Category — Series

What software do I like on my service laptop?

• All my development software.  I never know when I might need a particular software package.
  • However, licensing can be an issue; nobody wants to pay extra money for a license that sits mostly unused on a laptop.  Some software allows for multiple installations.
  • If the software only allows for one installation, I prefer using a dongle to a software key, because it’s easy to move the dongle around — and way too easy to “lose” the software key (I’ve seen it happen every time with software keys, which why I hate software keys).
  • Software licensing based on the MAC address or such, that can be moved around easily (e.g. return key via internet, then check it out on another computer) is better, but is still a hassle.
  • Of course, the best vendors say: “You can copy the software; just don’t tell us” (said to me by a saleswomen for a large German automation vendor).
• Electrical Schematic viewer
  • I don’t always have a paper schematics with me, so it’s important to be able to view schematics on my laptop.
  • Since our schematics are in DWG files, I use eDrawings as a convenient DWG file viewer.  You can also use a full AutoCAD clone; DoubleCAD XT (Windows only) and DraftSight (Windows, Mac, Linux) are both high quality, free AutoCAD clones.
• Merge software with directory comparisons
  • I’ve found file comparison software to be a life-saver.  Version control is great, but a machine in the field might be in a different state.  I can use the directory comparison to quickly see what files have changed, and then zero in on the changes using file comparison, and then merge between the two versions if needed.  Some software handles three-way merges.
    • I just did this kind of directory comparison recently when upgrading two almost-but-not-quite-identical machines.
  • I’ve been using Araxis Merge for a long time, and have no regrets about spending my money on it.  I’ve used some free options (such as TortoiseMerge with TortoiseSvn), but I feel Araxis works better for some file comparisons.   TortoiseMerge doesn’t do directory comparisons.
• If you use a personal laptop for work, consider using a Virtual Machine (VM) to keep your private and professional lives separate.  With USB pass through features, you should be able to access USB, serial (via USB to serial converters), and networked equipment from within the VM.
• In the future, I might look at taking my version control system with me; since I’m currently running Subversion and Trac in a Virtual Machine, I could do it easily by copying the VM to my laptop.

My Toolbox series is about my tools for working on machines, including some stories.  I’m going to talk about my tools; your toolbox will be different, but hopefully I’ll give some useful ideas.

Yeah, I’m a software guy, but as the automation software guy, I have the privilege of understanding the whole machine and making sure it is all working right.  That’s why I have a toolbox filled with mechanical tools and electrical test equipment, but I’ll start with service laptops.

Service Laptop

• I’m using Win7 64-bit on my own laptop, but Win7 32-bit is probably the best choice for a field service laptop,  since you should not need >3G RAM, and many device drivers are still not available for 64-bit Windows.
• Since almost all automation software is Windows only, you really have to use Windows.
  • Siemen’s SoftComfort Logo! development environment is a notable exception (it’s written in Java).
  • However, if you can talk to all your equipment via USB (including USB to serial converters) and Ethernet, you could use Linux or Mac OS X as your host OS and run the Windows software in a VM (Virtual Machine) with networking and USB pass through for outside access.  Or you can dual boot.
• I’m partial to Lenovo Thinkpads because of their excellent keyboards and overall quality.  Besides, most Thinkpads support using a FDE (full disk encryption) hard drive, which is a good idea when venturing out with gigabytes of proprietary information.
  • Not all Thinkpads come with with FDE drives, but it’s an affordable do-it-yourself upgrade.
  • Thinkpads are more affordable at the Lenovo Outlet, and you still get a 1 year warranty.  If an older Thinkpad is good enough, and a shorter warranty is OK, then TigerDirect often has great deals (<$400) on off-lease Thinkpads.
• Of course there are plenty of other good possibilities.  My advice is always get a business class laptop; I’ve seen way too many problems with consumer laptops.

Don’t forget the cables

• I typically bring along an extra RJ-45 cable, a standard DB9M/F serial cable, USB extension cable, USB A to micro-B cable, Panasonic FP0 serial cable, and USB to serial port converter (since my laptop doesn’t have a serial port).
• I normally don’t bring along all the special serial stuff, like null modem (laplink) cables, DB9/DB25 cables, and assorted gender changes.  I’ve only needed something weird once in the past 5 years.

Other Computer Hardware

• A 4G or larger USB memory stick.
  • I frequently have to transfer files without using a network.
  • If you work with really old computer systems, a USB floppy drive would be useful.
  • Don’t forget the memory stick!  Always remember to put it back in your bag or pocket.
• 3G/4G wireless is a nice option, so you can access the internet to research problems, download files you forget to do earlier, and such without needing access to the customer’s network.
  • On the other hand, 3G is another monthly fee (typically $40-$80/month in the US) for a service that’s typically not often needed.  If AT&T does complete its acquisition of T-Mobile, expect prices to go up.
  • Pre-paid (from Virgin Mobile and others) gives the option of paying only when needed, but pre-paid is more expensive for heavy data use. Walmart probably has the best pre-paid deal: $20 for 1G for 1 month.
  • Another option is tethering (via USB cable, Bluetooth, or WiFi) to a cell phone with 3G/4G.  However, tethering usually adds another monthly charge (often about $15) on top of the data fee.

Before starting to put all the pieces together, spend some time planning.   Things to think about include:

• What is your naming convention?  A good naming convention for parts and assemblies really helps you remember what is what.  Which is a more useful name for a connector model, Part_21 or AMP 5499206-IDC-26?
• How are you going to assemble the part?  Are you going to use any sub-assemblies?  Good use of sub-assemblies makes assembling the model easier and more logical.
• Do you have all your part models?  I like to have all my models ready before assembly, but you could start with what you have, and download or create as you go.
• Do you need to modify any manufacturer provided models?  For example, your part might be slightly different from the closest manufacturer model, or you may need to modify the part (e.g. by adding reference geometry) so you can easily add constraints.
  • I’ve come across both these cases, and will discuss them more in the future.
• Are you going to directly import your manufacturer models into your assembly, or convert them into Alibre parts first?  Alibre Design 2011 can directly import STEP, SAT, and IGES parts into assemblies.
  • IIRC, previous Alibre versions couldn’t directly import into assemblies, which is why my current designs convert all imported parts into Alibre parts.

Here are my tips on adding constraints:

• Come up with a naming convention for constraints: J1_Align_Pin1 provides much more information than align22.
• Position the parts so you can see all the features you plan on using to mate the parts together.  I really like using the triad tool, with minimum motion mode off.
• I’ve had much better results using the manual constraints dialog than trying to use quick constraints.  Sometime I’ll give quick constraints a try again.
• I’ve found it’s always necessary to move and zoom all around, and every time I use the icons, my constraints dialog goes away, so shortcuts are the way to go:
  • Pan: press and hold middle mouse button, then move mouse pointer
  • Rotate: position the mouse pointer where you want to rotate, then press and hold right and left mouse buttons, then move mouse pointer.
  • Zoom in: press Page Up
  • Zoom out: press Page Down
• Be careful where you click; it’s easy to select a feature you don’t want.
• I like anchoring one part (for example, the PCB) so I know which part will be moving when I add constraints
• Check the defaults.  Often, the mate constraint will show the current distance between parts, so I have to change it to zero.
• Use your PCB layout as a guide.  OK, if I could get Alibre to handle the silkscreen layer this wouldn’t be necessary, but it’s handy when I have a PCB full of holes and no silkscreen information on the PCB model.

The final step in creating a 3D PCB model is to assemble all the pieces together.  Normally Alibre assemblies are created by constraining the parts.

A constraint limits how two parts can be located relative to each other.  Three constraints fully constrain a part.  For example, think of mating a through hole connector with 10 pins in one row to a PCB.  You could add three constraints like this:

1. Use an Align constraint to align the axis of the connector’s pin 1 with the PCB hole for pin 1.  Now the connector is limited to two degrees of freedom: it can move close and farther from the PCB and it can rotate 360 degrees  around the pin-1/hole-1 axis.
2. Use another Align constraint to align the axis of the connector’s pin 10 with the PCB hole for pin 10.  Now the connector cannot rotate: it can only move close or father from the PCB.
3. Finally, use a Mate constraint with a zero offset to mate the bottom of the connector with the top of the PCB.  Now the connector cannot move at all; it is attached the the PCB just like you had perfectly soldered a perfect connector to a perfect PCB (pins centered in the holes, connector just touching the PCB, etc).

That sounds pretty easy, right?  Well, the reality is often different.  Extruding a PCB is straightforward.  Mating parts together is not; there are many possible ways of mating the parts together, and the best approach depends on the specific parts and PCB.  I think MCAD assemblies are complex enough that an expert could write a book just about assemblies (and I’m definitely not an expert).

I haven’t found a lot of practical information on Alibre assemblies.  My findings so far:

• You should definitely read the Alibre Design User Guide chapter on assemblies.  It covers what’s available, including about 20 pages on constraints, but is brief and descriptive.  It does not give any examples or practical advance.
• Based on the table of contents, the Learn 3D CAD book also only covers constraints briefly (about 20 pages), but still looks like it’s worth the price, since it has a real world example, and advice on overall design (top down vs bottom up).  I’m planning on getting the PDF version when the 2011 update is available.  Note 10/5/2011:  the Learn3DCAD website is no longer active, so this is no longer an option.
• The Alibre forums look useful if you have a specific question, but aren’t a tutorial.  Also, if you’re on maintenance, there’s always tech support for specific questions.
• I’m not sure how useful Alibre’s paid training materials (DVD, exercise book, online seminars) since they don’t provide detailed information on the contents.  I suspect they wouldn’t cover some of the problems I’ve had.

Next up in this series: some specific tips from my experience.

I haven’t forgotten about my Eagle 3D PCBs with Alibre series.  There is one big topic left:  putting all the pieces together using Alibre assemblies.  Unfortunately, my experience is that mating parts to create assemblies is often very tricky (especially when you’re using imported parts), and there’s not a lot of resources.

I’ve done a fair amount of research, but it’s hard to give the same kind of step-by-step instructions for mating parts in an assembly that I did for extruding the PCB.

Also, I’ve just re-done my blog PC (a Thinkpad X61t) with a bigger hard drive and Windows 7 64-bit, so that’s sucked up a lot of time recently.   (Side note: there’s not a lot of 64-bit software out there yet.  But so far I’m quite please with the upgrade.  Alibre Design 2011 does have a 64-bit version, but only for Professional and Expert users.)

What I’ll probably do is write an article (hopefully in the next week) with some notes on how I mated everything together.  I’ll post the files in Alibre Design 2011 format so you can see what I did.

Then this series will be complete.  But I do plan on writing about some Alibre tips that are sort-of related to this series.  And I do have a new series planned that’s more automation related.

I think it’s interesting that there are so few switch mode power supplies (SMPS) designed for powering motors.  Motor power requirements are different from electronics; voltage regulation isn’t critical.  Servo motors benefit from a large current peak (overload) capability and sometimes need a shunt.  Steppers are best with a power supply designed to handle a rapidly changing inductive load.

A typical switch mode power supply, however, is designed for tight voltage regulation, does not have a shunt and handles over current by limiting current to its maximum rating.

Some switching power supplies are better because they have 20% to 50% peak capacity for a brief time.  I’ve seen this capability in models from Cabur (sold by ASI in the US), Puls, and Delta; I’m sure there are other examples.

I’ve used the Delta CliQ series for servo motor power, and so far they’ve worked well.  The CliQ can handle 50% over current for 3 seconds, the pricing is quite good (under $150 for 24V at 10A), but they’re only available for 12V and 24V.

The first designed for motors SMPS I discovered was the IMS ISP200/300 series, which are unregulated switching supplies specifically designed for handling the rapidly changing, inductive loads typical of stepper motors or DC motors.  IMS is now Schneider Electric, and they have discontinued the ISP series.

I don’t really consider the Galil PSR series a SMPS for motors; it looks like an ordinary enclosed switcher with an added shunt resistor.  The PSR costs $250, and is available in 24V at 12A or 48V at 6A.

I recently discovered a second SMPS for motors, the Cabur XC series (sold in the US by ASI).  They have a 72-85V output at 3.1A, 6.6A, or 13.3A, have a 20% reserve capacity when <45C, can handle 50% over current for 5 seconds, and have output over-voltage protection (equivalent to a shunt).

It’s interesting to compare the XCSF500G (72V at 6.6A) to the Logosol LS-872.  Logosol makes my favorite linear power supplies (I own a LS-1148 and use it extensively); they are relatively compact, are switch selectable between 115V and 230V input, have ESTOP inputs, front panel mount fuses, and are available in a variety of output voltages.  (The only other 120V/240V switch selectable linear motor power supply I’ve been able to find is Copley’s  DP models in their PST series, but they cost much more).

Nope, not the kind of models you find at Model Mayhem; this post is all about finding 3D models of your PCB parts.

You can always make your own, but unless you are an MCAD software expert, rolling your own will take a lot longer.

So far I haven’t had to make a model, but I’ve only used connectors, which typically have STEP or IGES models available from the manufacturer.   But many electronics manufactures do not provide models.

Here are some good model sources:

1. Always check the manufacturer first, especially for electromechanical products (connectors, switches, etc).  You might have to register first.  Also, sometimes you can get a model by asking (I’ve done that successfully with Amphenol).
2. Check out general purpose CAD part libraries.  I haven’t used any yet, so I don’t have any personal recommendations.  Ten Link’s list looks like a good starting place.
3. You might be able to use MCAD vendor specific user generated CAD libraries.  If you have good import options (e.g. Alibre Design Expert) you can try importing Solid Edge, Pro/E, or SolidWorks models.
4. Pay for model creation, using either a free-lancer or a company such as Simplified Solutions.
5. For MCAD software with an API (which includes Alibre Design), you can use this API and information (for example, from an IDF file) about the part to automatically create models — or pay for someone else’s add-in.  My earlier post has some more information on this approach.
6. You might be able to use STL, Sketchup, or 3-D POVRay models developed for projects such as Eagle’Up or Eagle 3D.  Sycode makes affordable Sketchup and STL importers for Alibre.
7. There’s always Google and other search engines.  I place web search near the bottom because a lot of models are hidden where search engines can’t find them.
8. Do it yourself; in that case, I recommend spending a lot of time and some money learning how to model well (to save you time overall).  The “some money” is best spent on books (such as Introduction to Solid Modeling NOTE: Learn3DCAD website is no longer active) or videos, although don’t forget to search for free resources and check out what came with your MCAD software.

Simplified Solutions does have some interesting solutions, including:

• An existing library of electrical components in STEP format.  Pricing is reasonable for professional use at $550 for 50 models or $1700 per year for unlimited models.
• 3D part creation at a reasonable price ($650 for 20 parts, but check on the details; you probably need to provide data in a format they like, e.g. IDF, which for Eagle PCB users means you’ll have to update your library with IDF information).
• 3D PCB model creation (they model the entire PCB).

In this post, I have a few final notes about extruding Eagle PCB DXFs.

All the files I mention are available in a ZIP file here Extrude Alibre.zip

The basic idea is simple: I have a sketch with an outline (the PCB borders) with holes in it (pads and vias) that I want to extrude.  The picture below shows a simple case.  On the left, there is a rectangle with a circle inside it (Extrude-DoubleCAD.dxf, which I created in DoubleCAD, and then imported into Alibre).  On the right I extruded it (Extrude-DoubleCAD.ad_part).

Simple Extrusion

So what can go wrong?  Here are some situation where Alibre Design will not extrude your sketch:

1. Overlapping objects
   1. For example, when two lines on the same layer both cover the same area.  The picture below shows two thick lines (outlined so it’s clear) overlapping at an intersection.
      

      Overlapping Lines

   2. A thick rectangle will extrude OK, but you can’t make one in Eagle PCB (Eagle will only create filled rectangles).
   3. If the lines have zero width, they do not overlap.  So it’s best to make sure your board’s borders in Eagle PCB have zero width.
   4. But even if you use thick borders, if you export (using my modified DXF ULP) with the Use Wire Width option off you will have a usable DXF, because in this case the ULP resets all wire widths to 0.   Since you should always export with Use Wire Width off, it’s probably OK to use thick borders, but I always still set my borders to zero width.
2. Overlapping lines on different layers
   1. This is the same as #1, except the lines cross each other on different layers.  For example, if you have a border on more than one layer in Eagle PCB, and export both those layers to the DXF, then Alibre will not extrude that DXF file.
   2. The Extrude-Different Layers.DXF file shows this scenario; below is the error message when I import and try to extrude it.
      

      Errors Extruding Duplicate Lines

3. Extruding PCB traces or silkscreen text.
   1. It’s possible to create traces or text that Alibre will extrude, but the standard DXF ULP’s output is useless.  You would have to create a very different DXF ULP.
   2. Below is an example of a DXF (Traces+Text-Extruded.dxf) and extruded part (Traces+Text-Extruded.AD_PRT) that gives an idea of what DXF exported from Eagle PCB would have to look like.
      

      Extruding Text & Traces

   3. Instead, below are some screen captures of actual Eagle PCB DXF ULP output showing the results (for no wire width, wire width, and filled wire width).  Alibre will not extrude any of these, and I haven’t found a way to overlay a sketch or bitmap on top of a surface.
      

      Text & Traces - outline

      

      Text & Traces - Wire Width

      

      Text & Traces - Filled Wire Width

I mentioned in the previous post in this series that you cannot use the standard Eagle DXF ULP to generate DXF files that Alibre can use.  Now I will go into a little more detail.

All the files DXF files I mention are available in a ZIP file here Extrude Alibre.zip

What are the problems with the normal DXF ULP?

1. It creates the pads, not the drill holes.  The picture below shows, in green, the pads created by the normal DXF ULP.  I added the drill diameters in white using DoubleCAD.
   

   Pads created by Eagle DXF ULP

   1. Notice the green  squares (which I use for pin 1).  I haven’t seen a square drill bit yet…
   2. Notice the the green square and green circle are much larger than the white circle.  This is because the DXF ULP is creating the pad outline; for each pad, Eagle adds some copper area around the drill diameter (how much depends on the active design rules).   But we want to extrude the actual hole size through the PCB, not the pad (drill area + copper area).
   3. You can get around this by creating a special set of design rules that does things like set all pad shapes to circular, pad size to the drill size, etc.  And you’d better remember to re-apply your normal design rules (or you’ll end up with a worthless board).  This approach will work OK for SolidWorks (I’ve tried it), but still doesn’t work with Alibre, because of other problems listed below.
2. The DXF ULP creates the pads using object blocks (with different blocks for the different pad shapes).
   1. The ULP creates two identical blocks right on top of each other on the same layer (17, Pads).  Alibre will not extrude sketches with overlapping objects.
   2. For some reason, Alibre does not copy the blocks correctly.  When I imported the DXF into Alibre, they appeared at the right location, but when I copied the sketch to the new Alibre part, they moved to a totally wrong location.  The picture below shows this with the DXF (Extrude-Different Layers.DXF) on the left  and the part (Extrude-Different Layers.AD_PART) on the right — the pads have moved far to the right.
      

      Problem Copying Blocks

So what did I do?  Well, I didn’t have a lot of time, and I’m not a DXF expert, so I made the minimum changed required for Alibre to work:

1. I changed the Via function to always create a circle with the drill diameter on the dimension layer (layer 20).
2. I changed the Pad function to always create a circle with the drill diameter on the dimension layer.

So far these changes have worked for me, but I should note that AutoCAD 2000 doesn’t like my changes (I haven’t tried newer versions).

The final topic: a bit on the DXF ULP options.

DXF ULP Options

• Output file is the name of the DXF file that will be created.
• Always vector font should force a vector font to be used, but I haven’t test this feature.
• Unit selects whether to use inches or millimeters.  Always remember the units you choose, because when you import a DXF into Alibre Design, Alibre needs to what units you used.
• Below I show the same simple board creating DXFs using 1) no wire wire or fill areas, 2) using the wire width option only, and 3) using the wire width and fill areas options.  For extruding PCBs, you should never select the Use wire width or Fill areas options.
  

  DXF no Wire Width and no Fill Areas

  

  DXF using Wire Width, not using Fill Areas

  

  DXF using Wire Width and Fill Areas options

Extruding the PCB – Overview

The first step to a complete 3D PCB model is to create the PCB.  The basic approach is to export a DXF outline of the PCB and its holes from Eagle PCB, import it into Alibre, and then extrude it.  It’s not as easy as it sounds.

Alibre Design refuses to extrude sketches with any overlap.  AD V11 did not show where the errors are, but V12 does (this feature alone makes V12 worth the upgrade).

If your PCB border has a non-zero width, Alibre will not extrude the PCB because the four corners overlap.  For some reason, Alibre Design does not accept the way the standard Eagle DXF script creates holes.

I did not have any success getting Alibre Design to extrude the silkscreen or trace layers, nor was I able to overlay the silkscreen or traces as a visible sketch on top the extruded PCB (maybe because Alibre Design does not support surfacing).

When extruding, CoCreate PE is about as picky as Alibre, but (like AD V12) it highlights what it doesn’t like.  SolidWorks doesn’t have problems extruding the standard Eagle DXF output.  VX Innovator is also less picky; I have successfully extruded the silkscreen layer.

I made a couple quick and dirty changes to the standard Eagle DXF creation ULP to fix the holes; the result is dxf-fsw.ulp.

Creating the PCB — Step By Step

1. Open your project in Eagle, then open the Eagle Board editor with your PCB layout.  I used the FP-SMC-1 project as an example; you can download the files here.
2. Make sure your borders have a width of 0.
3. In the Eagle PCB board editor, turn on only the dimension, via, and pad layers (layers 17, 18, and 20).
   

   Layers for DXF creation in Eagle

   

   FP-SMC-1 in Eagle set for DXF creation

4. In the Eagle PCB Board editor, run the dxf-fsw.ulp ULP.
   1. Select a file name for Output file; I used FP-SMC-1.dxf with the appropriate path for my Eagle PCB setup.
   2. The Always vector font, Use wire widths, and Fill areas setting should not matter.
   3. The units do matter: you need to know them when you import the DXF.  I used inches.
   4. Then run the script by pressing OK.
   5. You can download my resulting file here FP-SMC-1.dxf
      

      Running the dxf-fsw ULP

5. Close Eagle PCB.
6. Start Alibre Design.
7. Select the File->Import menu, select AutoCAD DXF files for the file type, select the file (in my case, FP-SMC-1.dxf), and press Open.
   1. File Units need to match the units you used when creating the DXF in Eagle (I used inches).
   2. I don’t think Maintain Projection matters.
   3. Importing Only Visible Layers makes sense.
   4. Start importing by pressing OK.
      

      Importing DXF into Alibre

8. Select the Sketch->Activate 2D Sketch menu  (or press Ctrl+K).
9. Select the Edit->Select All menu (or press Ctrl+A)
10. Select the Edit->Copy menu (or press Ctrl+C)
11. In the Alibre Home window select the File->New->Part (or press Ctrl+Shift+T)
12. Select the Sketch->Activate Sketch menu (or press Ctrl+K)
13. Select the plane to use for your new sketch.
    1. You can name the sketch.  It’s not a big deal in a simple part, but I would recommend named sketches in a complex part.
    2. I used the XY plane.  You can select the plane by either clicking on the plan in the work area, or clicking on the list of planes in the tree on the left (e.g. Planes->XY Plane).
14. Select the Edit->Paste menu (or press Ctrl+V) to paste the DXF drawing into the sketch.
    1. You could select and move the sketch around if desired.
       

       FP-SMC-1 DXF pasted onto the sketch

15. Select the Sketch->Activate Sketch menu (or press Ctrl+K) to deactivate the sketch mode.
16. Select Extrude Boss by menu (Feature->Boss->Extrude) or icon (typically the top right icon).
    1. Verify the correct sketch is selected.
    2. Use To Depth for Type.
    3. Use your PCB thickness for depth (0.062″ or 1/16″ for me).
    4. I reversed the extrude so the sketch is on top (probably doesn’t matter a lot).
    5. Leave everything else with the default settings, except you may want to name the extrusion.
    6. Start the extrusion by pressing OK.
       

       FP-SMC-1 ready for extrusion

17. Save the PCB using the File->Save As menu (Ctrl+Shift+S); mine is available as FP-SMC-1 PCB.AD_PRT
    

    The extruded FP-SMC-1 PCB

18. We are done creating the PCB itself.  Now we have to assemble the board inside of Alibre, so stay tuned.

Here is the FP-SMC-1 PCB as an Acrobat 3D PDF; if a correct version of Acrobat is installed, you can click on the PCB, and then rotate it and more.