PLC system components

[mwalrath]

Hello!

Currently trying to determine the best way to control a motor doing a simple start-reverse-stop operation. The motor speed would need to be easily changed if necessary as it would be determining feed rate of the machine. Ideally this would be an operation that once fine tuned, could run one cycle with the push of a button. With the research I've been doing it seems using a PLC to control the operation would give me the most flexibility and reliability.

I am hoping someone here can help give me an idea of all the components necessary to make something like this happen, and maybe an idea of how it would all be set up.

Motor would be servo type operating a ball screw slide table feeding a hole saw through a thin walled tube. Any sensors that were used in table positioning would need to be resistant to coolant or cutting oil, so ideally I would be able to program the motor to run for a period of time with the PLC without the use of table position switches/sensors. Should also mention that cost is a very big concern, but more concerned with understanding at the moment.

Thanks for the help!

[underthetire]

Building one myself right now. It's a rotary application, but same thing. I'm using a siemens logo smart relay. Not sure how good it works yet, just got the programming done in the relay. Even with this, still using a small dc servo amp and servo with encoder. I'm sure you can do it with steppers easier and still use the logo module, but we need smooth travel, steppers are a little jittery. The logos are my go to unit, I always have them sitting around, they are less than 150 for ones withna display.

[mike_Kilroy]

I just sent this to someone else but it seems like it would apply for your application also. Our Kollmorgen servo drives today have full position controls built in. Software to command them is free and easy to use.

So as I said in earlier post on your topic, if you are willing to just use speed pot and run to end of travel limit sw and stop then push another button to go back you can do this with just about any servo drive today. but with postiion control built in there are "motion tasks" you can program to go from point a to point b and stop repeatably each time. speed can be preprogrammed or from a pot to make it adjustable. you can store 128 predefined moves and then call them from inputs. or you can send a serial command to the drives to make the move; on the cd series drive, you send "MA 1200 1000" for instance and it will move 1200 counts or if scaled say 1200mm or 1.2" at a speed of 1000rpm or 1000IPM or whatever. So if you have a computer on anyway doing your stuff you just open the Motionlink or drive.exe window and tell the servo what to do. no plc required. Or program motion tasks and then push a button to go from point a to b, wait until another ubtton pushed or time delay say of 5 sec then return to point a or go to point c etc. all in the drive.

so if you want to do it yourself without programing, check out our CD drive with Motionlink or S300 drive with drivve.exe or AKD drive with workbench free software. just click on:

http://kollmorgen.com/website/com/en...akd_drives.php

http://kollmorgen.com/website/com/en...rives/s300.php

http://kollmorgen.com/website/com/en...d_series_5.php

price of motor depends on size but sounds like 3" square maybe? about $ 600. drive about $ 1000 to run on 120v or 230v 1 or 3ph. premade cables available too.

I'll send a PM with contact info if you want to discuss these options.

[mwalrath]

underthetire, thanks for the heads up on that plc unit. That will be almost exactly what I will be looking for when I build. Reasonably priced as well! Are you using a brushed DC motor with your system? The slow speed reliability of a brushed DC motor would be ideal for my application while being within my price range as well. I read somewhere that brushless AC or DC motors were more reliable and widely used in applications involving a lot of starting and stopping. I'm assuming this is due to heat build up. Should I be worried about reliability of a brushed motor in this application? I'm also curious if you plan on using positioning sensors to control the motor movement, or if you are programming run times into the plc.

kilroy, very good looking system. In fact it looks ideal to be able to control simplistic control from the drive without needing a plc, since that's all I need to do. The cost is extremely prohibitive though, as the cost of the drive is twice what my budget will be for the automation.

Thanks for the replies

[mike_Kilroy]

That's why I put the ballpark price of the full blown drive in the message - I thought it might be too expensive for this job! Thanks for the feedback!

[underthetire]

underthetire, thanks for the heads up on that plc unit. That will be almost exactly what I will be looking for when I build. Reasonably priced as well! Are you using a brushed DC motor with your system? The slow speed reliability of a brushed DC motor would be ideal for my application while being within my price range as well. I read somewhere that brushless AC or DC motors were more reliable and widely used in applications involving a lot of starting and stopping. I'm assuming this is due to heat build up. Should I be worried about reliability of a brushed motor in this application? I'm also curious if you plan on using positioning sensors to control the motor movement, or if you are programming run times into the plc.

kilroy, very good looking system. In fact it looks ideal to be able to control simplistic control from the drive without needing a plc, since that's all I need to do. The cost is extremely prohibitive though, as the cost of the drive is twice what my budget will be for the automation.

Thanks for the replies

First shot will be a brushed DC motor with encoder. It's already there. I do prefer the brushless stuff, i have used the Bodine all in one for other applications with great success, but i'm not sure if the fake position count output is going to work yet. I know the encoder will probably work. The bodine set up went with prox switches, it's been running for 3 years with no downtime yet. I usually have a much larger budget than your working with though. I'm interested in the Kollmorgen stuff. I've called before and never got a straight answer, just like the quicksilver stuff I bough before. The kollmorgen is still way under my budget, so no problem there.

[underthetire]

Oh, and here are the different LOGO units, and you can download demo software to play. The starter kit from our local rep was 150.00, with all the manuals, logo module, cable, screwdrivers, and tool box.