12.05.2014 Views

Automating Manufacturing Systems - Process Control and ...

Automating Manufacturing Systems - Process Control and ...

Automating Manufacturing Systems - Process Control and ...

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

plc advanced functions - 16.13<br />

A<br />

B<br />

X<br />

C<br />

TND<br />

D<br />

Y<br />

END<br />

When the end (or End Of File) is encountered the PLC will stop scanning the<br />

ladder, <strong>and</strong> start updating the outputs. This will not be true if it is a subroutine<br />

or a step in an SFC.<br />

Figure 16.13<br />

End Statements<br />

The one shot contact in Figure 16.14 can be used to turn on a ladder run for a single<br />

scan. When A has a positive edge the oneshot will turn on the run for a single scan. Bit<br />

last_bit_value is used here to track to rung status.<br />

A<br />

last_bit_value<br />

ONS<br />

B<br />

A<br />

B<br />

Figure 16.14<br />

One Shot Instruction<br />

www.PA<strong>Control</strong>.com

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!