PURPOSE: To prevent the occurrence of non-unification of operation between a plurality of control nodes.

CONSTITUTION: In an A-node 1, a lock signal and an unlock signal are inputted during execution period of a starting point T1 and a terminal point T3, but a finally received unlock signal is employed and outputted to a motor 4. Further, since a lock signal is inputted to the A-node 1, in subsequent execution, a lock signal is employed and outputted to the motor 4. When a series of signals are received by the A-node 1, a final control signal produces a lock signal. In a B-node 2, a lock signal is inputted in the middle of execution, a lock signal is first outputted to a motor 5. Further, two signals of an unlock signal and a lock signal are inputted to the B-node. Since a finally received signal is a lock signal, the B-node 2 employs a lock signal and effects execution during execution of a next program. A final control signal in the B-node produces a lock signal, and the final output signals of the A-node l1 and the B-node 2 are brought into coincidence with each other.