UID (User Interrupt Disable) Ladder Logic Instruction

Definition

The (UID) User Interrupt Disable instruction is used in conjunction with a (UIE) User Interrupt Enable instruction. When enabled, the UID instruction prevents tasks with higher priority from interrupting the current task. The UIE instruction allows other tasks to interrupt the current task.

The task fault routine and the Controller fault handler are not disabled by the UID instruction.

Take caution; limit the amount of rungs placed between the UID and UIE instructions as a loss of communication may occur. In other words use only as needed.

The following image demonstrates the proper use of the UID and UIE instructions.

UID_UIE_Example