Expert interview: The use of Raman distributed temperature sensing in industrial plants for hotspot monitoring

Yokogawa employee Ralf Cymontkowski interviewed Toru Fukuzawa and Etienne Friedrich about the use of Raman Distributed Temperature Sensing in industrial plants for hotspot monitoring.

Yokogawa employee Ralf Cymontkowski interviewed Toru Fukuzawa and Etienne Friedrich about the use of Raman Distributed Temperature Sensing in industrial plants for hotspot monitoring.

Mister Fukuzawa, as the Head of DTSX Solution Planning Section from our headquarter, could you please tell about background of DTSX product development?

Toru Fukuzawa: Yokogawa starts in the 90th to cooperate with the well-known fiber optic sensing company ANDO and acquire in 2002 the 100% of the stock. In 2011 we release the DTSX200, a complete inhouse development with special sampling resolution of 10cm.

What is the benefit of using this special sampling resolution for the Yokogawa clients?

Fukuzawa: By using integrated optical fibers in plant assets with DTSX200, our clients are able to detect unnormal temperatures at precise conditions.

Why is this so important and for which applications is it typically used for?

Fukuzawa: Industrial assets are expensive and downtime would increase operational costs for our clients. Typically distributed temperature sensing is used in monitoring high voltage power cables, pipeline leak detection, downhole monitoring, furnace monitoring or for fire detection, which is the largest market.

The DTSX product line is part of the OpreX strategy. Could you please briefly explain what is OpreX?

Fukuzawa: The OpreX brand name stands for excellence in the technology and solutions that Yokogawa cultivates through the co-creation of value with its customers, and encompasses the entire range of Yokogawa’s IA products, services, and solutions.

Dear Mister Friedrich, as specialized company for fiber optical sensing cables and as the product manager for temperature sensing cables, what is your experience about the use cases of Raman Distributed Temperature Sensing (DTS)?

Friedrich: Raman DTS is a well-proven solution for the temperature monitoring of long assets. Examples of applications include the monitoring of high voltage power cables, fire detection systems in tunnels, pipeline leak detection, downhole process controls, environment monitoring of water flows, and many others. Purpose-designed fiber-optic cables maximize the performance of the DTS system and are tailored for the respective application environments.

What makes the Raman DTS so attractive for industrial process monitoring?

Friedrich: The fully passive and rugged nature of the fiber-optic DTS cables makes the solution attractive to a wider range of applications. The Raman DTS solution is consequently preferentially selected also for projects with shorter asset lengths. The monitoring of industrial processes is a case in point. Process efficiency and operating cost are closely related, and industrial assets are intrinsically expensive. Down-times are costly, and failures are not an option. Efficient and reliable process monitoring is therefore essential.

What was the intension to test the Raman DTS unit with your cable?

Friedrich: To understand the specific behavior of the DTSX200 in case of hotspot monitoring, because of this criticality, industrial asset managers demand proven solutions. Practically, they request data from previous projects or extensive test reports. Sometimes our clients asking us for our independent opinion, which DTS measuring unit could be used for specific project requirements.

Based on which parameter do you offer your sensing cable for industrial process monitoring?

Friedrich: Industrial process are extremely diverse, with each their specific chemical and temperature conditions. The DTS sensing cable will be selected based on the corrosiveness and temperature of the environment. And the ability of the system to detect critical temperature changes is essential. Indeed the reliability of the system, its response time, and the avoidance of false alarms are essential, whereas the measurement of exact temperatures is less so.

Regarding the hotspot monitoring test, could you please explain how you proceed the test.

Friedrich: We tested our temperature sensing cable BRUsens DFOS DTS 4MMF 3.8mm. The length was 13m with four inner fiber which were looped back, so total measurement distance was 52m (~60m incl. pigtails). As hot spots we used 2.3cm Aluminum disks with a temperature of 85°C and Aluminum foil for improved heat uniformity around the cable. So these hotspots were detected four times per disk along the measurement distance. Yokogawa provided for this test their DTSX200 measuring device. The system operates with a spatial resolution of 1m and selectable sampling resolution of 10, 20, 50 or 100cm. The test were performed in e single-ended setup.

What were the main intensions and could you please explain briefly the test procedure.

Friedrich: We wanted to know if the hot spots be distinguished, the repeatability and the acquisition speed. Therefore we varied distances between two hot spots, measuring time and sampling resolution.

For us as the Raman DTS supplier, we are appreciate your effort in evaluate your sensing cable with our measuring unit. Could you please summaries your output from the test.

Friedrich: After the evaluation of all measurement results, we are now understand the performance of the DTSX200 with our sensing cable. The Yokogawa Raman DTS can detect small hot spots of 2.3 cm effectively. Therefore we believe Yokogawa provide an attractive DTS unit for new monitoring solutions in extreme industrial application conditions.

Thank you very much for this feedback and your effort. Mister Fukuzawa, I would like to give you the last word.

Fukuzawa: We appreciate the effort from SOLIFOS to test our DTSX200 hotspot function and we are always very please to get feedback from our suppliers, partners and clients. Our vision statement is “Process Co-Innovation”, which means we are creating new value with our clients for a brighter future. Thank you very much.


YOKOGAWA is a leading provider of Industrial Automation and Test and Measurement solutions. Combining superior technology with engineering services, project management, and maintenance, Yokogawa delivers field proven operational efficiency, safety, quality, and reliability.


SOLIFOS delivers specialized fiber optic cables and solutions for diverse applications. Designed for operation in harsh environments, our high-tech cables and systems fulfill their intended function. Whether you consider permanent or temporary installations, data transmission or distributed fiber optic sensing: you can rely on SOLIFOS.

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