STEROWNIK PLC NA PLATFORMIE RASPBERRY PI PROGRAMOWANY W ŚRODOWISKU CPDEV

Abstract

The paper presents a low-cost PLC controller prototype based on the popular Raspberry Pi hardware platform. CPDev programming environment, developed at Rzeszow University of Technology, is used to create control programs. CPDev virtual machine has been implemented in Raspberry Pi to make a runtime environment for control software. Input and output signal handling is achieved via Piface hardware module add-on. A smart home is presented as an example application, controlling window shades, lighting, ventilation and door lock. For testing purposes, a lab installation has been constructed with model of a family home. Control algorithms have been prepared in LD language which complies with IEC 61131-3 standard [11]. Three tests have been performed on this system. The first test verifies whether the control logic meets the requirements and works with acceptable cycle time. The second test involves CPU resources taken by the PLC during work. The third test shows how the temperature changes during operation of the control algorithm. The test results confirm that Raspberry Pi and CPDev environment can be used to control a simple installation of smart home, e.g. single-family home or a small office building. When new devices are installed at home, straightforward reconfiguration is possible by using the CPDev environment. Apart from running control algorithms, the presented system is powerful enough to execute concurrently other tasks, such as handling of remote access via WWW.