DTS - Optical fiber distributed temperature sensing systems


Five roles of Optical Fiber Temperature Information Systems (DTS)
01:Monitor temperature
02:Detect temperature
03:Observe temperature
04:Measure temperature
05:Manage temperature

Optical Fiber Temperature Information System (DTS)

DTS - Optical fiber distributed temperature sensoring systems (DTS)

DTS is a system in which the optical fiber itself serves as the sensor, measuring the continuous thermal distribution along its length, so that it can monitor heat generation and detect fire over wide areas.
It can measure temperature distribution over a distance of up to 8km, at prices far lower than could be achieved by conventional methods.

Read a detailed explanation of the measurement principles employed by optical fiber distributed temperature sensing systems (DTS)

Read an explanation of the loop configuration we use with optical fiber distributed temperature sensing systems (DTS)

Features of optical fiber distributed temperature sensing systems (DTS)

Measurement principles
The measurement principle is based on the intrinsic temperature dependant nature of Raman scattering generated when a laser pulse launched into the optical fiber, propagates along the optical fiber.
The Raman scattering is split into two bands of Stokes and Anti-Stokes roughly symmetrical about the incident laser pulse wavelength.
Where the band of Anti-Stokes(shorter wavelrngths) exhibits a distinct temperature sensitivity and the band of Stokes(longer wavelength) is weakly temperature sensitive.
Monitoring the back scatter of Anti-Stokes and Stokes by using OTDR(Optical Time Domain Reflectmetory) technology allows distributed temperature sensing, since their intensities are dependent on the fiber temperature.
In practice, the ratio of Anti-Stokes to Stokes Light intensities is used for distributed temperature measurement to obtain the absolute temperature. Because the ratio is not affected by bend loss, splice loss, or connection loss.

Our unique loop configuration delivers the best performance under all measurement conditions
The measurement accuracy of the optical fiber DTS using Raman scattering is badly affected with the fiber attenuation fluctuation along the fiber length.
The attenuation might be changed in high temperature beyond 350 °C, or low temperature below -200°C, and also be discontinuous at splicing, connecting, and bending points.
However, the loop measurement configuration, in which the laser pulses are injected into the fiber cable alternately from both ends, can resolve these difficulties by automatic cancellation of the cable attenuation effect.

Automatic adaptation to a broken optical fiber
Even if the optical fiber in a loop configuration breaks, a fiber breakage alarm is output, and the system automatically switches to single-end measurement from both sides, so that it can continue measuring.

Built-in CPU
A built-in CPU processes temperature measurement, error judgment, self diagnosis and other functions, so no external PC is required for normal monitoring.
The system starts working when the power is turned on so recovery from a power interruption is very simple.

Zone setting function
The optical fiber can be divided into any desired length and, in the case of fire detection modules, assigned up to 800 different zone settings.
Individual alarms can be set for each zone and multiple settings can be superimposed.

Self-diagnostic function
Laser power and light sensor sensitivity are constantly monitored and an alarm is issued if their performance degrades below certain levels.


Monitor temperature

Detect temperature

Observe temperature

Measure temperature

Manage temperature
Page top

Copyright (C) 2007 NK Systems Limited