The Siemens Industry Automation Division is adding telecontrol functions to the latest version of its Simatic PCS 7 process control system.
Simatic PCS 7 Telecontrol connects distant substations to the central control system by means of telecontrol. In terms of the operating philosophy and alarm signalling, there is no difference between the local or distant station as far as the plant operator is concerned. Several different media are available for communication, such as dedicated lines, dial-up connections or radio systems.
Simatic PCS 7 Telecontrol integrates distributed, distant substations and a central control system to form a homogeneous overall system. This enables applications to be created that are integrated with regard to operation and alarm signalling; in addition, the risk of operating errors is reduced, and the engineering and servicing costs are also lowered. In large-scale plants, a redundant configuration increases plant availability, with redundant servers comparing their process values, curves and alarm statuses with each other.
Communication with the external substations is performed over dedicated lines, dial-up lines or radio systems and, in new plants, increasingly with TCP/IP-based techniques, with either DSL or GPRS. Simatic PCS 7 Telecontrol supports the Sinaut ST7 and Modbus protocols over serial as well as over TCP/IP-supported communication links. Further processing and archiving of the raw data, complete with time stamps received from the distant substations, are performed in the central PCS 7 Telecontrol server. Simatic PCS 7 Telecontrol function blocks are provided for this purpose for the Simatic PCS 7 standard control system. The user interface and error message hierarchy as well as the symbols and faceplates correspond to those of Simatic PCS 7 and present users with the familiar system environment.
The Sinaut ST7 telecontrol protocol is designed to be robust and can also be implemented for slow or sensitive transmission paths. For example, data is buffered in the distant substations to bridge faults or sporadic connection interruptions in radio networks without losing important data.
The wide-ranging applications of Simatic PCS 7 Telecontrol extend from the oil and gas industry - for example, for compressors, pressure reduction, transfer and metering stations in gas supply networks as well as for pumps and valve stations in oil pipelines - through to the water supply and treatment sector. In the latter, the system provides telecontrol for sprinkler, pump and valve stations in water supply networks as well as for rainwater overflow basins and hoisting plants in waste water systems.
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