Publication 1766-RM001A-EN-P - October 2008
Programming Instructions Overview 95
• Address: N[N50:100]:10
• Description: In this example, the source of the COP instruction is
indirected by N50:100. The data in N50:100 defines the data file
number to be used in the instruction. In this example, the copy
instruction source A is defined by N[N50:100]:10. When the
instruction is scanned, the data in N50:100 is used to define the data
file to be used for the COP instruction. If the value of location
N50:100 = 27, this instruction copies 15 elements of data from
N27:10 (N27:10 to N27:24) to N7:0 (N7:0 to N7:14)
TIP
If a number larger than 255 is placed in N50:100 in this example, a
controller fault occurs. This is because the controller has a maximum
of 255 data files. In addition, the file defined by the indirection should
match the file type defined by the instruction, in this example an
integer file.
TIP
This example also illustrates how to perform a limit check on the
indirect address. The limit instruction at the beginning of the rung is
monitoring the indirect element. If the data at N50:100 is less than 10
or greater than 25, the copy instruction is not processed. This
procedure can be used to make sure an indirect address does not
access data an unintended location.
efesotomasyon.com - Allen Bradley,Rockwell,plc,servo,drive
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