Which statement best describes the output energize instruction (OTE)?

• A. Energizes output when memory bit is 0
• B. Energizes output when memory bit is 1
• C. Energizes output always
• D. Never energizes

Answer: (B)

In ladder logic, the output energize instruction acts as a coil that powers the connected output only when the rung is true. The rung's truth depends on the controlling memory bit. When that memory bit is 1 (true), the rung evaluates to true and the OTE energizes the output. If the memory bit is 0 (false), the rung is not true, so the OTE does not energize the output. It doesn’t energize all the time or never; its state follows the controlling bit. For example, with a normally open contact representing the memory bit in series with the output energize, the output will energize when the bit is 1 and drop out when the bit becomes 0.