SattLine looks the same, works the same, and has the same functionality no matter the application and system size. Thus, you can grow with the same system without replacing or reconfiguring anything which is already done. The system consists of both a software and a hardware part.
The software architecture is build up of configuration, programs, libraries and modules.
Modules
SattLine control programs are built by designing and assembling modules (objects). Lower level modules implement process objects like valves or basic functions like event detection.
The modules are stored in libraries containing graphics and program code. Basic objects can be used to form higher hierarchies like a mix tank, raw material intake, etc.
The software reuse enables fast program configuration, high quality development, and consistency, with kept flexibility.
The total application is called a program configuration which contains all programs for the plant. The configuration is split up into programs and libraries.
Program
A program is a hierarchical module collection of graphics, equations, variables, etc. The program can be distributed so that the station or controller can execute several programs.
A program can refer to libraries for module and data type definitions. The programs can also exchange information.
Library
A library is very similar to a program, but is only used to define modules and data types. Libraries may refer to other libraries and can be used by many programs.
Communication
The communication between the stations and the controller (within a program) is automatically set up by the system. There are integration functions like database communication via ODBC or program communication via OLE/OPC. Other Windows programs can be started from commands inside SattLine.
The hardware architecture is build up of the user interface, the control system and communication.
User interface
The user interface consists of four license types that run on Microsoft Windows and on PC/Intel systems.
The Workstation can be used for supervision, programming, maintenance, data storing, etc. All users have the same interface and interaction principles. A sophisticated privilege system ensures a safe workplace. The Workstation is available in different licenses sizes. They have the same functionality, but differ in application size.
The Viewer station is a low cost license limited for a few hours of operation after each start and without programming.
The Local station is a local operator station license for shop floor control. The license is limited in size and has no programming.
The Programming station is a license for programming and testing only.
Control system
The control system is modular and mounted on a standard DIN-rail. The system consists of modules like power supply, CPU, Ethernet communication, Fieldbus and serial communication. These modules can be freely combined.
The CPUs are available with varying memory and speed. All CPU types are compatible with the same functionality which makes it easier when upgrading.
The I/O system is based on three module types: adapter, terminal base and electronics. The I/O modules are available as digital, analogue, pulse and combined input and output. Several terminal bases are offered. The small footprint facilitates a very compact installation.
The I/O can be installed centrally or distributed. Thereby, the need for field cabling and documentation is reduced. The I/O modules can be changed on-line and the I/O system can be set to fail-safe mode.
Communication
The communication between the different SattLine nodes is based on MMS and standard Ethernet (single or redundant). Co-operation and integration with foreign equipment and programs is enabled through special functions. There are various communication protocols available like Profibus, COMLI, SattBus, ABDH+, etc.
SattLine Functions
SattLine contains a number of libraries. Modules in the libraries are used to solve general functions to provide process control as required from a DCS system.
The modules describe control solutions at different levels. Modules for physical objects like valves or motors, modules for analogue control algorithms or special function modules are natural parts of the SattLine libraries.
The modules include functions like alarm and event management, history logging and journal handling, control loop modules, report configuration modules, I/O configuration modules, etc.
Generally, a module can contain, besides control algorithms through sequences and equation blocks, variables and parameters for these algorithms and also graphics for presentation and interaction as well as other modules.
Alarm and Event Management
Changes in process status requires fast action by the system and the operator. This is handled by the event and alarm handling functions.
Alarms as well as events are not restricted to a change of a variable in the system, but also have further information as Tag, Event text, Severity, Class, Type of event, Time filters and Status text.
The time stamped events can be shown in different lists, printed on different printers or acknowledged/logged in different workstations.
For quick action, an event can initiate a process command or pop up a window containing more information or instructing the operator how to act.
Acknowledgement of events can be done under protection by user privileges.
History logging
Historical data can be logged on one or several workstations as a journal file on disk.
The journal can contain history data as well as single snapshots of data or manually entered data. Operation as read, write, etc. on the journal can be performed from any workstation or process controller.
A journal contains data marked with time and tag. Integer, real, Boolean, string variables as well as user defined data types (records) can be stored. The storage is either done cyclically or event triggered or a combination. Different data can be stored in the same journal e.g. batch journal containing events, history trends and reports related to a specific batch. Journals can be presented as curve diagrams.
Control Loops
PID modules and supporting modules make it possible to create cascade-, feed forward- and split range control loops.
The PID function has anti reset windup facility, bumpless transfer between manual and automatic modes, low pass filter for the derivative part of the PID, autotuning with gain scheduling and dead time control function. As special modules fuzzy control for the case of one to many inputs and outputs, stiction compensator - a control function for compensation of static friction in control valves and a control loop performance monitor for detection of oscillations are available. For the analogue signals, functions as scaling, filtering, linearization, limitation, integration and differentiation are possible.
Other modules for generation of set point ramps and other profiles, combining PID’s via multiplexes or max./min. selectors or three point controllers with feedback are part of the control loop library.
Interaction of the control loop function is done in pop-up windows. Standard windows are bargraphs, trend curves and parameter list presentations.
Time channel modules, automatic check of feedback signals, time controlled alarm activation and object runtime supervision
- Time channel modules are used for periodic starting and stopping of process objects according to the system clock, weekdays, holidays, etc.
- Automatic check of feedback signals (ACOF) from e.g. valves can be supervised by standard modules.
- Time controlled alarm activation according to different alternatives e.g. while opening or while closing are available.
- Object runtime supervision (RUTI) is a function supervising total runtime of process objects like motors.