Interested in Approx Costs

Hello, I work in a water factory where our cup machine died. The equipment we are using is:

MicroLogic 1000 (1761-L32BWA)

Instead of calling in outside help, my boss wants us to be able to handle programming issues in-house. So I'm taking a crash couse in PLC programming and Rockwell software and Allen-Bradley equipment.

Here's our problem in a nutshell:
The circut that controls our heat seal has gone awry. When the machine is turned on there is a constant 111.4acv leaving the O port. This is keeping the pneumatic acutator open and causing the machine to chew up sheer-pins. Also, the light is OFF for the port in question.

My Questions:
What can I report to my boss on costs for interface software?
What hardware is best? (Laptop, handheld?)
Is the Micrologic 1000 toast?
If so, how much can I expect a replacement to run me?
Will it be hard to reprogram it when I have access to the current program as well as the ladder table printed out?

Thanks in advance and I appreciate the time for reading this.

Maetrix

Meatrix,

What drives the O port? What do you mean by O port? Are you talking about an output?

If you want to get serious, the laptop running RS500 is the best for the ML line. You'll be able view the entire program, comment it, get online & troubleshoot it etc.

I would do a little more investigation into the problem now before I got too worked up about replacing it. If you describe it well, I'm sure we can help point you in the right direction.

The L32-BWA has 20 DC inputs 12 and relay ouputs. Crocop is right, the problem is not necessarily with the ML, it may be elsewhere in the machinery.

However, since the light for the output is off, then the PLC is not turning it on. The relays in the ML are pretty light duty. It is entirely possilbe that the relay has welded closed. You can check this with a multimeter. Turn off the power to the machine and disconnect the wires to the output and its associated common. If you have continuity, then the relay contacts are welded closed. The ML is a throw-away unit, so if that is the case, you just replace it. If you have an unused output you can modify the program and change the function to that output. If you are operating a 24 volt pneumatic valve, the solenoid is probably something on the order of 25-30 watts, which is on the upper edge for those outputs. If that is the case you should use an interposing relay that can handle the power to operate the valve.

I think that the L32 is going to be around $300 for the PLC (not too bad) but the RSLogix 500 programming software is going to be between $500 and $1000 depending on which package you get. You will also need a programming cable (about $40) to talk to the ML.

Go to www.ab.com and on the left hand side of the page there is a link to the literature library. There you can find all the manuals on the ML PLC.

I agree with CroCop about the laptop. In this day and age the handheld is not workable anymore unless you are refering to a pocket PC. In that case I have no experience with one for PLC's.

What is your bosses title or position?

Does he have a clue about anything going on?

What is your role or function? Maintenance?

Has anybody called the local answer man? The Allen Bradley sales rep?

CroCop said:

Meatrix,
What drives the O port? What do you mean by O port? Are you talking about an output?

Click to expand...

I appologize for the vagueness. I isolated the problem on the phone with our supplier. He told me to use the multimeter to see if the wire is hot. (it was and it shouldn't have been)

This has happened before, and the output for the heat seal is now on line O/5 (as opposed to the original o/7)

The two problems I face tomorrow are 1. Is there a port left to re-wire the solinoid, and 2. What will it take for me to reprogram it to the new address.

Though my background is in computers, PLC programming is new to me.

Here is a schematic of my Micrologic 1000 with the offending circuit. I hope it clears things up.

thnx again.
--Maetrix--

Thank you for the excellent advice. If we have to toss the unit, are you suggesting I upgrade to a "L32-BWA" and not get another ML1000?

Will that require a complete rewire & reprogramming? (That would be beyond my abilities at the moment)

And he would rather buy the software once - the money is already spent when you consider the cost of a technician - and have the ability to tweak the unit at will.

For those interested, it for a 4oz Cup Machine with a potential output of 70 cups per min. Our goal is to maintain a functionality of 90%. Something that's been one challange after another.

Maetrix said:

If we have to toss the unit, are you suggesting I upgrade to a "L32-BWA" and not get another ML1000?

Click to expand...

That's not an upgrade, it's simple an exact replacement. Upload the existing program, label wires (<- IMPORTANT!) and disconnect old unit. Install and reconnect wires on replacement unit, and download program.

Do you need the software and cable? That would probably be beneficial in the long run, but right now you need to get this machine fixed, right? What happens if you make a mistake and lose the program during the learning process?...

Here's what I'd do at this point. You are going to be buying a new ML1000 (plus perhaps a spare to learn on), and probably software and a cable. Ask your AB rep. if he'd be willing to transfer the program for you to get you running again. It should take him no more than 5 minutes total to do this. You get back running, and he gets a sale. Sounds like a decent trade to me... :nodi:



-Eric

I think the idea by Alaric of installing a relay is your best bet for longer uptime. Especially if this has been a problem in the past and it sounds like it has. Since you said the output had been moved from its original location.

Eric's suggestion sounds like the quickest way to get your equipment up and running. If your AB rep has one on the shelf and is willing to do it.

Another suggestion that might eliminate the problem and get you up just as fast if time is a BIG concern is to move the output to another good output (better check it first, it could have happened several times in the past and been moved so you may be limited) and have your PLC contractor come out and change the program. I still think Alaric's adea of a external relay to switch the load will save you trouble in the future. I modified your jpg file to show the relay connected to the new output. The blue line is current the red line is the new output. Basicly you just put the relay in the position of the solinoid and then run power for the solinoid thru the other side of the relay. This should stop the welding of contacts and if it does not a relay is ALOT cheaper than a PLC.

For some reason i (i know i am doing something wrong) can not get the jpg file to upload or i sent it to the wrong place. Sorry