Example below represents a basic program. Example consists of one input device and one output device linked to the PLC controller output. Key is an input device, and a bell is an output supplied through a relay 00 contact at the PLC controller output. Input 000.00 represents a condition in executing an instruction over 010.00 bit. Pushing the key sets off a 000.00 bit and satisfies a condition for activation of a 010.00 bit which in turn activates the bell. For correct program function another line of program is needed with END instruction, and this ends the program. The following picture depicts the connection scheme for this example.