18: PROGRAM BRANCHING INSTRUCTIONS« FC4A MICRO SMART USER ’S MANUAL » 18-7DI (Disable Interrupt)EI (Enable Interrupt)Applicable CPU ModulesValid OperandsInterrupt inputs I2 through I5 and timer interrupt selected in the Function Area Settings are normally enabled when theCPU starts. When the DI instruction is executed, interrupt inputs and timer interrupt designated as source operand S1 aredisabled even if the interrupt condition is met in the user program area subsequent to the DI instruction. When the EIinstruction is executed, disabled interrupt inputs and timer interrupt designated as source operand S1 are enabled again inthe user program area subsequent to the EI instruction. Different operands can be selected for the DI and EI instructions todisable and enable interrupt inputs selectively. For Interrupt Input and Timer Interrupt, see pages 5-20 and 5-22.Make sure that interrupt inputs and timer interrupt designated as source operand S1 are selected in the Function Area Set-tings. Otherwise, when the DI or EI instruction is executed, a user program execution error will result, turning on specialinternal relay M8004 and the ERR LED on the CPU module.The DI and EI instructions cannot be used in an interrupt program. If used, a user program execution error will result, turn-ing on special internal relay M8004 and the ERR LED on the CPU module.Special Internal Relays M8140-M8144: Interrupt StatusSpecial internal relays M8140 through M8144 are provided to indicate whether interrupt inputs and timer interrupt areenabled or disabled.Programming WindLDRIn the Disable Interrupt (DI) or Enable Interrupt (EI) dialog box, click the check box on the left of Interrupt Inputs I2through I5 or Timer Interrupt to select source operand S1. The example below selects interrupt inputs I2, I3, and timerinterrupt for the DI instruction, and a 19 will be shown as source operand S1.FC4A-C10R2/C FC4A-C16R2/C FC4A-C24R2/C FC4A-D20K3/S3 FC4A-D20RK1/RS1 & FC4A-D40K3/S3— — — — XOperand Function I Q M R T C D Constant RepeatS1 (Source 1) Interrupt inputs and timer interrupt — — — — — — — 1-31 —Interrupt Interrupt Enabled Interrupt DisabledInterrupt Input I2 M8140 ON M8140 OFFInterrupt Input I3 M8141 ON M8141 OFFInterrupt Input I4 M8142 ON M8142 OFFInterrupt Input I5 M8143 ON M8143 OFFTimer Interrupt M8144 ON M8144 OFFWhen input is on, interrupt inputs and timer interrupt designated by source operand S1are disabled.DI S1**EI S1**When input is on, interrupt inputs and timer interrupt designated by source operand S1are enabled.DI S119The total of selected interrupt inputs and timerinterrupt is shown as source operand S1.Interrupt S1 ValueInterrupt Input I2 1Interrupt Input I3 2Interrupt Input I4 4Interrupt Input I5 8Timer Interrupt 16
