I'm not sure where to start. programming a valve contoller

[mikejeffers]

Hi,
I'm am completely new to PLC's. I am building a shuttle table/clamp for a drill press. We are drilling several thousand pieces of 3/4" cpvc pipe. The holes go pependicular to the pipe at regular intervals. Some pipe will have the holes spaced at 1", while others will have them spaced at 1.5" or more. I have a stationary Vee block (vise)with a pnuematic clamp to hold the pipe on one side of the drill bit. On the other side I have a pnuematic sliding table with a vee block (vise) mounted on it and with a pnuematic clamp on it also. There are adjustable hard stops on the sliding table. I have an SMC SQ1131NY-5-C4-Q valve controller. This is how I would like the sequence to go.
To start with, sliding vise is foward and and both vises are unclamped.

1. Operator loads pipe into both vises.
2. Operator pushes a start button activating both clamps to lock part.
3. operator drills a hole.
4. operator pushes start button again.
5. Sliding vise opens.
6. Sliding vise moves back to mechanical stop.
7. Sliding vise clamps.
8. Statinary vise unclamps.
9. Sliding vise moves foward to mechanical stop at start position.
10. Stationary vise clamps.
11. Go to operation #3 and repeat until part is finished.

At this point, there will be no feedback to the plc from the aparatus, which is fine. Eventually, we will set up a completely automatic cycle.
My valve controller has a 25 pin D connector on it.
The solonoids operate on 5v input.
I have never dealt with PLC's before and really have no idea where to start. I thought about using an extra computer to operate the valve controller, but I was told that even though the computer could put out 5v, that there would not be enough current to operate the solonoids.
I am not stuck on using this valve controller, it's just one that was available cheap.
Any suggestions would help me greatly.
Thanks
Mike

 

[itsmoked]

First suggestion would be to get a local geek to help you. Otherwise, you are going to spend a huge amount of time tinkering, and learning.

Second: There are companies that can help you with this stuff. Applied Industrial Technologies is a nation wide company that sells everything imaginable for doing this type of stuff. Often their sales guys can come out, look at your project, show you what parts they can provide, and how they're applied. You end up getting a few items you'd need anyway, and a bunch of on-the-spot technical advise for free, as they just want to sell hardware. They often know the right local guy to point you to if you're interested.

Otherwise you need a small PLC like, my cheap perennial favorite, TECO. Use a 'relay version' so your various power aspects don't matter for it's outputs. You need a 5VDC power supply that's up to the task. An appropriate enclosure to fit it all in. Various switches. Etc.

BTW: Why don't you just use an automatic drill? You can get really nice ones cheaply, used. I just saw two of them on a pallet that were surplus and had never been used.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[mikejeffers]

I really don't mind the learning aspect of it. It is nothing that has to be done right now. I enjoy tinkering with this stuff. I have a machine shop and we have machining centers to do these parts, but the pipes are about 10ft long, and I only have a 40" stroke. An automatic drill? That won't position the parts, will it? Eventually, if this job continues, we will make it completely automatic.
I will look into Applied Industrial Technologies website and see what kind of guidance I can get there too.
I'll also look into TECO. Do you know any PLC "books for dummies"?

 

[itsmoked]

Hi mikejeffers.

Look here and download the users manual. Look at it and see if it makes sense to you. If it does then the best bet is to just get one and mess with it. Otherwise PLC books will teach you stuff but you may have difficulty translating it to any particular PLC you'd get.

http://www.factorymation.com/s.nl/sc.2/category.22/.f

Keith Cress
kcress -

http://www.flaminsystems.com

 

[mikejeffers]

Ok, I have the plr, power supply, etc.
I bought the TECO SG2-20HR-D

http://www.factorymation.com/s.nl/sc.2/category.22/.f

I have been trying my hand at the logic. I guess I'm not very logical...
I'm using the fbd programming. (function block programming) because it seemed easier to understand than ladder diagrams.
If you are familiar with fbd programming, then I would appreciate some help.
Here is the scenario:
(no feedback to the plc other than operator start button)
I have 3 solonoids, all closed to start off.

operator input (start cycle)
Open solonoid 1
timer 2 seconds
open solonoid 2
timer 5 seconds
close solonoid 1
timer 2 seconds
open solonoid 3
timer 2 seconds
close solonoid 2
timer 5 seconds
close solonoid 3
end
I feel like I've been learing quite a bit playing with this, but I'm getting confused.
Thanks
Mike

 

[controlsdude]

Usually if you buy someones plc they can usually have their applications engineer help you. Otherwise its best have some outside plc guy design the controls and do a startup of your system.

You can be amazed at the amount of time that you can do spinning your wheels trying to learn the ends and outs of this system your trying to do by yourself.

I think the question you have to ask is it worth it do it yourself or cheaper to have a professional perform the work to a standard that you can live with and it perform reliably and at a rate that you can make money on.

 

[itsmoked]

Whoa, whoa, nelly. Start a bit slower.

Just get this to work:

operator input (start cycle)
activate solenoid 1
timer 2 seconds
de-activate solenoid 1
end

Recognize that the little blocks in the display mean the relays are closed or the inputs are active. This is very useful as they are basically idiot lights ready made. You actually don't even need the solenoids to do this.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[mikejeffers]

itsmoked,
Are you talking about ladder programming or by the FBD method?
I have not yet even begun to understand ladder logic, however in the FBD method, I have made some progress. I have not been able to figure how to tell it it's the end. Also I used a XOR block before the first solonoid, then the solonoid, then the timer, and back to the xor block.
Sorry for my terminology.
I do appreciate your help.
I'm still plugging away.
I have the solonoid positions(open or closed) all laid out on paper in the proper sequence. If you have used the FBD software from TECO, I can send you a copy of what I have so far.
Thanks
Mike
P.S. We are closing up shop tomorrow to go the IMTS show in Chicago (Friday). I'm really looking foward to seeing all the new stuff. I'm sure there will be some PLC gurus there.

 

[itsmoked]

Nope I'm not talking about the FBD method. I've never used it so I'm not sure how much help I can provide there. I always went for the ladder logic.

There is actually no 'end time'. The PLC starts at the top/front and steps down thru your logic. It gets to the bottom and starts over. Scratch my 'end' comment. Sorry to confuse you.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[roydm]

There are a thousand different ways of doing this task
One I favour is based on a counter e.g. Step 0 thru 6

Step SV1 SV2 SV3
0 - - - Wait for Operator to push button, Increment Counter
1 x - - Start Timer 1, when done Increment Counter
2 x x - Start Timer 2 " " " "
3 - x - Start Timer 3 " " " "
4 - x x Start Timer 4 " " " "
5 - - x Start Timer 5 " " " "
6 Reset counter
Then do some simple OR logic
SV1 = 1 OR 2
SV2 = 2 OR 3 OR 4
SV3 = 4 OR 5
The counter also gives you an indication of where you are in the sequence and can be used to animate text on a graphic display. It also allows you to expand easily.
Everyone has their own way of doing it, There's no right or wrong way and your method may be dictated by the TECO PLC.
Remember Document, Document, Document, if someone comes along behind you and can't understand your code, it's bad!

Have Fun
Roy