Automating Manufacturing Systems - Process Control and ...

plc advanced functions - 16.16
program file 2
S2:1/15 - first scan
MOV
Source 3
Dest S2:31
MOV
Source 500
Dest S2:30
program file 3
ADD
SourceA I:000
SourceB N7:10
Dest N7:10
Figure 16.16
A Timed Interrupt Program
Interrupts can also be used to monitor a change in an input. This is useful when
waiting for a change that needs a fast response. The relevant values that can be changed
are listed below.
S:46 - the program file to run when the input bit changes
S:47 - the rack and group number (e.g. if in the main rack it is 000)
S:48 - mask for the input address (e.g. 0000000000000100 watches 02)
S:49 - for positive edge triggered =1 for negative edge triggered = 0
S:50 - the number of counts before the interrupt occurs 1 = always up to 32767
Figure 16.17 shows an interrupt driven interrupt. Program 2 sets up the interrupt to
run program file 3 when input I:002/02 has 10 positive edges. (Note: the value of 0004 in
binary is 0000 0000 0000 0100b, or input 02.) When the input goes positive 10 times the
bit B3/100 will be set.