A Low-Cost Automatic Tester of PLC Functions

Abstract

In smart industries, a Programmable Logic Controller (PLC) is necessary to control system functions that confirm to work according to requirements. Furthermore, the testing of PLC functions should be carried out in a very short time with very good accuracy and high reliability, but at the lowest cost possible. This paper presents the Automatic Test Equipment (ATE) for PLC functions. The objective of this paper is to design low-cost ATE from commercially off-the-shelf (COTS) with ease of testing. A model-based systems engineering approach is used to design the tester. The ATE design uses the open-source Capella tool, which supports the Architecture Analysis and Design Integrated Approach (ARCADIA) method. The structural elements of the ATE system are the test controller, the switching relays, the system software, and the Human-Machine Interface (HMI), which is used to display the test results. The test controller executes the test program and controls the inputs of the PLC under test using the test patterns via switching relays. The responses from the outputs of the PLC are sent to the inputs of the test controller and compared with the expected responses. The results of PLC function testing are displayed on the HMI. The results show that the maximum speed of the ATE is 10 ms/pattern, and the total cost is under 140 USD.