Posts from — June 2009
It appears that Alibre is now trying to keep Design Xpress (the free version, with limitations such as five unique parts per assembly) a secret.Â There are now no references to Design Xpress on Alibre’s home page or Products page.Â Many of the links, such as the product page for Design Xpress and the feature comparision, now return “Page does not exist” errors.Â However, a page giving the differences between Design Xpress and the Design trial still exists.
Although I haven’t tried downloading and installing to verify, it appears Xpress still does exist, since the registration page for the Design Professional trial still says: “After 30 days your trial converts to Alibre Design Xpress, which has no time limit.”
Go here for my latest MCAD news posts.
June 24, 2009 6 Comments
By default, the middle button on my Thinkpad’sÂ Trackpoint is set to a proprietary scroll mode.Â This proprietary scroll mode doesn’t work in many applications (although sometimes changing config files can fix that), but the real problem is that I need the Trackpoint to act like a three button mouse.
For example, in CoCreate PE, I need all three buttons to easily manipulate the model: Ctrl+Right mouse button pans, Ctrl+Left zooms, and Ctrl+Middle rotates.
At least in Windows Vista, the Trackpoint configuration pageÂ is not a model of clarity, but after some googling and playing around, I’ve found two configurations that make theÂ center Trackpoint button work like the middle button of a 3-button mouse.
The TrackPoint setup is a page on the Mouse Control Panel applet.
The first configuration is to select Neither for the Choose Scrolling or Magnifying Glass Functions.Â Then the middle Trackpoint button works like a middle mouse button, but there is no extra scroll mode.
The second configuration is to select Scrolling for the Choose Scrolling or Magnifying Glass Functions, then press the Settings button, and select Smooth for the Scrollling Type. This is my favorite, since I can use the center buttonÂ both as a third button, and also to scroll horizontally and vertically.
June 20, 2009 4 Comments
I’ve just passed the two year point (and 75 posts) on this blog, still averaging about a post every ten days.
My plan for the immediate future is for more on CANOpen and PCBs, partly because that is what I am working on for other projects.Â I may also add some embedded adventures, which isn’t directly related to factory automation, but I’ve always been interested in embedded computing — and embedded computing is the foundation of industrial automation.
I haven’t forgotten about other areas; I will still write about other topics such as using version control.
I do need to spend some time upgrading the site itself – but I have no plans for adding advertisements.Â They wouldn’t bring in enough money to be worth the hassle (web hosting is an incredible deal – I’m paying less than $8/month).
I am still thankful for all the useful information I’ve found at other blogs, and I hope I’ve helped some people out with this blog.
June 5, 2009 No Comments
There are two million different Ethernet field-bus standards.
OK, there aren’t really that many, but it seems like there is.Â Which one to use?Â One approach is to look at the suppliers you like and see who they support.Â For example, I like AMC and Copley drives; they both have CANOpen drives, but for Ethernet, Copley only sells EtherCAT drives and AMC only sells Ethernet PowerLink drives.
I don’t have time to list all the vendors I’d normally consider and what standards they support, but I did notice they almost all use one of four choices:
- The motion control vendors use either EtherCAT or Ethernet PowerLink
- The embedded PC / PLC / Input-Output vendors support Modbus/TCP or Ethernet/IP.
Also, the IEEE-1588 precision time protocol (used by Ethernet PowerLink and Ethernet/IP CIP) is going mainstream in a big way; I will write more about this topic later.
I find it interesting that the drive vendors and I/O vendors use different standards; I wonder how many people need a lot of motion and a lot of I/O.
And, yes, my view is very much a personal,Â North American, discrete automation view.Â But I’m not saying any of the other field-bus choices are bad; just apply the same approach with your supplier list.Â For example, if your preferred vendor is Siemens, it’s obvious which way you should go…
June 5, 2009 3 Comments
If you like beautiful food pictures , you should visit Little Bear (xiao xiong)’s blog (note that you need Chinese character support to see the site properly)Â She is a Taiwanese lady currently living in Britain who loves to cook, and certainly takes great pictures — I get hungry just looking at the pictures.
Of course, it’s much better if you can can read Chinese, although many of her creations have titles in English (as does her book, The Taste of My Life).Â But even if you can’t (like me), it’s still worth checking out for the always great pictures and sometimes very creative recipes.Â Just don’t expect to be able to recreate the dishes without knowing Chinese — for example, the green layer at the bottom of her luscious looking desert on the cover of The Taste Of My Life is made from peas.
Another good food site is Clove Garden — the pictures aren’t as artistic, but it’s in English.
June 5, 2009 No Comments
I’ve discovered a lot of neat automation components over my decade plus doing system integration.Â Unfortunately, I haven’t been able to use most of these products, but I’m starting a new series to highlight the most interesting ones.
Today’s focus is piezoelectric motors.
A piezoelectric material generates an electrical potential when stress is applied.Â The reverse piezoelectric effect is when applying an electrical potential creates a stress in the material, changing its size slightly (typically by 0.1% or less).Â This change in shape can be used in several different ways to create motion.
I first heard about piezoelectric motors back in the 1980’s when Canon introduced the traveling wave ultrasonic motors with their EOS autofocus camera system.
The first industrial piezo motors I heard about where piezo actuators, which just use the change of size in the piezo material to create movement.Â This motor type is highly accurate (<1.0 nm), but the maximum move size is very small (typically <100 micron, although I’ve seen up to 500 microns).Â Â For longer moves, you have to combine a traditional stage with the piezo actuator.Â A variety of companies make this motor type; the ones I think of first are PI (Karlsruhe, Germany) and Mad City Labs (Madison, WI, USA).
Then I heard about the Nanomotion (Yokneam, Israel).Â Nanomotion motors work by driving a piezo leg against a ceramic plate in an ellipse at high frequency.Â Their industrial motor capabilities include:
- The same motor can be used for linear or rotary motion (with circular drive strip).
- When power is off, the motor holds the current position.
- Travel up to 2000 mm, speeds of over 200mm/sec
- Force up to 3.2 kg-f
- Motor can be operated in DC (actuator) mode to provide nanometer level precision.
- Good for some specialized applications, since the motors are non-magnetic, and vacuum-compatible versions are available.
You must use a Nanomotion amplifier; analog input is standard,Â butÂ a CANOpen interface is available (it’s more expensive, since it uses the same analog amplifiers internally).Â The amplifiers generate the high voltages (around 300V IIRC) required to drive the motors.
Nanomotion also sells high precision linear and rotary stages.Â The rotary stages start around US$5000; just a motor and drive combo is around $1000 (but as always, check with Nanomotion for exact pricing).Â Allmotion is now selling drives (controller and amp) for the Nanomotion HR series; pricing starts at $395.
A few years ago Nanomotion was acquired by Johnson Electric, a large Hong Kong-based manufacturer of motors and such, since Johnson Electric wanted to use their technology for cell phone camera modules.Â Now Nanomotion produces small motors, zoom lenses modules, zoom camera modules, and custom driver ASICs, although you might need to be a high volume OEM to buy some of those products.
Next I heard about Piezo Motor AB (Uppsala, Sweden) which makes the Piezo LEGS and PiezoWave motors, which are also sold by Faulhaber (MicroMo in the US).Â This Faulhaber link gives a nice summary of the standard PiezoWave linear motor and Piezo Legs linear and rotary motors.
The Squiggle motor works by creating ultrasonic vibrations that cause a nut to travel in or out.Â They are oriented towards small, large volume applications.Â New Scale’s standard motors range from 6mm travel and 0.3N force to 50mm travel and 5N force.
New Scale has an extensive product line, including standard motors, custom motors, driver ASICs, driver boards, development kits, USB control and driver,Â standard stages, and magnetic position sensors.
New Scale has a web store that sells a variety of their products — I like it!
DTI Piezotech is part of Discovery Technology International which makes bioinstrumentation.Â Their initial product was a rotary motor (the first I heard about); IIRC, initially they only sold the motor as part of a complete, high precision stage.Â Now they have really broadened their product line, with a variety of sizesÂ of both linear and rotary motors.
Standard rotary motors range from 2 mM-m to 6 N-m force; linear motors go up to 50N-m and 1,000 mm/sec.Â Like Nanomotion, DTI linear motors can also operate in actuator mode for ultra precise positioning. Â I couldn’t find much information on their drivers, but they do have development kits, with controller boards, available.
One of my readers (thanks, Bob!) mentions yet another company, Elliptec (Dortmund, Germany), with yet another approach (piezo controlled lever moving a gear seems like a decent description).
I took a quick look at PI’s web site; they now sell a broad range of piezo motors, including actuators, rotary motors, and linear motors.
Finally, while doing research for this post, I came across PCB Motor (Hillerod, Denmark) which makes parts that can assembled on PCBs to create motors on printed circuit board.Â They have on-line ordering of their development kits.
BTW, the wikipedia piezoelectric motor page is pretty weak – it doesn’t cover most of the companies or approaches I cover.
I learned a lot writing this blog post – I hope you enjoy it!
Update Feb 2011: Another company making piezo motors is CEDRAT of France.Â They make short range piezo actuators with their own technology, such as the APA (amplified piezo actuators).
PI’s products are definitely not inexpensive, typically at least several thousand dollars for motor and controller (that’s not to say they aren’t worth it, but I like to have an idea of costs).
Update Feb 2013: see my Piezo Motor and Piezo Position page for some additional companies.
June 5, 2009 1 Comment
Me getting old?Â Not so good.Â Wine getting old?Â Very good.
I’ve been enjoying drinking some wine I bought some years ago, back when I visited the Sonoma wine country often.Â Then I didn’t drink much wine for 3-4 years.Â It’s interesting to taste the difference the years make.
Some say that wines have a peak age — they don’t taste as good before or after that time.Â I agree — and I love the taste of properly aged red wines.
So what have I been drinking?
- 1999 J Fritz Old Vine Zinfandel — an excellent wine even when new (~2001), it’s even better now; smoother, more mellow but still with a strong tannic afterbite.
- 2001 Beringer Nouveau red table wine — pretty nice now.Â Again, it’s mellow and smooth; I suspect it’s at its peak.
- 1999 Pinot white wine — didn’t age well, I only ended up drinking a bit.Â In general, whites don’t age well.
I’m looking forward to tasting how my other wines have aged (such as a Rabbit Ridge Barbera).
June 5, 2009 No Comments