AH500 Programming Manual set to ON. (b) If the external 24 V voltage of the first local extension backplane is abnormal, bit 1 in SR731 will be set to ON. 4. The external interrupts (I40~I251) If a peripheral device, e.g. a special I/O module, sends an interrupt request, the PLC will execute the specific interrupt task. 5. The timed interrupts (I252~I255) Timed interrupt 0 (I252): The default value is 100 milliseconds (1~1000 milliseconds). Timed interrupt 1 (I253): The default value is 40 milliseconds (1~1000 milliseconds). Timed interrupt 2 (I254): The default value is 20 milliseconds (1~1000 milliseconds). Timed interrupt 3 (I255):
The default value is 10 milliseconds (1~1000 milliseconds). The timed interrupt task is executed every specific period of time. For example, the timed interrupt task is executed every 10 milliseconds. The priority order is a follows.
6-148 Interrupt number Description Priority order I0 I/O interrupt 0 1 I1 I/O interrupt 1 2 I2 I/O interrupt 2 3 I3 I/O interrupt 3 4 I4 I/O interrupt 4 5 I5 I/O interrupt 5 6 I6 I/O interrupt 6 7 I7 I/O interrupt 7 8 I8 I/O interrupt 8 9 I9 I/O interrupt 9 10 I10 I/O interrupt 10 11 I11 I/O interrupt 11 12 I12 I/O interrupt 12 13 I13 I/O interrupt 13 14 I14 I/O interrupt 14 15 I15 I/O interrupt 15 16 I16 I/O interrupt 16 17 I17 I/O interrupt 17 18 I18 I/O interrupt 18 19 I19 I/O interrupt 19 20 I20 I/O interrupt 20 21 I21 I/O interrupt 21 22 I22 I/O interrupt 22 23 I23 I/O interrupt 23 24 I24 I/O interrupt 24 25 I25 I/O interrupt 25 26 I26 I/O interrupt 26 27 I27 I/O interrupt 27 28 I28 I/O interrupt 28 29 I29 I/O interrupt 29 30 I30 I/O interrupt 30 31 I31 I/O interrupt 31 32 I32 Communication interrupt (COM1) 33