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

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

plc design - 10.6<br />

step4<br />

bottom LS<br />

step2<br />

step1<br />

step1<br />

FS<br />

step1<br />

flag up button<br />

step3<br />

step2<br />

step2<br />

step2<br />

top LS<br />

step4<br />

step3<br />

step3<br />

step3<br />

flag down button<br />

step1<br />

step4<br />

step4<br />

step 1<br />

step 3<br />

down<br />

motor<br />

up<br />

motor<br />

Figure 10.4<br />

<strong>Process</strong> Sequence Bits Without Latches<br />

10.3 TIMING DIAGRAMS<br />

Timing diagrams can be valuable when designing ladder logic for processes that<br />

are only dependant on time. The timing diagram is drawn with clear start <strong>and</strong> stop times.<br />

Ladder logic is constructed with timers that are used to turn outputs on <strong>and</strong> off at appropriate<br />

times. The basic method is;<br />

1. Underst<strong>and</strong> the process.

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

Saved successfully!

Ooh no, something went wrong!