Chapter 6 Applied Instructions Note: When several interrupts occur simultaneously, the interrupt task whose pointer number is smallest is executed first. The PLC completes the on-going interrupt, and then execute other interrupts according to their pointer numbers. For example, during the execution of I400 interrupt, if I500 and I300 occur simultaneously, the PLC executes the I300 interrupt (smaller pointer number) after executing the I400 interrupt. 6_ 6-167 Interrupt Maskable interrupts Description Bit No. number SR I601 Timer interrupts 1 (unit 1ms) SR632 0 I602 Timer interrupts 1 (unit 1ms) 1 I603 Timer interrupts 1 (unit 1ms) 2 I604 Timer interrupts 1 (unit 0.1ms) 3