Mihai Rata

Application with a XY-plotter controlled by PLC used in student laboratory works

In many specific laboratories the students use only a PLC simulator software, because the hardware equipment is expensive. This paper presents a solution that allows students to study both the hardware and software parts, in the laboratory works. The hardware part of solution consists in an old plotter, an adapter board, a PLC and a HMI. The software part of this solution is represented by the projects of the students, in which they developed applications for programming the PLC and the HMI. This equipment can be made very easy and can be used in university labs by students, so that they design and test their applications, from low to high complexity [1], [2].

Analysis of the deforming regime generated by different light sources, using reconfigurable system - CompactRIO

This paper presents a study of the deforming regime generated by different light sources. We use several kinds of light bulbs: incandescent, gas discharge lamp and light-emitting diodes. For the acquisition and the analysis of voltage and current signals we use reconfigurable CompactRIO system from National Instruments. It allows real time monitoring of both voltage/current signals and deforming regime indicators.

Efficient gate drive circuit for IGBT

The IGBT is one of most important power semiconductor device for converter applications from several hundred watts up to 2 MW. This is used only in commutation mode and combines advantages of a MOSFETs (high gate resistance) and bipolar transistors (small collector-emitter drop at saturated condition). When we use IGBTs for converter application its very important to choose an optimum solution for circuit driver. Now many circuits driver have some protections for IGBT incorporated. This paper presents a study on the performance of one circuit driver (Skyper32 PRO driver, from Semikron), some experimental results and conclusions about this.

A solution for study of PID controllers using cRIO system

Designing ACS (automatic control system) in closed loop was more an art than science until the Industrial Revolution, when mathematics began to be used (for the first time in the middle of nineteenth century) in stability analysis of ACS in closed loop. Currently, the automation of industrial installations is carried out either using PLCs (Programmable Logic Controller) or using PACs (Programmable Automation Controller). The latter incorporate the advantages of PCs (software capability) and PLCs (PACs are as robust as PLCs which make them useful in industrial environment). Along with PXI systems, Compact FieldPoint and Compact Vision System, also based on LabVIEW Real-Time technologies and LabVIEW FPGA, CompactRIO (cRIO) systems (from National Instruments) belong to the Programmable Automation Controllers category (PACs). This paper proposes an application that highlights the principle of closed-loop control (using PID controller) of a DC motor speed, through a CompactRIO system. For students, its very important to understand how work these controllers and how important its to make an optimal tuning.

A solution for the study and understanding of PID controllers

Today, in most automatic process control applications in industry are used PID controllers. It is very important for the students to understand how work these controllers and how important it is to make an optimal tuning of these controllers. This paper presents a solution which permits to study and understand PID controllers. This solution is a closed-loop speed control system in a centrifugal load application which permits air flow control by fans motor speed adjusts using a VFD. The PID controller is implemented in a PLC that control the VFD by CANOpen protocol.

Simulation and PLC control of an electromechanical actuator with volatile liquid

The paper presents the study and operating control of an electromechanical actuator with volatile liquid (EAVL). The paper proposes a practical approach for EAVL displacement control using a PLC technology and a linear potentiometer transducer. Proposed electromechanical actuator has two essential features: low linear displacement and high strength. The electromechanical actuator is a technical dynamic system that can be investigated through transfer functions. In this regard, the step response of the EAVL was analyzed, the transfer functions (experimental and theoretical) and time constants values were identified for different quantities of volatile liquid used inside of actuator. Through transfer functions were analyzed parameters characterizing the dynamic properties of the system: delay, transient regime speed, response time and the coefficient of amplification. Also, the results of the evaluation through finite element method are analyzed. The EAVL behavior on the temperature and pressure variation is presented.

Temperature control solution with PLC

In this paper, different solutions for power supply of a resistance used for the liquid heating were analyzed. The authors propose the best solution in terms of reliability, harmonic pollution of power network and precision temperature control. For this were used: the XC-CPU101 PLC, the XV102 HMI (Human Machine Interface) from EATON. The temperature control used a PID controller based on PLC and it was observed by HMI. Desired temperature is set by the user using the HMI and the PID controller, within the PLC, will try to minimize the error value as the difference between desired temperature and measured temperature by adjustment of a control variable.

A solution for study of positioning control of two axes

For engineering students, it is very important that the laboratory work should be more practical, in order to provide an experience closer to the real world applications. In this paper, a solution to study the positioning control of two axes is presented. The solution is made with a PLC, two kind of HMI, a drive capable to manage two axes with high performance positioning, an induction motor and a brushless motor. The industrial communications used in this application are ProfiNET and ProfiBUS. The proposed solution can be used by the students to develop software applications, from low to high complexity.

Study solution of induction motor dynamic braking

The three-phase squirrel-cage induction motors are mostly used in industrial drivers since they are rugged, reliable and economical. The DC bus voltage of the AC drives increases when the motor regenerates. The regenerating energy is usually released in the form of heat. A short mathematical description and the experimental results for different cases of dynamic brake regime are presented in our paper. This solution is recommended for student use and laboratory work to improve understanding of dynamic brake working.

The study of harmonics from dimmable LED lamps, using CompactRIO

LED lamps have many advantages in comparison with incandescent lamps, halogen lamps and compact fluorescent light lamps. Although produce harmonic pollution due to the drivers used for their power supply, they are becoming increasingly used nowadays. This paper presents a study of the harmonics from dimmable LED lamps, using reconfigurable CompactRIO system. Various available dimmable LEDs were tested. With CompactRIO, we can rapidly build an embedded control and acquisition system that can analyses the harmonics from dimmable LED lamps.