Digital Modules
3-33
Programmable Logic Controllers S7-300 Module Data
A5E00105505-03
Hardware interrupt lost
In an interrupt has been buffered for a channel and another interrupt occurs on that
channel before it has been processed by the CPU, a diagnostic interrupt “hardware
interrupt lost” is triggered.
More interrupts on this channel are not acquired until processing of the interrupt
buffered on this channel has been executed.
Interrupt-triggering channels
The channel triggered by the hardware interrupt is entered in the start information
of the OB 40 in the OB40_POINT_ADDR variable. Figure 3-9 shows the
assignment of the bits to the local data double word 8.
Byte Variable Data type Description
6/7 OB40_MDL_ADDR WORD B#16#0 Address of the interrupt
triggering module
From
8
OB40_POINT_ADDR DWORD See
Figure 3-9
Display of the interrupt
triggering inputs
1
Bit no.
3130
29 28 2726
LD 8
1
LB 8
25 24
Edge change channel 2
Edge change: Channel 0
Edge change: Channel 7
LB 11
0
1
Edge change: Channel 1
11
LB 10
1
2322
21 20 1918
1
LB 9
17 16
11
Edge change channel 10
Edge change: Channel 8
Edge change: Channel 15
Edge change: Channel 9
reserved
Figure 3-9 Start Information of OB 40: Which Event Has Triggered the Hardware Interrupt at the Limit
Value