1766-RM001A-EN-P MicroLogix 1400 Programmable Controllers ...

Using Interrupts 321STI User Interrupt Pending (UIP)Sub-Element Description Address Data Format Type User ProgramAccessUIP - User Interrupt Pending STI:0/UIP binary (bit) status read onlyThe UIP (User Interrupt Pending) is a status flag that represents aninterrupt is pending. This status bit can be monitored or used for logicpurposes in the control program if you need to determine when asubroutine cannot execute immediately.This bit is automatically set and cleared by the controller. The controllercan process 1 active and maintain up to 2 pending user interruptconditions before it sets the lost bit.STI Timed Interrupt Enabled (TIE)Sub-Element Description Address Data Format Type User ProgramAccessTIE - Timed Interrupt Enabled STI:0/TIE binary (bit) control read/writeThe TIE (Timed Interrupt Enabled) control bit is used to enable or disablethe timed interrupt mechanism. When set (1), timing is enabled, whenclear (0) timing is disabled. If this bit is cleared (disabled) while the timeris running, the accumulated value is cleared (0). If the bit is then set (1),timing starts.This bit is controlled by the user program and retains its value through apower cycle.STI Auto Start (AS)Sub-Element Description Address Data Format Type User ProgramAccessAS - Auto Start STI:0/AS binary (bit) control read onlyThe AS (Auto Start) is a control bit that can be used in the controlprogram. The auto start bit is configured with the programming deviceand stored as part of the user program. The auto start bit automaticallysets the STI Timed Interrupt Enable (TIE) bit when the controller entersany executing mode.Publication 1766-RM001A-EN-P - October 2008