1 : According to the actual needs of the project , functional block planning, writing subroutines
In the PLC program subroutines are relatively Nanda Programmable industrial controller plc
independent control purposes for a number of specific preparation .
CALL subroutine call instruction is executed , such as when a subroutine
call if the condition is not met , the program scans performed in the
main program only , and not to scan this subroutine , which reduces scan
time unnecessarily . 2 : Use a word or double word reportedly gave DO
-point method to control output
In the application of PLC will
usually have a lot of output control , with the word, or double word
reportedly gave DO -point method to control the output can improve the
speed , as long as according to the requirements of practical
application, a reasonable allocation of the output address , change
control output control word , you can greatly reducing the number of
steps PLC program execution , thus speeding up the running Nanda china industrial automation plc speed of the PLC .
3 : Pulse trigger SET, RESET
PLC, using the SET command is executed only once , do not run this
command every scan , it is suitable for use with pulse output (PLS /
PLF) instructions for use . Some engineers ignore this problem , the use
of conventional methods to drive the SET command , inadvertently
increasing the PLC program scan running time.
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