ML1000 Washing machine program

pdf of version 2 rev1

zipped pdf printout

Hi Ken,

After studying your washing machine, I have a few questions to ask.

1. Is all faults gengerates by plc are latched.
File No.2 Rung 9 you use unlatch to clear overflow trap.

2. Using two push buttons to perform different task.
File No.2 Rung 1. you use start and reset button to advance step. Will you explain when can we use this. Do you have to make sure that in your program the start and reset button never be pushed at the same time. What is going to happen if we can not push the buttons exactly at the same time.

3. Planing
I would like to know how this program was planned. I realised that you did this "on top of your head" as you said. But if you would teach beginner (eg me) to plan. what would you do.

File No.2 Rung 9 you use unlatch to clear overflow trap.

Click to expand...

An overflow will fault the processor, sometimes this is a good thing, sometimes not. In my case I'm not doing anything that would cause an overflow, but threw in the logic anyway.

2. 2. Using two push buttons to perform different task.
File No.2 Rung 1. you use start and reset button to advance step. Will you explain when can we use this. Do you have to make sure that in your program the start and reset button never be pushed at the same time. What is going to happen if we can not push the buttons exactly at the same time.
.

Click to expand...

You notice that when I want PB1, I have a not PB2, and when I want PB2, I have not PB1, so that I get the input I'm looking for.
It doesn't matter if both are not pushed at the same time, because the timer doesn't start timing until they are.

3. Planing
I would like to know how this program was planned. I realised that you did this "on top of your head" as you said. But if you would teach beginner (eg me) to plan. what would you do.

Click to expand...

Start with a flow chart of the application. Then decide what outputs are on for each step. Then what causes these outputs to come on.

I've been doing this for a while, and have developed my own way of doing things. Perhaps someone else, can give a better example.
I'm a lot better at doing than teaching, I have a hard time explaning myself at times.


Hope this helps

Basic "tools" (?) of program ??

Ken,

In your washer program did you rely mainly on sequencer (s) or on timers to activate outputs and control steps.

Why did you choose or rely on one more than the other (if that is the case) ??

Obviously I have not opened it up yet, am still figuring it out on my own. Don't worry will open if get too exasperated.

Have just started learning sequencers.
Am using tomer to control duration of each step only
-- with another timer to control the pause period
- don't want to do hemorrage on motor doing instant reverse.

Am trying to make the washing machine program as real world as possible so there are a couple of permutations or twists I need to figure out. Even IF sequencer is not the best choice I need to figure out why. Sometimes very important to know what not to do.

While I have you.

On the sequencer (SQO - Allen Bradley Micrologis 1000) can I designate the destination as a bit file(s) as opposed to an output file. That way I can conserve on outputs. An example of wasting one is on soak cycle - the machine is just sitting there -- why waste an output terminal for the soak cycle??

Dan Bentler

Hi Dan,
I used retentive timers for each timed step, the drain and fill were event driven (switches), and a counter to sequence the steps.

Why did you choose or rely on one more than the other (if that is the case) ??

Click to expand...

It's a method I've used a lot and I'm very familiar with it, there may (probably is) a better way.

why waste an output terminal for the soak cycle??

Click to expand...

How is the operator going to know that the machine is soaking and not just off?

Ken,
I am wondering whether you or someone in the group send me the screen shots of the ladder logic for the washing machine...i do not have rslogix on my computer.

I really appreciate if someone help me out.

Look at the right hand side of this page.
You can download the software for the 10 point controller for free.
You have to register first.

oops sorry, I guess it won't run on a 10 point controller.
Look up there is a zipped Pdf File
Good Luck.

post #16 has the program in pdf format.

How's bout a pic of the washing machine...



Andy

How is the operator going to know that the machine is soaking and not just off?

Click to expand...

Ken, like any house-frau knows, it is not off if the little timer thingy has not turned all the way around to "OFF". Most real-world washing machines do not have an output for the soak cycle, only a timer period.

Just kidding, you have done an excellent programming job. Of course yours is an imaginary machine, as it would not be very cost effective to use a PLC in place of a $40 timer. Not yet, but the day is approaching....

Then there are the Water Temperature Settings: Hot, Warm, Cold. I see Hot and Cold in your program, but no Warm... Most U.S. machines now have combinations of temperatures, like Hot Wash, Warm Rinse, and so on.

Lancie1 there are a lot of features missing on this machine. The program was just something to do one weekend. I should have called in an industrial soil extractor instead. The machine my wife uses now actually has analog inputs! When we bought it there were a couple of high end machines ($$$) with text interfaces, and you could set all sorts of stuff, wash time, rinse time, delayed start etc...

In my opinion, the one shot instruction is necessary for HH level alarm reset. The new reversion program can not reset the noisy alarm

Three seconds after Reset puchbotton pressed, if the level stay HH, the alarm will be activated again. I think this is not the ideal RESET fuction. you can only wait the level back to normal.

Pdf

Hi Ken,
spot on programming.
How did you get the project saved as PDF ??

I used primopdf, you can downloaded it for free at www.primopdf.com

Once that's loaded, you open up your plc project, and print to the pdf print engine.

I have seen sequencers done a few different ways but not quite liket that. I like it!