Thank you all for taking the time to go through my post. I really appreciate your kind gesture. It seems I am still missing something out. I connected the PLC based on the explanations giving above, everything looked okay except that the indicator lamp which I wanted to control did not turn ON at all. My aim is to use a push button to ON an indicator light(24VDC/20mA). So I wrote a simple ladder program which I downloaded to the plc. Whenever I press the push button, the input- I:0/0 terminal(my push button is connected to this address) and the output- O:0/0 terminal (indicator lamp is connected to this address) indicator lights on the PLC turned ON, however my main indicator lamp did not turn ON. I do not know what I am doing wrong. CONNECTION OF THE INDICATOR LAMP TO THE PLC I connected one end of the indicator lamp to VDC0 and the other end to O/0 terminal. QUESTION If one presses a push button and the corresponding input and output terminals indicator light on the PLC turn ON but the actual load(indicator lamp in this case) does not turn ON. What does this kind of situation suggest and how can I go about the troubleshooting. Your suggestions and advice will be highly appreciated. Thank for the supports. Best regards