Learning by Doing

ArikBY said:

I can think about 3 options to solve the problem you mention:

1.Creep must to happen after running in high speed.

2.insert Auto run coil in NC to the counter reset.I am not sure it would help but it is the easy way.

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Not sure what you mean by these two, Arik.

3.put a rung with a compare to ignore the counting from the other direction.

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I tried something like this, but with no success. I used a CMPD function to reset if the encoder count was less than zero. I'm not sure what's happening exactly, but when the encoder count drops below zero, the program is unable to interpret the resultant number logically -- at least the way I've got it set up right now.

I'm thinking that some form of Eric's suggestion above (post #601) would be the most workable solution, and that's the direction I'm heading right now.

Paula

Paula,

A quick solution to that is open the shear during the feed and to cut the after it is detected coming out of the jaw. You'll lose a little stock on the feed but who cares?

maybe

Paula,
For some reason I can`t get the last version to unzip just get 1 file. But in the first version in when the cnts are = in rung 21
for .004 seconds you cut in rung 14. I don`t see where you ever stop the drive? If this is correct you might try turning off while you are cutting. If you happened to be creeping in rev. when the cnts or = maybe here`s where your getting the coast?
I maybe in LEFT FIELD it wouldn`t be the first time.

:site:

If not do like Eric said and cut at 10 or 100 and not 0

Re: maybe

Thomas Sullens said:

For some reason I can`t get the last version to unzip just get 1 file.

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That's entirely possible, Tom. I'll look into it, and try re-posting it if necessary.

But in the first version in when the cnts are = in rung 21
for .004 seconds you cut in rung 14. I don`t see where you ever stop the drive?

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The drive stops moving forward when the conditional in rung 18 goes false... in other words, when the encoder count is no longer less than the preset (desired length). But note that I abandoned the "=" method in favor of a multiple-pulse stopping range. (Which you can see in the updated program, that is if I can manage to get it zipped properly! )

If not, do like Eric said and cut at 10 or 100 and not 0

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Good advice, and already done. I used 10 encoder pulses, since that seemed ample. It solved the problem nicely. Just like adding the same number to both sides of an equation, it didn't affect the regular operation of the program in any way. However, I did have to subtract 10 pulses from the count that is converted to inches for monitoring the "Current Length" on the EZ-Text. So, though the Current Count "zeros out" at 10 pulses, the indicated length that the operator sees always goes to zero.

Paula


[BTW, it's been a loooong day, I need to get to bed! ]

So, Paula, give us an Update on the project!!

I am sure that you remembered, in your final version, to remove those "SP1" contacts on Rung 2 of your program, and put in the actual Encoder Inputs instead??

Also, on the program Rung 1 Comment lines, this is a good place to add your Company Name and contact information. Any programmer or owner making future changes may need to get in touch with you.

Hi guys,

Lancie1 said:

So, Paula, give us an Update on the project!!

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Your timing is impeccable, as I was just getting ready to fish out this thread for an update!

My machine builder finshed assembling as much of the machine as they could, with what they had. So, Don stopped by here yesterday to pickup the panel, and the rest of the components. They will finish assembling the machine and deliver it, probably in the next week or so. I will do the final wiring of the panel at the customer's plant (motor, encoder, prox. switches, etc.), and then we'll be ready for some trials. I'll be sure to let everyone here know how it turns out.

I am sure that you remembered, in your final version, to remove those "SP1" contacts on Rung 2 of your program, and put in the actual Encoder Inputs instead??

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Come again? I wasn't aware that I was supposed to. The examples in the manual show these inputs as SP contacts when using HSIO counting mode. Perhaps I'm misunderstanding?

Also, on the program Rung 1 Comment lines, this is a good place to add your Company Name and contact information.

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Good idea, thanks!

Paula

Paula,

SP1 is always on. It's commonly used to jump another contact or initate logic that will need to be done on all scans. It wont hurt or help your code in the manner that it's written into it. If you were reseting the encoder counter only to zero then you would only have SP1 contacts on the 1st two rungs of the counter instruction, and the "zero" contact on the bottom rung. It'll be a little cleaner to delete C10 or SP1 on the top two rungs.

Now However. if your intending to change the encoder count to anything other then Zero, you will need to disable the top rung and enable the 2nd rung to do this. In you case you have SP1 turning on C10 in Subroutine K2. So go ahead and delete all SP1s from the counter instruction rung so you wont be confused by this at some later time...5 or 6 years from now.

Additionally. Your program is commented very well. In fact it's the best documented code I've ever seen. However a quick discription and date etc is a good idea to place at the top of the program. Just remember none of you comments or lables etc.. are going into the PLC. If you set your options for no lables..you'll get the idea as to what's going to be stored in the PLC...nothing but the raw code. All comments, lables, etc.. are only kept on disk.

I cant wait to see a short video clip of this thing in action. That would be the coup degras since I cant be there. Think about that. It'll aslo make for a good training video for future operators.

Later.. Mike

BTW, open your ladder view, click on file -> properties, and you cand add some documentation there also.

Something like this...

elevmike said:

Something like this...

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I think I used to work there...

That is something I have always wondered..

What are nuclear reactors controlled with?? Gotta be DCS.

How cool would it be to write a program for a nuclear power plant!

Anyone have any insider info? Tripple redundant processors?

Inquiring minds want to know..

Anyone have any insider info? Tripple redundant processors?

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Only time I ever met a triple redundant processor system was a triple Kent K90 system at ICI's H-acid (base material for dyestuffs) plant somewhere in Scotland, near Ayr if I remember rightly. It shared a site with Nobel Dynamite complete with earth ramparts all round to deflect the blast upwards - wouldn't have wanted to live in one of the houses immediately outside though! I guess with Hydrogen in an exothermic reaction at 600 Bar you do need to take some precautions!

elevmike said:

...comments or lables etc... ...be the coup degras...

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Simply amazing, Mike. You misspell 'labels', yet have no trouble with 'coup de gras'?...

beerchug

-Eric

It's not what you think.

Jnelson said:

What are nuclear reactors controlled with?? Gotta be DCS.

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No, it don't gotta.

Once, I delivered a PDP-11 to a nuke plant. They used their backup and needed a "new" backup. This was about 10 years ago.

About 5 years ago, for Y2K, I upgraded a DMACS system to Fix32, which was controlled by a Symax PLC (The PLC was staying).

Now I can't say that it was the REACTOR that these systems were controlling, but the plants are not as modern as you would think.

The nuclear industry is worse than pharmaceuticals - one a system is validated - IT STAYS. And considering that there haven't been any new plants built since about '85 - well, you get the idea.

I hope that everyone sleeps soundly tonight, knowing that they are being protected by 1980's technology.

That's the trouble with this business - you get to know too much about how things are made. Laws and sausage.

Nuclear plant control

There are several Nuke plants here in South Carolina, the main control system is a circa 1984-85 DCS system from Foxboro called SPECTRUM. The Spectrum line was discontinued by Foxboro in the early 90's, but they still sell new systems to the Nuke industry because it's the only Foxboro product line that was ever "certified". Most of the GE plants use a GE DCS system of the same vintage, there may be others, Honeywell comes to mind. I've spoken to the Foxboro rep about this a couple of times, according to him, the major hurdle for certification is the earth quake testing.

Out side of the "main" system, more modern equipment is used: PLC's, other DCS's, etc...