What type of instruction holds the state of the output when the rung continuity changes to false?

The retentive bit output instruction is specifically designed to maintain the last state of an output even when the rung continuity changes to false. This characteristic is essential in control applications where the output must remain activated or deactivated based on a prior condition rather than just a direct or current input signal.

When using a retentive bit output, once the output is set to true, it will remain in that state even if the conditions that initially energized it no longer hold, until a specific action is taken to reset it. This makes it ideal for applications such as latch-and-hold scenarios where an output must persist regardless of the initial rung conditions being met.

In contrast, the other types of output instructions serve different purposes: momentary output instructions generate a temporary output pulse that only lasts as long as their conditions are true, standard output instructions turn an output on or off based purely on the rung conditions, and conditional output instructions activate outputs under specific conditions but do not retain states independently. Therefore, the retentive bit output instruction is the only choice that fits the requirement of holding the output state when rung continuity changes to false.