How is the WAIT instruction used?

• A. The WAIT instruction always skips if no delay.
• B. The WAIT instruction is used to read a digital input into a Byte variable.
• C. The WAIT instruction is used when a robot program depends on signal status of a limit switch, proximity sensor, PLC, or other source. A timer tag can be used; waits for either I/O status to be true or for the timer to expire; whichever comes first.
• D. The WAIT instruction is used to pause until an external operator presses a button.

Answer: (C)

Waiting is used to synchronize the robot with something happening outside its own program. The instruction pauses the robot until a chosen external condition becomes true, such as a limit switch, proximity sensor, or a PLC signal. It can also include a timer, so the wait ends not only when the external input goes active but also when a specified time has elapsed. Whichever event occurs first—input true or timer expiry—the program continues. This lets the robot proceed as soon as the part-ready signal arrives, but also avoids getting stuck if that signal never comes by using a timeout. It’s not about simply reading a value into a Byte variable, nor is it limited to waiting for an operator button; it’s a general mechanism for coordinating with external signals and time.