title: Timers in PLC - Structured Text
body: <p>How do timers work in PLC Structured Text (ST)? How do we declare them?</p>
  
  <p>I've been studying a standard of PLC (IEC 61131-3), and they do not speak about timers in ST. I know the great majority of PLC programmers do them in ladder logic, but in this particular case I really need to declare timers in ST.</p>
  
  <p>I am using a Rockwell PLC.</p>