Abstract— SCADA (Supervisory Control And Data Acquisition) systems represent applications trought which we can collect datas from a system in order to control and monitorise that system. So SCADA is in fact technology that gives the user the posibility to acquire data from one or more remote equipments and send a limited set of control instructions to those equipments. The purpose of this writing is a study of SCADA systems exemplified by a heating system. Keywords— control, industrial process, informatic system, monitoring, real time, SCADA. I. INTRODUCTION UMERICAL process control equipment represented a significant step towards reducing the gap between outstanding results offered by automatic systems theory and techniques applied in practical management of industrial processes. The particularities of programming computer systems for monitoring and/or management in real-time industrial process are determined by the following conditions: 1) the posibility of the system to respond instantly to random signals that come from the process; 2) the ability of the system to receive data directly from the process and / or transmit them directly into the process by non-standard peripherals (analog to digital converters, digital-to- analog converters , etc) 3) the requirement for "the real time" is when the system is busy with some proper operation of a particular event, to be strictly correlated with the time and other events occurring in the industrial process; 4) to solve the contradiction between the ability of the system to perform at some point one program and the process to be "served" in n points simultaneously; in other words, the system must face simultaneous development of different specific parts of the process; 5) the possibility of programming all types of process (continuous or discrete); 6) the existance of elements of efficient testing and debugging of the programs [1]. Therefore, to schedule a real-time application, the programming language used must contain three types of instructions: 1) Instructions that enable programming the mode in which the events start in the process; 2) Instructions that specify where the events take place in the process; 3) Instructions that refer to time or time range in which the events take place in the process [2]. The instructions from the first category form a set of basic options that can be used without real time from the system. The other categories of instructions are specific to work in real time and form an extension of the basic language. They can be obtained via the interrupt system mode (event venue) and real-time clock (time or time in which the events take place in the process) SCADA is the technology that allows the user to collect data from one or more remote equipments and send a set of limited instructions to control that equipment. A SCADA application has two elements: 1) The process/system/machinery you want to monitor a control—this can be a power plant, a water system, a network, a system of traffic lights, or anything else. 2) A network of intelligent devices that interfaces with the first system through sensors and control outputs. This network, which is the SCADA system, gives you the ability to measure and control specific elements of the first system [3], SCADA include the operator’s interface and concrete data of manipulation of the application. SCADA has functioned for a long time independently from other numerical systems and the fact that he was a real-time system, was not important. More and more SCADA systems appear that run on schedule or on request. Today SCADA combines both elements in real- time and pre-programmed operation. For the SCADA systems real-time operation means updating control systems to change in the process. Strictly speaking, real-time command is the one that do not let the system to have a dead time between the reception of the process measurement and the control signals. In reality, all control systems introduce some delay [4]. Those who place no measurable effect delays are generally known as real-time systems. CONTROL AND MONITORING OF SISTEMS HEATING WITH SCADA Cristina BALA 1 , Valentin MULLER 2 , Mihaela POPA 3 1 Universitatea “A. Vlaicu” Arad, cris_bala@yahoo.com 1 Universitatea “A. Vlaicu” Arad, valentinmuller7@yahoo.com 1 Universitatea “A. Vlaicu” Arad, mihaela2popa@yahoo.com N ANNALS OF THE ORADEA UNIVERSITY Fascicle of Management and Technological Engineering ISSUE #1, MAY 2014, http://www.imtuoradea.ro/auo.fmte/ 143