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Lower-cost alternative to Automation Direct PLC

The Dude

Hot Rolled
Joined
Oct 19, 2010
Location
Portland, OR
I'm helping a customer implement mask sewing/processing and came up with a method to "weld" the polypropolene together using cheap soldering irons. I can "semi-automate" the process with just a foot valve and air cylinder but would like to take it a step further to at least control the timing. This would change the foot valve to a switch, activate a solenoid valve for 1-2 seconds to extend the cylinder, retract it, then shine a light after about 2 seconds to tell the operator they can pull the part (keep light on for a few seconds, then turn it off). About as "wash/rinse/repeat" as you can get.

Since it's for mask production, at this point it's only going on for maybe 7-8 weeks. Further automation/closed-loop control isn't likely justifiable (cylinder prox swtiches, temp controls, etc.). My knowledge is best suited to AD D05 series PLC which you can buy for about $90-100 but it's much more capable that what's needed.

Here's the minimum specs:
Ideally l20 VAC, 12 or 24 VDC power.
2 outputs. Could use another one just to indicate the power is on.
1 input for the cycle switch.
Cheap/free ladder logic software (that's the only control language I know, probably take to long to learn a new language unless I can find someone local to program it).

I did find a cheap "Module FX1N-14MT-2" PLC (open board, no case) on eBay, looks like it would work. Uses Misubishi GX Developer Or GX Works2 software that I could likely learn pretty quick.

Just wondering if anyone has any suggestions. I investigated the PI a year ago for another application, main concern is learning C++ or whatever the language was. Do you think there's someone who'd be willing to write a program for it?

We'll likely be building at least 10 of these, up to 15-20 depending on final cycle time & demand. Not "super urgent", if I can't find anything cheap, quick to buy and easy to implement, I'll keep it with just a foot valve.

Thanks,
The Dude
 
Get a Click PLC and be done with it. You're already familiar with AD's software and finding anything cheaper than $70 on ebay will take more effort in research of the product and its software to figure out if it will work. How much is your time worth? If it takes 45 minutes for one ebay listing it might be worth it. If you buy that one listing off of ebay, can you find 10-20 more of them for the same price or will you need to do 45 min more research per unit and end up with every unit being a Frankenstien's monster? If the customer really wants to complain over the choice of a cheap PLC, they can't afford the project.
 
Buy one PLC with enough I/O ports and timer resources and have it run all 10 or 20 assembly stations.

Build your own three- or four-step ladder with relays. Gotta say that a (new) Omron time delay relay costs a pretty good fraction of a Click PLC, though.
 
About the only thing I've seen cheaper than the small PLC's from Automation Direct are cocktail napkins from Trader Joe's. What's your budget for this project...$20.00 dollars?:o

Stuart
 
Yeah, my initial reaction to the thread title was "Automation Direct is the low-cost option." But maybe he doesn't need to buy a separate PLC for every station.
 
It doesn't get much cheaper than a click PLC, and it will be there in two days.

I've also heard good things about Velocio. they start at $50, but you'll need a separate power supply, and if you already have 24V for the pneumatics, it's not cheaper than a click.
 
I have used Velocio PLC's for a couple of very similar applications. They are inexpensive and - in my experience - reliable. Ladder writing software is free and simple to use and their support is very responsive.
 
AD supports the 305 and 405 series for at least 30 years too. 205s are still current after 25 years. Stop trying to do cheap and focus on making the process better and make money.
 
Buy one PLC with enough I/O ports and timer resources and have it run all 10 or 20 assembly stations.

Build your own three- or four-step ladder with relays. Gotta say that a (new) Omron time delay relay costs a pretty good fraction of a Click PLC, though.

That's my decision right there. If a single timer is required then you might as well go the PLC route.

There are old school mechanical leakdown timing relays but why bother?
 
Great idea, it will spare us some bucks! I will try it and hopefully it will work good.
 
It'll work, right up to the point where the customer says "This is great! Now that I see how it works we just need to add...". You are supposed to be helping the customer not hindering him.
 
It'll work, right up to the point where the customer says "This is great! Now that I see how it works we just need to add...". You are supposed to be helping the customer not hindering him.
It's called a "change of scope", meaning you buy another dirt cheap PLC and double the price of the machine.
 








 
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