Posts from — July 2009
Industrial style does matter.Â Â That’s one reason I like IDEC’s LW7L flush mount pushbuttons.Â Recently I was looking at some of our old equipment with Telemecanique pushbuttons that stick out over 5/8″ — those buttons are functional, but look dated.
The LW family of buttons is extensive (well over 10,000 combinations are available), but the models I like are theÂ LW7L-M1C64MG and similar.Â What is good about them?
- They only need a light touch to operate (lighter than some other IDEC push buttons such as the HW2L series)
- High quality
- Long life LED lights available in amber, green, red, blue, white, and yellow.
- Powered directly by 24V (no resistors to worry about — I’ve destroyed LED lights from other companies).Â 6V, 12V, 120V, and 240V models are available, but I always use 24VDC.
- They are easy to install.
- The price is reasonable (around $30).Â The Telemecanique buttons were much more expensive.Â Â They aren’t the cheapest (e.g. the HW2L buttons are about $20), but I think the difference is well worth it because of the next point.
- They look great, with the square shape and flush mounting.Â The traditional round, stick out 22mm push button makes equipment look like a retro-encabulator from the 1950’s.Â I consider the extra cost over the HW2L buttons a marketing expense.
I also really like IDEC’s XW series of E-STOP switches — especially the models with a LED light.
July 10, 2009 No Comments
I enjoy reading mysteries, especially the classics (“Golden Age”).Â I have no interest in police procedural novels.Â Most of the time I’m not interested in hard-boiled detectives (e.g. Mickey Spillane).Â I remember one time listening on XM radio to a old time radio detective show – it was filled with over the top metaphors and cliches.
But the best hard-boiled writers are good.Â To be exact, Raymond Chandler and Dashiell Hammett are good, and I’ve read most of their stories.Â Recently, I bought Chandler’s The Simple Art of Murder — and of course I read it immediately, and enjoyed it.Â Those short stories are a nice change from the Marlowe novels.
But I don’t agree with his introductory essay on detective novels.Â Chandler says the goal of fiction is realism — but it’s not: fiction exists to tell a story, whether sung by a bard, recited by a poet, printed in a novel, or shown on a movie screen.Â Ideally, fiction should tell a story about interesting characters with style, and illuminate part of the fascinating world we live in, a world filled with all kinds of people (I strongly agree with Chandler that there is no such thing as a boring topic).
No fiction is realistic: Chandler and Hammett are not exceptions.Â Hammett’s The Gutting of Couffignal is no more realistic than The Red House.Â Chandler’s stories, set in Los Angeles, make Los Angeles sound like what I imagine Las Vegas was like in its gangster days.Â Â If Chandler was realistic, his stories would’ve ended quickly, because his detective would’ve been shot and killed, or retired with multiple concussions, instead of persisting through many narrow escapes and thorough beatings.
And I don’t doubt that LA has had, and still has, many problems with gangsters, gangs, and murder, but I don’t think his stories ever matched the typical life of most inhabitants of Los Angeles.Â Â Frankly, I suspect Las Vegas was never really like its gangster image for most people, either.
I could argue that for a murder novel, you need to talk about those who are likely to deal with murder, such as detectives, gangsters, and the police.Â But I don’t believe most murder and violence were (or are) caused by gangsters.
And it’s definitely not realistic today.Â Where I live, most murders aren’t gang related; none of them sound at at all like something from Chandler or Hammett.Â There aren’t any gambling joints.Â Frankly, Jane Austen is a lot more realistic — I know several people who sure act a lot of characters in her novels.
But realistic ficture isn’t what we want.Â Heck, even look at “reality” TV — of course, it’s time compressed to only show the more interesting interactions, and the producers try to set the show up to generate conflict. Â I know most of my life wouldn’t make for a interesting novel.
July 10, 2009 1 Comment
In an article in Control Engineering, Steve Feketa of Rockwell claims that magnetic linear encoders are available for $200 for a 1 meter encoder, while optical linear encoders can cost up to $2000 for a 1 meter encoder.
If you’re paying $2000 for an optical linear encoder, you’re either getting a very high resolution encoder, a very rugged encoder, or some golf at the country club for the encoder manufacturer’s sales team.Â I can buy a nice optical linear encoder with a 1 meter scale for substantially less than $1000.
But I can’t find any information on inexpensive magnetic (or magnetorestrictive) linear encoders.Â I do know of inexpensive optical linear encoders from US Digital and Avago that are under $200 for 34″, but they are hard to mount and the resolution is only 12.7Âµm.Â I found that Heidenhain, Renishaw, Netzer, and Temposonics (magnetorestrictive) all make magnetic linear encoders.Â Â I couldn’t find any pricing, and I’m not going to spend a lot of time trying to get quotations when I’m not ready to buy one.Â I suspect that Netzer is the only one that might be close to $200 for a 1 meter length.Â OK, New Scale Technology’s Tracker is probably under $200, but its length is only 8mm.
Why am I interested in low cost linear encoders?Â Because the current cost of linear restricts their use to when I really need them (I’ve used linear encoders twice in > 10 years of machine building).Â Even a low resolution linear encoder is helpful to minimize problems from backlash, and to provide feedback for linear motors.
For the hobbyist, eBay is one solution.Â I recently bought two MicroE M2000 linear encoder read heads + electronics on eBay for a very reasonable price.Â True, I don’t have the scales, but I’m not sure where I’ll use them, so that’s OK.
July 10, 2009 1 Comment
I was having weird problems trying to run CoCreate PE on my Thinkpad: sometimes CoCreate would complain that the display resolution had changed, the model would disappear all the time (just from moving the mouse around), and such.
My Thinkpad has an Intel GMA X3100 integrated graphics chip (also known as the Mobile Intel 965 Express Chipset).Â It’s not the greatest mobile chipset, but I was more interested in a small laptop with long battery life, and the laptops with mobile Quadros (e.g. Lenovo W700) are large, heavy, and have short (OK, normal) battery life.
Anyway, I found a tip via the CoCreate Users forum: turn off hardware graphics acceleration by setting the SDPIXELFORMAT environment variable to SOFTWARE; detailed instructions are here.Â So far after making this change, CoCreate has been stable, and speed is still fine.
July 1, 2009 1 Comment