What must be added to a single-cycle reciprocation control circuit to make it repeat its cycle continuously?

To enable a single-cycle reciprocation control circuit to continuously repeat its cycle, it is essential to incorporate another limit switch. When the existing limit switch is activated, it signals the end of the cycle. Adding another limit switch allows the system to detect when the movement has reached its endpoint or a specific position, completing one full motion cycle.

The newly added limit switch can act as a reset mechanism, triggering the control circuit to start the next cycle immediately after the previous one finishes. This method ensures that the system can perform its reciprocating motion without manual intervention after each complete cycle.

Other options, like adding another start pushbutton, would not inherently cause the cycle to repeat automatically, as it would still require manual activation for each new cycle. Incorporating another cylinder or a directional control valve (DCV) would change the mechanical or flow aspects of the system rather than contribute to the continuous operation of the existing control circuit. Therefore, the correct choice focuses on the function of limit switches in establishing a transitioning mechanism within the control logic.