Sequencer Exercise Problem

I am learning PLCs, and we are using the SLC 500 and Micrologix 1200 at school.

We have a "sequnecer exercise" that our instructors has challenged us or any other instructor to find the problem, and then of course to fix it.

While I don't have PLC gear at home, I could "post" or "upload" the program for you to look at.

(How do I upload the program?)

I have "stared" at the program, and am just not getting any where.

Looking forward to "posting or uploading" the file so I can get your assistance.

Steve

Welcome to the forum.

To upload the program you will need to zip it using a program such as pkzip. At the bottom of the advanced post window there is a button to attach a file. You browse to the file on your computer and select it. When you submit the post the file will be attached.

When you submit, attach a brief summary of the problem and what you think you need to do next or explain what part confuses you. There are many of us here who are more than willing to mentor and help students who are looking for a nudge in the right direction, we just don't want to do your homework for you.

So far it sounds like you are making a good attempt at solving it, so upload your file and lets see where we can help you.


edit: Also, do a search on the forum for previous threads dealing with sequencers. You might just find your answer there.

zip the program...click on attach files

Ooooo.... I love these!

Hurry up and post the problem!

Terry Woods said:

Ooooo.... I love these!

Hurry up and post the problem!

Click to expand...

Terry...its a AB...I'll get you a PDF..fast :site: if we ever get the program...

If I have done this correctly, the AB Micrologix 1200 PLC Sequencer program file is attached to this messaage.

One problem I figured out was that the program originally had only one "Control" location (R6:0), so I corrected that by having a different control for each pair of sequencers.

I have also thought that "masking" may be why one set of the lights (output)do not work when the lights (output) on rung 2 are on (true). I'm not entrily sure that is on the right track though.

As I watched the program run, it seemed that the output from rung 1 would "flicker" as the output on rung 2 would energize (go true).

I hope I have explained this so you can understand, as I am not completely familiar with all the terminology and just how to describe programs as yet.

Steve

This program only consists of rung 0. containing some anded inputs and 1-ton with 2-sqo's or'ed together. I do not see rungs 1 and 2 with the outputs you describe. Is this an incomplete program?

automfg -

Sorry, I uploaded the wrong file.

I don't have AB at home, so I re-wrote the program to LogixPro and am attaching that file now.

Do you have the .RSS file? you have loaded the .RSL

Here is the program.

For anyone that wants to view the pdf...

We still can not do much with this program for we do not know the values that fill the data tables for N7:0, N7:10, N7:20 AND N7:30

Please post the Values of
N7:0, N7:20 in Binary
N7:10, N7:30 in Decimal

All -

Here are the "N" data tables in "Decimal" (if not listed the value is zero):

N7:0 - 0 N7:20 - 0
N7:1 - 192 N7:21 - 2
N7:2 - 1152 N7:22 - 4
N7:3 - 384 N7:23 - 8
N7:4 - 192 N7:24 - 16
N7:5 - 2112 N7:25 - 32
N7:6 - 576

N7:10 - 0 N7:30 - 0
N7:11 - 4 N7:31 - 4
N7:12 - 8 N7:32 - 8
N7:13 - 6 N7:33 - 6
N7:14 - 4 N7:34 - 4
N7:15 - 8 N7:35 - 8
N7:16 - 6 N7:36 - 6

At school we were using a MicroLogix 1200 which is wired up to a "panel board" that has various switches/push buttons and lights/horn for input/output.

The "outputs" (and position on the board)for the panel board are as follows:

0 1 2 3 4 5 6 7
Horn Green Blue Green Red Blue Red Red
Light Light Light Light Light Light Light

8 9
Yellow Yellow
Light Light

10 11
Green Green
Light Light

The idea is to have one sequencer turn on outputs (lights) 1 through 5 and then to have the other sequencer to turn on outputs (lights) 6 through 11. (lights 6 - 11 represent a "traffic light").

Once again, thanks for all your help.

Steve

The mask FFFFh is all ones so it should not inhibit any of the outputs (in the pdf it may have already been corrected).

The other problem is that the timebase is way too freaking fast for traffic to keep up with unless you live in Dallas or something.

Either change the values in the data table that are written by the SQO to the timer presets to higher values so grandma can get her minivan through the intersection, or change the timebase of the timers to whole seconds, or both.

(N7:10-N7:16 go to T4:0.pre and N7:30-N7:36 go to T4:1.pre)

The common control element was a good find on your part by the way. Very good indeed for a beginner.


Paul