1 hint

wanted to learn so i dove right in.bought plc and software.trilogi per an instructor at local college.have about 6 pages of different diagrams for a sequential program but it illudes me how to call the same output more than 1 x e.t. slow fast slow; out1,out2,out1. any insite appreciated. have enrolled to study plc but class does not start till 1/03.

The simple answer is, you DON'T address an output (or an internal coil) more than once in a program.

This sort of thing is what makes sequence logic such a problem for students to grasp.

You will have only one coil with the output on one rung, but there will likely be several branches to that rung, each represnting a different set of conditions, related to the step, that the output is on.

There are many threads in this forum (and more in the archives) that deal with sequencial control. Do a search for them, and study them carefully.

There are many ways to approach this problem, almost as many ways as there are PLC programmers. Some use less code, some follow one kind of method of diagramming the sequence, other follow different methods. They all work (eventually).

You've got a PLC. Now get to Carnegie Hall.

(trilogi PLC? Never heard of it. Hopefully it didn't set you back much).

One clarification on something that confuses a lot of beginners: You should only use the COIL for each output or internal coil once, but you can use as many CONTACTS from each coil as often as you want. This is analagous to changing from a single pole relay (one coil, one set of contacts, i.e. one pole) to a two pole, to a three pole, to a four pole, to a .... This is one of the advantages of a PLC over hardwired relay logic - you can add poles and change from normally open to normally closed at will.

Allen, Trilogi is a tiny little PC board OEM-Type programmable controller. It's not quite the industrial type PLC you would see at a plant, but for learning programming it should work.