Hi... I need information about sequence tables... I don´t speak English very well, excuse me if I have misspelled... whatever.. If anybody can give me information about this topic, i thank you so much... In internet don´t exist information about it..!!! Thank you of advance...

 

Sounds like it might be referring to a drum type instruction (AB calls their implementation sequencers).

In the old days, the operations of a machine might be controlled by a drum with holes in rows around it. A limit switch would be positioned over each row and you could put pegs in the holes (an alternate type used cams instead of the holes and pegs). The drum would rotate continuously or step based on time or events, and each limit switch would control one function of the machine, solenoid, motor, etc. Very much like a configurable version of the motor timer in your washing machine at home.

So many PLC's have "Drum" instructions that emulate that type of operation.