ICC OPC-PRT3, Инструкция по эксплуатации, Страница: 83 / 115

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Figure 69: PLC Program after MSG Instruction Configuration
6) Assign a tag to the XIO element.
a) Double-click on the XIO element located to the left of the MSG block. Type in N20:0/15
(MSG instruction’s enable bit). This configuration causes the MSG instruction to
automatically retrigger itself when it completes. While this is acceptable for the purposes of
this example, it can produce high network utilization. In actual practice, it may be desirable to
incorporate additional logic elements to allow triggering the MSG instruction at a specific rate
or under specific conditions.
7) The program is now complete. Refer to Figure 70.
Figure 70: Completed PLC Program
8) Save, download, and run the program.
a) To view the function codes being read from the interface card, double-click the data file N18
under “Data Files” in the controller organizer view. 25 function code values starting at
register #2050 are being continuously read from the interface card and placed in the 25
sequential offsets of N18 starting at N18:1. Refer to Figure 71. We can see that N18:9
(register 2058 / output frequency / function code M09) has a value of 2525 (25.25Hz),
N18:12 (register 2061 / output voltage / function code M12) has a value of 610 (61.0V), etc.