ACTUATOR-SENSOR LEVEL. COMMAND AND CONTROL OR
Integra equipment located at the foot of the process. The apparatus of this level consult with limit switches and signal transmitters and control process, following the established program, actuators and markers. At this level is where there is control of the switching sequence of the contactors and valves, interlocks and surveillance for the protection of personnel and machines as well as registration notices and operational disruption.
Features:
- The current trend suggests the use of sensors with communication skills to replace signals 0 / 4 to 20 mA.
- Using RS-485, RS-422, RS-232 and TTY.
- These sensors and peripheral equipment connected to a "field bus" to carry information to the controller (eg PLC).
- Is characterized by processing information in a very safe, very short times, high traffic on the bus and short messages.
- Transparency in the bus for communicating equipment from different manufacturers is ensured by adopting communication standard.
- This new series of "smart sensors" initially had a high cost compared to analog equipment. Today, the price difference is not significant.
OR FIELD LEVEL AUTOMATION CONTROL GROUP
Contains PLC managing the technologically interrelated process areas (eg assembly lines, transportation lines, complex machines, etc.).. The data from the PLC equipment and higher levels of automation are distributed, prepared and timely transmission, depending on events, to the automatic level control and regulation. The PLC controls the level of group gather data and compressed for delivery to the controller and senior teams. Thus it is possible to collect, for example, data for a list of operation, to record such information at the end of a shift or to deliver higher levels of automation for statistical evaluation.
Features:
- There is one or more main controllers called "master".
- The Master regulates the exchange of information contains fieldbus and control program of the plant.
- The master may be a PLC or industrial computer.
- The master must have a high information processing speed and memory.
- Must have communication interfaces or modules that allow communication with other computers or networks of other industrial manufacturers.
- Is recommended capacity "redundant" for critical processes.
CELL LEVEL OR CONTROL OF PRODUCTION AND PROCESS
It governs the entire process. It collected the data acquired at lower levels, are stored and conditioned for computer processing in the level of company management.
At this level of automation displays all process operations and can be manually intervene in it. Displayed, message list and evaluate operation and disturbance.
Features:
- Based on computer use (for use as station operator) with software such as SCADA (supervisory control and data acquisition).
- Is represented in graphical and dynamic behavior of the plant.
- The operator station is connected to the controller. / SCADA software is an "open architecture".
- Saves installation costs quipos peripherals.
- Allow communication to higher level networks such as Ethernet type administration, Novell, etc..
MANAGEMENT OR ADMINISTRATIVE LEVEL
At this level, computers are responsible for administrative and commercial functions for the entire process. They deliver primary data (eg number and type of product being manufactured) teams in the lower levels and, based on data acquired at these levels, compiling statistics for the charge of directing the process (for example, manufactured product relationships , rate of defective products, machine loading, etc.)..
The exchange of data between PLC and equipment from the lowest levels of automation can be done through the local network bus (Modbus, Profibus, etc.).. Ethernet is recommended at higher levels where they exchange large amounts of data.
Requirements for different levels Fig.
... finally, what basic features an industrial network must meet?
An industrial network must meet the following basic features:
Optimized - impiemenféción alternatives for each application.
Standardized - Ethernet, Modbus, Profibus, AS-Interface
Open - Independence of the origin of technologies for customers.
Accepted - Applications implemented and tested.
Forward-looking - and support continuous innovation.
Example of Standardized Control System SIEMENS
