PC/PLC Based Simultaneous Running of More than One Laboratory Experiments Using WxPython and Pymodbus

Abstract

The Programmable Logic Controllers (PLCs) allow many industrial fields to input and output devices to be connected directly to their input and output points or modules. They also allow communication with more than one device through their communication ports. For these issues, the PLCs can be used to play an important role in supporting the education process. In this context, this paper introduces PC/PLC based laboratory platform to allow the simultaneous utilization of three experimental setups, one for Direct-On-Line (DOL) and star/delta starting of three-phase induction motor, one for the single-phase AC line controller, and one for the Inverse-Definite-Minimum-Time (IDMT) overcurrent protective relay. The first one allows the user to monitor and record the three-phase induction motor's current history under DOL and star/delta starting methods. The second one allows its user to understand the difference between the magnetic relay and Solid-State-Relay (SSR), run the AC line controller in ON/OFF, phase angle, and integral cycle modes of operations, and understand the basic construction and operation of soft starters. With the third setup, the user can test the various standard characteristic curves of the IDMT overcurrent relay. This platform uses three Personal Computers (PCs) and one Programmable Logic Controller (PLC). Each PC uses Wxpython (Graphic user interface toolkit of python programming language) and PyModbus communication utility to interface its related set-up to the central PLC.