RF environments.
View applicationIndustrial Microwave
Point temperature measurement in microwave and other strong electromagnetic-field processes.
View applicationPower Electronics & Semiconductor
Localized thermal measurement for semiconductor, ESC, IGBT / SiC and electrically demanding test environments.
View applicationIndustrial Research & Test Equipment
Multi-point temperature measurement for test rigs, laboratories and specialized equipment.
View applicationMEASUREMENT SELECTION
How to Select a Fiber Optic Temperature Measurement Setup
- 01
Measurement Point
Define the exact physical location where temperature must be measured.
- 02
Temperature Range
Confirm the expected minimum, normal operating and maximum temperature.
Review temperature range guidance - 03
Probe Size and Installation Space
Confirm available space for the sensing tip, probe body, mounting arrangement and optical routing.
- 04
Fiber Route and Length
Measure the actual route from the sensing point to the monitoring instrument, including feedthroughs and installation allowance.
Plan probe length and structure - 05
Mechanical Protection
Determine whether polyimide, armored, protective-tube or application-specific probe construction is required.
- 06
Electrical / EMI Environment
Identify high voltage, RF, microwave, magnetic-field or isolation requirements.
Review high-voltage applications - 07
Number of Measurement Points
Count the independent physical points that must be measured at the same time.
Plan multi-point measurement - 08
Monitoring and Communication
Select the required channel count, local display, alarm, RS485 / Modbus, analog output or PLC / SCADA interface.
View monitoring instruments
POINT SENSING VS DISTRIBUTED SENSING
Point Fiber Optic Temperature Measurement vs DTS
| Feature | Point Fiber Optic Temperature Measurement | Distributed Temperature Sensing (DTS) |
|---|---|---|
| Measurement Method | Defined probe tip | Temperature along fiber length |
| Measurement Location | Specific physical points | Distributed fiber route |
| Sensor Structure | Individual point probes | Sensing fiber acts as distributed measurement path |
| Typical Use | Known critical hot spots and selected equipment locations | Long-distance distributed monitoring |
| Channel Logic | One active probe per measurement point | Distributed position along fiber |
| INNO Product Scope | INNO point fiber optic temperature sensors and monitoring systems | Not the product scope of this page |
INNO focuses on fluorescence lifetime point temperature measurement rather than DTS.
MEASUREMENT METHOD COMPARISON
Fiber Optic Temperature Measurement vs Conventional Electrical Sensors
| Feature | Fiber Optic | PT100 / RTD | Thermocouple |
|---|---|---|---|
| Electrical Conductivity at Measurement Point | Passive optical sensing path | Electrical sensor | Electrical sensor |
| EMI / RF Sensitivity | Optical sensing path, suitable for strong-EMI applications | Depends on installation and shielding | Depends on installation and shielding |
| High-Voltage Isolation | Suitable where electrical isolation is required | Requires appropriate insulation and installation | Requires appropriate insulation and installation |
| Measurement Type | Point | Point | Point |
| Signal Processing | Requires compatible optical monitoring instrument | Requires electrical measurement input | Requires thermocouple-compatible measurement input |
RELATED PRODUCTS
Related Products and Measurement Paths
MEASUREMENT QUESTIONS
Fiber Optic Temperature Measurement FAQs
What is fiber optic temperature measurement?
Fiber optic temperature measurement uses an optical sensing probe and optical fiber to determine temperature at a defined physical location. In INNO point sensing systems, each probe measures one specific point and sends the optical response to a compatible monitoring instrument.
How does fluorescence fiber optic temperature measurement work?
The monitoring instrument sends excitation light to a fluorescent sensing tip. The returned fluorescence decay response changes with temperature, and the compatible demodulator evaluates that response to calculate the temperature value.
How accurate is fiber optic temperature measurement?
Accuracy depends on the selected probe and monitoring instrument. Current INNO configurations include products with listed accuracy values from approximately ±0.3 °C to ±1 °C, depending on the application and product configuration. Confirm the individual product specification before selection.
Is fiber optic temperature measurement suitable for high-voltage environments?
Yes, point fiber optic temperature measurement is used where an electrically passive and isolated sensing path is required. The exact probe construction and installation must be selected according to the equipment and voltage environment.
Is fiber optic temperature measurement affected by EMI or RF?
The sensing path is optical rather than an electrical measurement circuit, which makes it suitable for many strong-EMI and RF environments. The complete system installation should still be designed for the actual application.
Is point fiber optic temperature measurement the same as DTS?
No. Point sensing measures temperature at defined probe tips, while distributed temperature sensing measures temperature along a fiber length. INNO products on this page use point sensing rather than DTS.
How many temperature points can one fiber optic system measure?
The number depends on the active channel capacity of the monitoring instrument. INNO offers single-point and multi-channel configurations, with current systems supporting up to 64 channels depending on the selected product.
Can fiber optic temperature measurement connect to PLC or SCADA?
Yes, when the selected monitoring instrument provides a compatible communication interface. Current INNO configurations include RS485 / Modbus options, with additional outputs available on selected products.
Discuss Your Fiber Optic Temperature Measurement Application
Send us the measurement point, expected temperature range, number of sensing locations, probe installation space, required fiber route and communication requirements.
- Measurement point
- Temperature range
- Probe size / installation space
- Fiber route and length
- Number of measurement points
- Required channels
- Display / alarm requirements
- RS485 / Modbus / PLC / SCADA requirements
Need Help with Fiber Optic Temperature Measurement?
Share your application and measurement requirements with INNO for probe, channel and monitoring-system selection.