Old Geezer needs Tutoring Nudge

Have not programmed a PLC in 5 years and the RUSTY NAILS are surfacing.
Practicing on my Logix Pro simulator ,while awaiting the CD to arrive for the learning pit , I decided to tackle the Silo Simulator.

Attached is my 4th attempt on getting the Silo Simulator to work properly I keep encountering two basic problems.

Attached is my drawing in word . doc format.

Would some body please offer me some constructive TUTORING ?

Your motor (conveyor motor) is currently told to run if you hit the start and stop if you hit the stop (standard start/stop logic). You have to incorporate the box position sensor and the fill sensor into this part of the logic.

Try getting the box to stop with the position sensor as a first step.

Brian.

Gee I was so proud of myself for finally figuring out how to get the full light to come on after 200 + tries and then you send me back to rung 000. New Ladder Logic attached with FULL LIGHT ON

Your Reply : Your motor (conveyor motor) is currently told to run if you hit the start and stop if you hit the stop (standard start/stop logic). You have to incorporate the box position sensor and the fill sensor into this part of the logic.

Try getting the box to stop with the position sensor as a first step.

Brian.

Nudge Question : Here's where the RUSTY NAIL fires up...How do I stop an action without pushing the stop button ?

promanen

You are using a contact on the motor starter to latch on the motor when the start button is pushed. Any contacts that would drop out in the rung feeding the output would cause the latch to release. I.E. Stop button, limit switch, photo-eye, etc.

Stopped the Conveyor belt and LOST My Light

Figured out how to stop the conveyor belt

Somehow I lost my FULL Light

Before I do call it a DAY....Can you answer me...How'd I lose my FULL LIght ?

Thanks

Pete

Looks like B3:1/1 will never make. The fill prox I:1/4 changes state (when full I guess) and the sol o:2/1 turns off. Since it is off then the conditions in rung 6 cannot come true. If you change the state to NC for O:2/1 in rung 6 then it should work. In rung 7 you only need B3:1/1 since you will have already checked those conditions in rung 6.


Good luck.

Glenn

OK , I made the necessary cuts and changes. It worked !
Thanks...now I need a can of Liquid Wrench and a 10 lb sledge to make it go after ithe box is full.

Thanks again for your help

promanen,

Try this change to make it go after the box is full. Also, you may want to simplify the logic, reduce the number of rungs, and add more commments.

Thanks for the info

I always start with an expanded ladder to make sure I have each and every bit on line . Once it works in long fashion then I reduce the number of rungs. Call it redundant , but I want to be thorough.

Again , Thanks for your help

Pete

Another DUMB rusty question...on Logix Pro simulator ...how do I add comments to the rungs ?
I've searched the toolbar but nothing sounds familiar.

I downloaded your changes but did not open or add them to my program.
First I need to find out where I'm going wrong in my thought and logic process. 5 years without working a program is starting to show the gaps in my brain.

I'm attaching a copy of my BLOCKAGE...what am I not seeing ?


Pete

You are double coiling...ie using O:2/0 twice, in first rung Belt conv prox must be off, in last rung Belt conv prox must be on...they counter act each other.

See if this helps. If I have it right then when you press start (the issue may be that you have to hold a momentary start button for a period of time before the motor latches...this depends)the motor will start and run until it gets back to the prox sensor position. Once at the prox sensor position it should start filling and fill light come on. Once full it stops filling and fill light goes off and full light is Latched ON. When you AGAIN press Start then FULL light goes OFF and motor runs until it gets to prox sensor position and starts over.

This is just an example to help you along, there are other probably better ways to do this.

OKAY Thanks , I'll try it in the morning

Pete

Pete,

To add comments to rungs in LogixPro, place the cursor on the rung number on the left side of the ladder, then RIGHT-button-mouse-click. A menu pop-up box will have 6 items: Cut, Copy, Paste, etc, and last, Edit Rung Comment. Left-click on "Edit Rung Comment", and a blank line will appear for your new entry. The limit is only 1 line of text per rung.

Hint on the conveyor motor re-start: Because the motor must be started/stopped by three entities (operator, box prox switch, and level full switch), I found it helpful to add a "System Run" control (O:2/2) that is on a separate rung and output from the conveyor motor starter output. I did look ahead to see what was coming up next, and this method made adding the 3-position selector switch in Exercise 3 much easier for me. As usual there are many different ways to do the job, and the secret is to find one that works for you.

I find it useful to insert the Outputs first (5 rungs in this case) and then use them for a simple outline of the problem. All that is left is to figure out what is the simplest arrangement of various parallel and series inputs needed to energize the outputs.