The intrinsic temperature measuring system DTS based on LIOS Technology’s design, with fibre optic sensors either installed within the power cable’s cross section (FIMT – Fibre in metal tube ) or attached to the exterior of the cable, makes it possible to record the temperature profile along an entire cable route continuously, and to pinpoint the exact location of hot spots within a metre.
Most commonly the measured temperature profile data is transmitted via standard interfaces from systems of the DTS as required, and be either displayed or further processed by PC, PLC or SCADA systems. As a result of the increasing demands placed on the ability to network and integrate measuring systems into management systems, LIOS offers network components that summarise DTS data from several DTS units and transport or convert it to the required network standards and protocols like Modbus, DNP3, IEC60870-5 or XML based data interfaces (e.g. POSC).
Equipped with the Embedded Communication Module (ECM) the Distributed Temperature Sensing (DTS) evaluation unit is accessible by Ethernet/ LAN, holds its own IP address and is compatible with DHCP.
The on-board storage facility of measurement data provides automatic buffering of network break downs. It can handle multiple protocols, so the DTS can be directly linked to PLC or SCADA systems and communicates in various industrial protocol standards providing measured data and customised alarm information.
Hereby, the evaluation unit communicates as a TCP /IP server with several clients.
Features of the embedded communication module of the LIOS DTS controller:
- Configuration and operation of the DTS via two independent channels:
- Ethernet TCP/IP
- Onboard storage of measurement data
- Buffers up to 72 hours of measurement data and initiates data transfer automatically after communication link was re-established
- Individual file access to measurement data through CHARON_02 (onboard data storage 1 GB)
- Allows to operate individual Plug-In-Interfaces for customer specific protocol solutions
- The DTS can communicate in parallel with its proprietary protocol and one or more customer specific protocols like DNP3, IEC60870-5-104, IEC61850, POSC WITSML, Modbus (Master/Slave) etc.
- Individual assignments for protocols and client addresses (IP) possible
- Ethernet communication to and from clients with high bandwidth
- Module comes with built-in user configurable Firewall and enables reliable operation even in WAN’s
- Secure data transmission and individual authorisation according TLS- Standard (RFC 2246)
The most common industrial protocols used in electrical systems worldwide are introduced in the following section. However, also other protocol standards are available or can be implemented for the ECM. Please contact us in case of questions.
The MODBUS protocol was published by Modicon in 1979. It is a quite simple single master – multiple slave protocol widely used in general purpose SCADA applications. It provides binary (bit) and 16-bit integer data, but no floating point values, polled by the master, i.e. the slave cannot send data spontaneously. The protocol specification is openly published and royalty-free. In the DTS ECM, TCP/IP is used as transport layer.
IEC 60870-5 provides a communication profile for sending basic Telecontrol messages between systems. It was developed by the IEC Technical Committee 57 (Working Group 03) as a protocol standard for Telecontrol, Teleprotection, and associated telecommunications for electric power systems. The result of this work is IEC 60870-5. The protocol provides inter alia bit, integer and floating point data with or without time stamps. Data is transmitted from controlled stations (slaves) either by polling or spontaneously. In the ECM the IEC 60870-5-104 companion standard, defining standard TCP/IP connections as transport layer, is used.
DNP3 (Distributed Networking Protocol) is an open standard managed by the DNP User Group. Initially; the DNP3 protocol was developed by Westronic (now GE-Harris) in 1993. It is widely used in electrical systems worldwide, including North and South America, the UK, Southeast Asia, South Africa, Australia, and New Zealand. It has gained wider use beyond electrical utilities, e.g. for water supply as well. The DNP3 protocol is also referenced in IEEE Std. 1379-2000, which recommends a set of best practices for implementing modern SCADA Master-RTU/IED communication links.
The protocol provides bit, integer and floating point data and time stamps. Data is transmitted from the outstation (slave) either by polling or spontaneously. The ECM uses TCP/IP as transport layer, but even in this mode the DNP3 protocol additionally uses its own protocol stack for synchronisation and error checking. This provides extra security.
IEEE Lays Groundwork for Adoption of DNP3 Protocol as New IEEE Standard
IEEE, the world’s leading professional association for the advancement of technology announced that work is underway for the formal recognition of Distributed Network Protocol (DNP3) as an IEEE standard. Designated as IEEE P1815, the standard will promote interoperability across hundreds of operational systems with thousands of installed devices, as well as strengthening security protocols while maintaining compatibility with existing object models.
Seen at EnergyCentral’ T&D News 19 January 2010