Overall my original post on buying surplus industrial automation equipment is still on the mark.  I won’t repeat it again this year; instead, here are some comments based on 3 years of monitoring eBay and adding to my collection.

In Silicon Valley there are only two decent electronic surplus stores: Excess Solutions and Advanced Component Electronics.  There hasn’t been a good local source for mechanical surplus since Triangle Research closed its doors.

On the web, PLCCenter has a great selection, is great for getting an idea of what stuff costs new, but has premium pricing (except for some on-sale items).

eBay is still the best source, but you need to be patient and know what equipment is worth.  In general, I’m willing to pay 10-20% of the original cost, but many eBay sellers try to get 50%, and a few even ask for more than 100%.  In general, “Buy It Now” means “I think my junk is worth a lot”.  Availability is very spotty; some months there’s a lot of interesting stuff, some months there is nothing.

Also, be sure to check condition and return policies.  Many eBay sellers do not have the ability, equipment, or inclination to test industrial equipment, so if it says “as-is”, don’t pay a lot.  Most of the industrial equipment I’ve bought has worked, but I’ve bought a number of AMC and Elmo drives that don’t want to communicate (since the lights blink, I haven’t given up yet; I haven’t had time for extensive troubleshooting).

Don’t forget new equipment; many vendors (including Siemens and Panasonic) have offered somewhat-affordable starter packages including equipment and software (e.g. PLC and programming software).  Some new PLCs are so inexpensive you don’t even need a starter kit: for example, Automation Direct’s Click PLC starts at $69 and the software is free.

Comments on specific equipment:

• Last time I checked, it appears the Cognex Insight smart camera software is now a free download (after registration).  But I recommend verifying this before buying an Insight camera (which will probably cost >$100).
• DVT smart cameras are still often available on eBay, with pricing ranging from $50 (Legend 510 bought at the right time) to $500 or more (color model such as the 542C).
• Galil motion controllers availability is good, with a wide range of pricing (there are many unrealistic sellers).  USB and Ethernet models are more expensive, although if you’re lucky you can buy one for under $250.
• CANOpen interfaces from Kvaser and Ixxat are frequently available for $50-$150.  I’d recommend getting a used Kvaser or Ixxat instead of a new interface from someone else (which will be at least $100 anyway) because they have the best software support.
• Copley CANOpen servo drives are available fairly often; a reasonable price for an Accelnet is $50-$120; the Xenus is more expensive (>$150).  The Accelnets are my favorite servo drive.  I avoid the older models (800-xxxx)  because I can’t find any documentation for them.
• Elmo CANOpen servo drives are frequently available.
• Ethernet Powerlink drives and EtherCAT drives are occasionally available , but the prices typically aren’t reasonable.
• MEI controllers are often available, at a wide price range, but I’ve never seen the software included.  If you don’t have MEI software, don’t buy the board.
• Panasonic PLC’s are frequently available, but in general I think the asking prices are too high.  At least Panasonic now provides a code-sized limited (but still quite useful) free version of FPWin Pro 6.
• Opto 22 I/O controllers, such as the B3000 and LCSX, are frequently available, often at reasonable prices ($50 and up).  Opto 22 PACs are rare and expensive, especially the current models.  Opto 22 I/O module availability is good.
• Wago 750 and Beckhoff K-bus availability is good, and, if you’re patient, you can get them at a reasonable price.
  • The most popular couplers are for DeviceNet, CANOpen ($25-$75), Profibus, and Ethernet (>$100 for 750-842); I’ve also seen Interbus, serial, and EtherCAT.
  • Digital input and output modules are the most common, and cheapest.
  • Analog modules are less common, and more expensive, but if you’re patient, you can get one for <$50.
  • Specialty modules, such as encoder interfaces and stepper drivers, are the least common and most expensive.

Let’s say you want to learnplay with real industrial automation equipment in your garage (or living room, if you’re single), not toys like the Lego Mindstorm. After all, learning is fun, and it’s cheaper than taking college classes (that’s what I tell my wife). Unless you’re rich, buying surplus is the way to go.

In the past, if you lived in the right area you could visit the local surplus store. Silicon Valley used to have a lot, but most of them disappeared during or after the dot-bomb bubble and subsequent crash. Still, there are a few places left, such as Triangle Machinery (the best place for mechanical stuff) and Excess Solutions. DeAnza College hosts the monthly Electronics Flea Market.

Now the overall situation is better because of on-line sites such as eBay (still the best overall), craigslist (worth checking, but probably best for test equipment), DoveBid (typically best for test equipment or large industrial equipment), and PlcCenter.

Mechanical items such as stages and motors are pretty easy to use. But when looking for equipment such as motion controllers or PLC’s, you need to consider:

1. What software does the equipment require? The best case is when the equipment comes with software or you can download the software from the manufacturer’s web site. Next best is when the necessary software is at least somewhat reasonably priced (so you can afford to buy it (e.g. some PLC software)). The worse case is copy protected software (Allen-Bradley, Cognex, and many others).
2. Does it come with documentation or can you download it?
3. Are the necessary accessories readily available? If it’s a rack, backplane, or snap-together system (many PLCs, Opto 22, Beckhoff, Wago, etc), you have to be able to get all the required pieces (backplane, power supply, CPU, I/O modules, etc). For a motion controller, are the break out boards and cables readily available?
4. What are the power requirements? Many servo drives are 3 phase 240V or 480V.
5. Is it readily available surplus? Important if you want to expand later.
6. Have you used it before? Familiarity obviously helps.

My recommended list:

• Galil motion controllers. Yeah, the two letter commands are stone age. But Galil controllers are readily available on eBay, you can download all the essential software and documentation, the connectors and breakout boards are readily available (but if you buy them new they might cost more than the controller cost on eBay!), and it’s easy to get started.
• Opto 22 PACs. I haven’t used them, but software for the SNAP controllers is free, and they’re often available on eBay.
• DVT smart cameras. Software for the older models is free, and they’re often available on eBay. I’ve heard that software for newer (after Cognex bought DVT) models is protected.

CANOpen is a mixed story. CANOpen availability is good (AMC DX15C08 Digiflex drives are readily available at great prices, other drives such as Copley Accelnet, Copley Stepnet, Baldor MintDrive, and Kollmorgen Servo Star are occasionally for sale, and I/O controller such as Wago 751 series are sometimes seen). However, you will need a CANOpen interface (I recommend Acacetus VCCM or Peak USB-CAN because they’re supported by CanFestival). Getting started with CANOpen is still a lot of work; starting from no knowledge, it takes much more effort than getting a Galil system up and running.

• Plenty of others, including many I haven’t heard of. Other possible examples include Logosol, Animatics SmartMotor (also stone age commands, but…), and JR Kerr’s PIC-Servo boards (quirky, but affordably priced new).

Not recommended:

• MEI motion controller without software – nice boards (the XMP looks really nice), and occasionally seen on eBay, but IIRC the software is $4900 for the older systems and $19,000 for the XMP.
• Cognex Insight smart cameras. Nice systems, often available on eBay – but every time you install the software you have to call Cognex to get a key for that particular PC.
• Most PLC’s, especially any you have not used, unless they come with programming software and the appropriate licensing (dongles, disks, etc). The “big name” vendors like Allen-Bradley tend to like nasty copy protection schemes – software keys that have to transferred via floppy disks are the worst, since they are so easily lost (and who has floppy drives anymore?) . At least hardware dongles are harder to lose.
• Anything you don’t know about or can’t find out about.

Some good sources for cables and breakout boards:

• L-Com
• Cables On Demand
• ASI

Sometimes it takes patience and multiple sources to put a working system together. I bought my Wago 751 series CANOpen controller from eBay, but I bought the I/O modules from PlcCenter (they were available at reasonables prices). I bought my Festo CPV-10 CANOpen control module from eBay about a year before I found the CPV-10 pneumatic manifold and valves available at a reasonable price.

Note: go here for my 2011 Update

Tony