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Best Industrial Equipment For The Garage: 2011 Update

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.

June 20, 2011   5 Comments

Applicom CANOpen Cards And Other Tidbits

I’ve been busy lately with a variety of tasks, including buying a car.  I’d enjoy car buying if I had a big budget and was looking at fun cars like a Mini Cooper S Convertible (my semi-practical dream car), but buying a used car for my wife is another matter.

But since it’s been too long since my last post, here are some quick notes:

  • The next post on the Eagle PCB and Alibre series is in progress
  • I recently picked up a Applicom DirectLink DRL-CNO-PCU CANOpen card.
    • Applicom is now part of Brad which is part of Molex.
    • Anyway, the DirectLink card is a PCI plug in card with a CAN connector (DB9F, first time I’ve seen that) and some sort of x86 processor.  The CANOpen stack is run on the DirectLink board; there’s no need to run a CANOpen stack on the PC side (e.g. CANFestival).
    • DirectLink cards are available for a variety of interfaces (e.g. DeviceNet, Profibus), and share a common API.  They’re meant to be used to interface fieldbuses with SCADA and soft PLC applications.
    • However, I noted that the CANOpen software does show support for DS402 (motion profile).
    • One nice plus is that the software will scan the network for CANOpen devices.  So if I have a CAN device with unknown ID and baud rate, I can just change the baud rate and then let the DirectLink card figure out the CANOpen ID.
    • I plan on writing more about this card, after I finish my current series.
  • I managed to get over to Maido Stationery, and pick up some more JDM pens and a 0.3mm Kuro Toga pencil, so I’ll be doing another pen post soon.

July 29, 2010   No Comments

Book Review: A Comprehensive Guide to Controller Area Network

A Comprehensive Guide to Controller Area Network by Wilfried Voss, Copperhill Media, 2008.

Summary: 8.0/10,  recommended reading if you are developing systems using CAN or higher level protocols such as CANOpen.

The Guide is an affordable (<$15) book on the low level details of the CAN protocol.  It covers in detail the different frame types (data, remote, error, and overload), network arbitration, error detection and recovery, and data transfer synchronization.

The Guide points out undefined or ambiguous areas in the official specifications (Bosch, ISO, CiA), including updates based on experience (such as the CiA’s recommendation not to use remote frames).   The book concentrates on the base CAN protocol; it does not cover higher level protocols (such as CANOpen) in any detail, nor does it describe the specifics of CAN controllers or transceivers.

The book is well written; I’m an automation software developer, not a low level embedded developer, but I was able to follow the explanations without any major problems — I’d say it was easier to read than many software development books.

If all you want to do is get a basic CANOpen control system running, then you can skip this book.  But if you to truly understand CAN and what it can do, then I highly recommend reading both this book and Embedded Networking with CAN and CANOpen. Here are some things I learned from the Guide:

  • How fast CAN really is  (data throughput, error recovery time, etc), including protocol overhead, for both standard and extended addressing.  Serial network protocols have a substantial overhead.
  • Termination resistors have be able to dissipate at least 220 mW.
  • Terminators should be at the network ends, not inside the CAN device.
  • The details of error counting and error frames.  I had been wondering what the Copley CMO library’s ErrorFrameCounter property really meant; now I know.
  • The meaning of the bit time segments  and how bit resynchronization works.  The Grid Connect (aka Acacetus) CAN-USB Light manual refers to the bit segments (sync_seg, prop_seg, phase_seg1, phase_seg2, SJW, etc) but didn’t explain them.  Now I understand bit segments.

The Guide‘s network topology recommendation (straight line topology with minimal stub lines with terminators at the ends) match what I already do.  I was happy to see the correct recommendation for shielded cables (connect the shield at one end only).

I do have some small nitpicks and suggestions for improvement:

  • The book is repetitive; the exact same explanations with the same diagrams appear multiple times, as do various notes and warnings.  I find this annoying when reading the book straight through; however, overall, it’s probably good — when using the book as a reference, I want relevant warnings in the section I’m using, not just in one place in the book.
  • The diagrams could be better explained; there is no key to explain the dark black lines (high line only means that field is always recessive; low line only means the field is always dominant; both high and low lines means field can be either depending on the message — maybe that’s obvious to hardware guys).
  • The diagrams could be clearer: a bit larger with more contrast.
  • OK, the book isn’t a comprehensive guide to CAN transceivers.  But I would have appreciated some warnings about common physical layer gotchas.

May 6, 2009   2 Comments

CANOpen Adapters

I am working on a series of CANOpen cable adapters.  For example, here is a model of a DB9 to dual RJ45  adapter:

CANOpen DB9/dual RJ45 adapter

CANOpen DB9/dual RJ45 adapter

I made sure it will work well with AMC DX15C08 Digiflex drives to convert the DX15C’s DB9M to two RJ45s.  The Phoenix header (in green) is for supplying power to the DX15C’s isolators.  Since I will probably make some more changes (for one, I don’t think there is room to screw the adapter’s DB9F to a DB9M), I am not posting the design files yet.

April 30, 2009   No Comments

Mixed CANOpen Connections (DB9/RJ45)

I have trac page up on connecting CANOpen devices with DB9M connectors to a RJ45 network.

December 9, 2008   No Comments

CANOpen Connections Using RJ45 connectors

I have a page up on my trac site about connecting CANOpen devices with RJ45 connectors, including RJ45 terminators and breakouts.

December 9, 2008   No Comments

A Trio of CAN Interfaces

Ixxat, Acacetus, and Peak CAN Interfaces

Ixxat, Acacetus, and Peak CAN Interfaces

I now have three CAN interfaces.  I plan on doing tests on all three to measure their performance.

The Acacetus (also sold by Grid Connect as the CAN USB Light) is the least expensive ($100).  It communicates via a virtual COM port.  So far I’ve used HyperTerm to communicate with it, which doesn’t work well (binary data isn’t intelligible, etc).  Using a serial library should work better.

The CAN and virtual COM port settings are accessed by resetting the device, and then going through a series of menus.  The CAN baud rate isn’t set directly; instead you set the various detailed parameters; fortunately, I found a handy table, but I much prefer Ixxat’s approach (pick the baud rate, and then tweak if you want).

So far, it works, but doesn’t seem in the same class as the Peak or Ixxat – it doesn’t feel as well built, and is more limited (e.g. can’t set baud rate remotely).  It only comes with driver software.

The Peak is a parallel port dongle; I much prefer a USB connection, but I didn’t pay for the Peak.  It has a keyboard pass-through connector to provide enough power.  It is sold in the US by Grid Connect and Phytec for $249.  The Peak USB to CAN is $279, but is worth the extra money.

The Peak interfaces come with PCAN Light driver, and PCANView which is a simple program to send and receive CAN messages.  The extra cost, advanced driver has some nice features, such as sharing a CAN interface among multiple applications.

Right now, the Peak is handy because I have PCANOpen Magic Lite for it (it was included with the CANOpenIA-XA kit I have), which provides some basic CANOpen functionality.  It has many restrictions; for example, it only supports CANOpen address 0x40 to 0x4F, so I had to remap my Copley drives to this address range.

The Ixxat USB-to-CAN compact is the most expensive ($335 from CAN Connection).  It comes with drivers and some helper programs, including one similar to PCANView, but does not include any CANOpen specific software.  I talked about it in my previous post.

Comment 8/24/2011: I now have a lot more CAN interfaces, including models from Kvaser (PCI and USB), esd electronics (PCI), and Applicom (PCI).  I really like both the Ixxat USB to CAN compact and Kvaser Leaf Light. 

October 25, 2008   No Comments

My Ixxat CAN Interface is Here

Ixxat Box

Ixxat Box

I recently received an impressive blue ESD safe box.  Inside was the  Ixxat USB-to-CAN compact interface which I had ordered from the CAN Connection store.

So why spend the money on the Ixxat when I already have two CAN interfaces?  Software support.  I decided I needed a CAN interface which is supported by the manufacturer’s setup and tuning software.

I like USB to CAN interfaces – I do not having to open up my computer to plug cards in (although I do wish USB connectors could lock – it’s very easy for them to become disconnected if I have to move my computer around).  I’d like an Ethernet to CAN interface even better, but the only semi-affordable ones I know of are the Anagate CAN interfaces (about $300-$450), which are only supported by CANFestival (but not by AMC, Copley, Elmo, etc).

Only Kvaser and Ixxat CAN interfaces are supported by all of the CANOpen servo drives I own (AMC, Copley, Elmo), so I decided to buy either a Ixxat USB-to-CAN compact or a Kvaser Leaf Light.  I decided to buy the Ixxat because:

  1. I like the Ixxat physical arrangement better (only the USB cable is permanently attached).
  2. Kvaser currently does not have a CANFestival driver, which is very important since I plan on using CANFestival.
  3. Faulhaber and Maxon support Ixxat but not Kvaser.
Ixxat USB to CAN compact

Ixxat USB to CAN compact

My Ixxat does have a quality feel to it, and unlike many CAN interfaces, does pack substantial processing power (a 24MHz Infineon C161 with 128K SRAM and 512K flash).  It is available with either a single RJ45 or single DB9M connector.  I choose the DB9M version since my other CAN interfaces use DB9M connectors.

Right now I am using the Ixxat with the Copley CMO COM library.  One quirk – Copley supports Ixxat in their CMO and CML libraries, but not in CME2 (Copley’s setup and tuning application).  Copley supports Kvaser in all three.

CME2 is needed to setup the drives.  The CAN baud rate has to be set from CME2, as well as the amplifier settings such as Hall sensor settings.  However, it’s easy to connect using the Copley’s serial port and a properly wired RJ12 to DB9F cable.

October 25, 2008   8 Comments

CANOpen Fun with M12 Connectors

Since I have been working on communicating with my Festo CPV10 valve manifold, I have learned a lot about M12 connectors and cordsets.

The Festo CPV-10-GE-CO-8 CANOpen valve terminal has a DS303-standard 5-pin M12 plug (male) connector. The second generation Festo valve terminal (CPV-10-GE-CO2-8) allows the choice of
DB9, M12, and terminal block. In my CANOpen research so far, the most common connectors are DB9, RJ45, M12 (for harsh environments), and terminal block (especially for I/O).

My preference is dual RJ45 connectors for normal environments, and dual M12 connectors for harsh environments. M12 connectors are typically IP67 rated, are available with 3, 4, 5, and 8 pins, can be shielded or unshielded, are quick to connect (unlike most DB9’s), and are vibration resistant. M12 connectors are used most often to connect sensors back to a controller, often via a concentrator or fieldbus box. Other uses include CANOpen (of course), DeviceNet, Profibus, and Banner light curtains.

Since nothing stays simple, there are a number of M12 variations. The ERNI catalog lists five polarizations: A,B,C,D, and P. The A or normal polarization is the most common, and is used by most sensors and CANOpen; the B (or reverse; used for Profibus) and D (used for Ethernet) polarizations are available, but not as common.

I looked at M12 connectors and cordsets from Phoenix, Binder USA, Lumberg, ifm efector, ERNI, Turck, Hirschmann and Tyco/AMP. It’s interesting to see what is available that could be used with CANOpen

Connector availability is good, with plenty of choices for PCB mount, free-hanging, and bulkhead mount in male, female, and right angle versions. Single-ended cordsets with a male straight, male right angle, female straight, or female right angle connector are common.

However, I only found Male/Female double ended cordsets; I have not found any Male/Male or  Female/Female cord sets. All the Tees I found had 1 male and 2 female connectors. I think this comes from M12 connectors use in sensors. Extension cables have to be M/F. A 1M/2F Tee splits one female connector into two female connectors, allowing two sensors to be wired to one connector (most sensor boxes use female connectors, and some do support two inputs to one connector).

This can work well for CANOpen systems, too. DS303 does not provide guidance on how to connect the whole system, but DS102 does for DB9 connectors. Applying the Interconnected Bus Line approach from DS102 works perfectly for M12 connectors: start off with a M12 female terminator, connected to M/F cable. The cables are connected together using a Tee (with 1 male, 2 female connectors) for devices with 1 male M12 connector (with one of the Tee’s female connectors connected directly to the device’s M12 male
connector or via a M/F stub line cord set), and connected directly to the device for devices with Male & Female M12 connectors. The bus ends with a M12 male terminator.

The parts required are available, except perhaps for the female terminator (but that can be made easily). However, compared to RJ45 cables, the cost is high. Using Allied Electronics pricing (8/17/08) for Phoenix, a male terminator (1507816) is $17.96, a CANOpen Tee (1507793) is $44.91, a Sensor/Actuator Tee (1683468) is $24.06, a CANOpen M/F 0.3m shielded cable (1518258) is $47.72, and a 0.3m M/F Sensor/Actuator cable (1519040) is $21.70, and a shielded 0.3m Sensor/Actuator cable (1500884) is $31.49. Long cables don’t cost
a lot more; for example, a 3m Sensor/Actuator M/F shielded cable (1500910) is $40.04. I’m not sure what the difference is between Phoenix’s recommended CANOpen cable and the “Sensor/Actuator” shielded cable, or between the “CANOpen” Tee and the “Sensor/Actuator” Tee.


August 18, 2008   No Comments

Finding Information on the Festo CPV-10-GE-CO-8

Comments 8/18/2011: It looks like Festo has changed their web site around.  So some of this information may not work, but since their search still sucks, I hope my basic approach is still useful.  I’ve used strike through to indicate links that no longer work.

I have a Festo CPV10-GE-CO-8 CANOpen valve terminal. Since I found it very hard to find the documentation for it, I am sharing how and where I found the information.

The Festo CPV series is a modular pneumatic valve system, consisting of a base, side panels, up to 8 valves, and a valve terminal top plate. The valve terminal can be directly wired to each valve solenoid, or it can be a fieldbus interface such as CANOpen, DeviceNet, ASI, or Profibus. The second generation valve terminals have an added “2” (so the new CANOpen valve terminal is CPV-10-GE-CO2-8), and some added features, such as more connector options (the CO has only one option: a single M12; the CO2 can use DB9M, dual M12, or terminal block), and a connector for adding additional CPV valve blocks to the same fieldbus interface.

Searching on google for model name (CPV-10-GE-CO-8 or CPV10-GE-CO-8) and number (175481) didn’t turn up anything useful. You have to search on Festo’s website using the full text search. For example, searching for CANOpen returns the Info 219 document (Festo CANOpen products overview) and on page 3, the CPV-10-GE-CO-8 manual in English, but not the CPV-10-GE-CO2-8 manual.

The best way is to use Festo’s full text search with the manual part number or  manual designation. The problem is to know what the manual part number or designation is. Fortunately you do not have to guess; that information is available from other sources, such as the Info 201 PDF (Fieldbus Direct products) and Info 219. For older products, it’s fortunately that Festo is logical; the second generation valve terminal’s manual designation is P.BE-CP-CO2-EN, and the original product’s manual designation is P.BE-CP-CO-EN.

The same logic applies if you are trying to find information on other Festo products, such as the CPV10-GE-DN2-8 DeviceNet valve terminal – you need to find the manual designation (in Info 201 or Info 218 (DeviceNet products)), and do a full text search on Festo’s website using the manual designation.

Here are some direct links to the Festo CANOpen information (all links are to PDF’s):

August 13, 2008   12 Comments