AUTOMATION OF PLC PROGRAMMING WHEN IMPLEMENTING ALGORITHMS OF GUARANTEEING CONTROL

Abstract

During developing programs for programmable logic controllers (PLCs) the concept of model-oriented design is increasingly used. In particular, usage of Simulink PLC Coder is giving the opportunity to get SCL program code
from Simulink model which contains certain dynamic elements. Then, for example, this SCL code can be transformed to functional blocks of the Simatic S7-300 (VIPA 300) PLC. This significantly reduces the time
required to develop code in the language of SCL and reduces requirements for specialists’ qualification when developing control systems. In this article we provide an example of PLC programming automation when
implementing algorithms of guaranteeing control (AGC). For certain types of technological processes it is typical to contain monotonically increasing function of the effectiveness with fixed one-way restriction in regulations. For
example, in the grinders, presses, extruders the load current of the drive is stabilized using the change of feed. Energy efficiency of these plants will increase with increasing of the set point (SP) to the controller of the drive load
current stabilization loop. However, an increase in SP increases the probability of triggering appropriate protection, for example, as a result of random changes in the properties of raw materials. Therefore, to avoid this accident, the
power of driving motors is often unreasonably overrated. And in this case they are used with currents equal to the half of rated.Systems of guaranteeing control (SGC) are used to solve the contradiction between the need to improve
the efficiency and increasing probability of an accident.