Overview
Telecontrol system with SINAUT ST7, IEC 60870-5 or DNP3
Telecontrol systems for extensive, advanced applications in the process industry are based on standardized protocols such as IEC 60850 and DNP3 (IEEE 1815) or special telecontrol protocols such as the proven Siemens protocol, SINAUT ST7. Our telecontrol system offers fully automatic monitoring and control of telecontrol stations based on SIMATIC S7 or compact SIMATIC RTU3000C telecontrol units, which exchange data with each other and with one or more control centers via a wide variety of communication networks.
It facilitates an integrated communications concept (TIA) and complete integration into the SIMATIC environment. The modular design and the support of a huge variety of network forms and operating modes including Ethernet permit the design of flexible network structures that can also contain redundant links.
The networks can be optimally adapted to the respective local conditions using all transmission media (mainly IP-based networks, e.g. DSL, mobile wireless, as well as conventional networks such as dedicated line, radio, dial-up networks, mobile wireless).
Benefits
- All IP-based and conventional WAN media can be combined as required, including path redundancy.
- Event-controlled data transmission including time stamping
- Local data storage
- Remote programming and diagnostics
- Integrated operator control and monitoring concept for WinCC/PCS 7 or connection to non-Siemens systems via OPC
Application
The telecontrol components have proven themselves in the smallest plants with only a few process stations, but also in complex networks with many hundreds of stations.
Examples of the range of uses:
- Safe supply of drinking water, gas or district heating for private and industrial consumers via branched networks
- Economical transportation of gas, oil or oil products through pipelines
- Reliable recording and transmission of process data from environmental monitoring systems
- Remote monitoring of wastewater systems
- Control of beacons, unit-type district heating power stations, conveyor systems or transportation systems
Design
The telecontrol system is based on the SIMATIC systems S7-1500, ET 200SP, S7-1200, S7-300, S7-400, the RTU3000C family and WinCC/PCS 7. It adds telecontrol functions to these systems using the hardware and software components listed below.
Hardware components
- Communications processors (CPs) for S7-1200 and ET 200SP
- Communications modules (TIMs) for S7-1500, S7-400 and S7-300
- Industrial modems and routers (SCALANCE M)
- Accessories such as modems, antennas and connecting cables
Software components
Software for configuration
- STEP 7 Professional (TIA Portal) is used for configuration of the telecontrol components.
- The SINAUT engineering software is still available for existing plants with STEP 7 V5.
Software for the central control center
- SINAUT ST7cc;
the SINAUT add-on for WinCC V7 - WinCC TeleControl;
add-on for SIMATIC WinCC for telecontrol applications - PCS 7 TeleControl;
add-on for SIMATIC PCS 7 V7 for telecontrol applications - SINAUT ST7sc;
software for interfacing ST7 with control centers that can operate as OPC clients
Function
Network configurations and operating modes
The telecontrol components support the set-up of complete hierarchical communication networks comprising stations, node stations and control center.
IP-based WAN such as DSL/Internet, GPRS, UMTS, LTE, 5G, etc. as well as conventional WAN networks such as dedicated line, radio and dial-up networks can be used for the exchange of information between the individual devices.
There are no restrictions on the combination of WAN types in a project. Point-to-point, line and node network topologies can be set up. Hybrid configurations of these basic structures are also possible.
A station can be linked using two transmission paths to permit redundant data transmission. The two paths can be of the same type or different, e.g. two Ethernet connections or dedicated line plus Ethernet.
The following network topologies are possible in the WAN:
- "Point-to-point"
- "Line"
- "Star"
- "Tree"
- "Ring"
The graphics below show examples of different network topologies that can be implemented with the components listed above.
Wide range of transmission networks for connecting substations (RTUs) to the control center
Redundant connection to a TeleControl control center (path redundancy) using the example of a telecontrol station based on S7-1500 with TIM 1531 IRC
The control center
The control center consists of a PC with SCADA software with telecontrol connection for the corresponding protocols and, if necessary, additionally a master PLC of the SIMATIC S7-1500/400/300 type.
A number of different versions can be selected as components of the central control center:
SINAUT ST7cc
the PC control center based on WinCC V7
This is the ideal control center system for SINAUT ST7. It has been designed specifically for event-driven and time-stamped data transmission on the SINAUT system and can be set up as a non-redundant or redundant system (to supplement the WinCC/PCS 7 redundancy package).
PCS 7 with PCS 7 TeleControl
This is the ideal control center system for plants in which larger local automation tasks have to be combined with telecontrol connections. In addition to SINAUT ST7, remote stations with other communication protocols can be connected, e.g. over DNP3 or IEC -60870-5-101/-104.
WinCC TeleControl
control center system for plants with the WinCC V7 HMI software, expanded with telecontrol connections. WinCC TeleControl offers the connection of SIMATIC substations communicating via IEC 60870, DNP3 or SINAUT ST7.
SINAUT ST7sc
OPC server for interfacing control centers from other vendors via the OPC client function;
the SINAUT telecontrol technology can also be connected to control center systems from other vendors via the "Data Access Interface". ST7sc features extensive buffer mechanisms which prevent data from being lost even if the OPC client fails. It can be connected to non-redundant or redundant clients.
SINAUT ST7cc control center system with connected substations (RTU)
IP-based networks
Telecontrol communication is performed via IP-based networks:
- Via public networks and the Internet using DSL or GPRS/UMTS/LTE/5G
- Wirelessly, by using special wireless systems optimized for Ethernet, e.g. the components of the SCALANCE W IWLAN system
- Distances of up to 120 km can then be covered via fiber-optic cables, e.g. by using SCALANCE X switches with optical ports
- Copper dedicated lines, private or leased
Conventional networks
The following conventional WANs can be used for data transmission:
- Copper dedicated lines, private or leased
- Private wireless networks (optionally with time slot procedure)/TETRA
- Dial-up networks (e.g. analog)
Change-driven data transmission
In the stations, the telecontrol software ensures that process data is transmitted between CPU and control center and from CPU to CPU in the event of changes. Connection, CPU or control center failures are displayed. A data update for all participating communication partners is performed automatically following debugging or startup of a CPU or of the control center.
Time-of-day always up to date
To enable subsequent and correct archiving of process data in the control center system, all data frames are already assigned a time stamp at their place of origin. The entire network is synchronized automatically – including daylight saving time changeover.
Local data storage
A special property of communications modules used in telecontrol plants is the capability for saving data which must be secured against loss in the event of failure of a connection or partner.
Since the telecontrol modules save data and transmit it at a later point in time with a time stamp, a suitable control center system must be used. It must also be possible to continue to process this data, specifically as regards subsequent archiving, if the data is received in the control center delayed by a number of hours or even days. Archive compressions such as the creation of mean, hourly and daily values also cannot be performed until all data for the relevant period has been received.
Remote programming and diagnostics
In industries in which telecontrol systems are used, the stations are distributed across wide areas and are often situated in locations that are difficult to access. Faults which require a visit to be made to a station of this type are associated with long journeys. A telecontrol system offers the optimal solution for this: Remote programming and diagnostics via the telecontrol network. All diagnostics and programming functions provided by SIMATIC RTUs for station automation and WAN communication can be used via the telecontrol path - without interrupting process data transmission.
Alarms as text messages
In order to alert standby service personnel, event-driven text messages can be sent to cell phones from the process stations. An acknowledgment that a message of this type has been received can be sent back to the sender CPU from the cell phone.
Integration
Protocols
IEC protocol 60870
IEC 60870-5-101, -104 are standardized, vendor-independent telecontrol protocols. They enable remote communication via both conventional and IP-based WANs. The following modules are offered for implementation of an RTU with IEC 60870 based on SIMATIC: CP 1243-1, CP 1243-8 IRC, CP 1243-7 LTE, CP 1542SP-1 IRC, TIM 1531 IRC as well as the compact RTU3000C module.
Possible operating mode in the IP-based WAN:
- Spontaneous mode / event-driven
DNP3 protocol
The DNP3 protocol (Distributed Network Protocol) is a standardized, manufacturer-independent telecontrol protocol. It enables remote communication via both conventional and IP-based WANs. The following modules are offered for implementation of an RTU with DNP3 based on the SIMATIC:
CP 1243-1, CP 1243-8 IRC, CP 1243-7 LTE, CP 1542SP-1 IRC, TIM 1531 IRC, TIM 3V-IE DNP3 and TIM 4R-IE DNP3 as well as compact module RTU3000C.
Possible operating mode in the IP-based WAN:
- Spontaneous mode / event-driven
Possible operating modes in the conventional WAN:
SINAUT ST7 protocol
SINAUT ST7 enables SINAUT communication via both conventional and IP-based WANs. The following modules are offered for implementation of an RTU with SINAUT ST7 based on the SIMATIC:
CP 1243-8 IRC, CP 1542SP-1 IRC, TIM 1531 IRC, TIM 3V-IE, TIM 3V-IE Advanced and TIM 4R-IE as well as compact module RTU3000C.
Possible operating mode in the IP-based WAN:
- Spontaneous mode / event-driven
Possible operating modes in the conventional WAN:
- Polling
- Polling with time slot procedure
Operating modes
- Spontaneous operation in the IP-based WAN
For transmission via an IP-based network, a permanent TCP connection is established in each case between two RTUs or between one RTU and the control center. Both partners exchange protocol-specific data packets over it using the TCP/IP transport protocol. Spontaneous mode here means that the data is usually sent to the communication partner immediately and without a request (polling). However, the spontaneous data can also be sent with a delay in order to achieve optimum and efficient data transmission. This may be important if networks subject to fees are used and the transferred data volume plays a role.
Networks without volume tariff:
When data is transmitted, it is transferred immediately to the respective partner regardless of any priority. Data is transferred in accordance with the FIFO principle. This does not apply to frames with "interrupt" priority. These are sent before any other frames that may still be in the buffer.
Networks with volume tariff:
In an IP-based network, such as the mobile network, the priority of the individual data frames (normal, high or interrupt) is taken into account. Data with normal priority is collected and transmitted in larger blocks, as soon as a specific size of block is achieved or when the specified TCP/IP keep-alive interval has expired. This saves transmission volume because a reduced frame overhead and fewer acknowledgment frames are required. Important data with high or interrupt priority is transmitted immediately. Normal frames that are buffered at this point are sent at the same time. Frames with normal or high priority are transmitted in accordance with the FIFO principle. - In polling mode, data exchange is controlled from the control center. It calls the connected stations (including node stations) in sequence. Terminals with modified data send this data as soon as they are called. Terminals with no modified data at the present time simply acknowledge the call. Data from the control center to the stations can be transferred at any time between the individual calls.
The ST7 protocol supports direct data transmission between stations. During this type of communication, data is always exchanged via the polling control center TIM. - Polling with time-slot procedure mode is used on a wireless network on which the use of the radio frequency assigned by the registration authorities has to be shared with other operators. Typically, each operator has six seconds per minute to exchange data with its stations. Once this time has elapsed, the frequency must be enabled for the next operator. During the allocated time slot, this type of polling operates in the same way as standard polling.
The ST7 protocol supports direct data transmission between stations. During this type of communication, data is always exchanged via the polling control center TIM.
Network configurations and topologies
All networks and all transmission media can be combined in any way in a telecontrol project – both with each other in "node structures", as well as in parallel in star topologies or in redundant configurations.
The graphics below show a selection of different topologies that can be implemented with the telecontrol components.
Basic topologies
Differently structured telecontrol networks can be implemented in the wide area network (WAN) based on the following four basic topologies.
Media versions
Depending on the support provided by the selected telecontrol protocol, various transmission media are available for these basic topologies, for example, dedicated line, private wireless networks, mobile wireless networks, dial-up networks (wireless/landline), DSL over Internet.
Some of these media versions are shown here using the example of the star topology.
Combinations of basic topologies and media versions
Through a combination of several basic topologies of the same or different media versions, it is additionally possible to design more complex network topologies, even with redundant communication paths. This allows optimum adaptation to process requirements and to the existing infrastructure.
