5. An industrial robot performs a machine loading and unloading operation. A PLC is used as the robot cell controller. The cell operates as follows: (1) a human worker places a workpart into a nest, (2) the robot reaches over and picks up the part and places it into an induction heating coil, (3) a time of 10 seconds is allowed for the heating operation, and (4) the robot reaches in and retrieves the part and places it on an outgoing conveyor. A limit switch I1 (normally open) will be used in the nest to indicate part presence in step (1). Similarly the presence of a part on the induction heating coil in step (2) and the outgoing conveyor in step (4) will be detected by I2 and I3, respectively. Output contact O1 will be used to signal the robot to execute step (2) of the work cycle. This is an output contact for the PLC, but an input interlock for the robot controller. Timer T1 will be used to provide the 10 second delay in step (3). Output contact O2 will be used to signal the robot to execute step (4). Construct the ladder logic diagram for the system.