My Electro-Craft E-3618-E-F00AN motors are a great example; even using my best google-fu I couldn’t find any data online, just people trying to sell them or repair them.  I finally hit paydirt when I went looking for, and found, an old paper Electro-Craft catalog from 1993.  Sometimes having packrats around is good….

The posts include a number of simulations which are helpful in understanding the different control topologies.  However, there is still no substitute for spinning actual motors.

Commercial controllers are great at getting you up and running quickly, but don’t let you play with different control techniques.  For learning, motion control development kits are the way to go.

My dev kit is TI’s DRV8312-C2 kit with a F28035 DSP, DRV8312 brushless DC driver chip, and servo motor (unfortunately TI didn’t include a dual shaft model, but I have plenty of servo motors with encoders).  TI’s ControlSuite software provides a variety of control methods.

Since this technology uses capacitive sensing, the buttons are non-contact and should have a long life.  However, they’re still very short stroke and thus provide very little mechanical feedback.  Microchip’s demo used LED point lights to provide feedback.  Microchip’s demo kit currently isn’t available for sale, but they said it was coming sometime, probably for less than $100.

You could use this technology to make ESD-safe buttons.  However, since the metal needs to bend a bit, it won’t be as rugged as the more expensive anti-vandal buttons.

I’ll probably buy the demo kit when it comes out, because it’s a cool gadget…

It’s tough; in some ways the US is very insular.  Unless you’re lucky to live in the right area, you can’t find A4 on the shelf.

The best source is larger Daiso Japan stores.  At least some larger ones have an impressive selection, including very affordable plain white A4 paper ($1.50 for 100 sheets = $7.50 per ream), colored A4 paper, pre-punched A4 paper, heavier A4 paper, and A4 photo paper.  However, some of the smaller stores only carry a small selection, such as the punched and colored papers.  The Daiso stores I looked at carried a decent selection of A4 binders.

The only other source I found is Maido / Kinokuniya stationery, but unfortunately their A4 paper is very pricey.

There is a another good solution: most of the office chain stores (Staples, etc) will have HammerMill A4 paper (ream or case) delivered to the nearest store for free, for under $10.  Online prices, including shipping, are about the same.

CO-RJ45-PWR

I created the CO-RJ45-PWR so that I can easily monitor my RJ45 CANOpen network and, if needed, provide power to CAN_V+.

My Trac site has the details, and this post has the background information.

Since all of my other adapters provide CAN_V+ connections, I doubt I’ll use that capability often.  I’ve already used the board several times to investigate CAN buses.

I used this board to try out Phoenix Contact’s PST/PT series of removable terminal blocks.  The main reason I used them is the pin-strip header makes a great connecting post for grabber-type oscilloscope probes – but if you want to use discrete wires, just plug in the screw terminal socket.

The PT terminal block sockets are  very affordable, and some models, including the one I choose, can be mounted in three different positions.

On the down side, the polarized pin-strip isn’t readily available (so be careful when plugging the socket into the header) and the socket is only available with screw terminals (I prefer spring clamp).

CO-TB-RJ45

The CO-TB-RJ45 connects a terminal block to 2 RJ45 jacks, with optional, flexible connection to CAN_V+.

My Trac site has the details, and this post has the background information.

I created this board so I could connect anything to my RJ45 CANOpen network.  Since I’ve always liked the flexibility of removable terminal blocks, I used them for both the CAN and V+ terminals.

CO-M12-RJ45 connected to a Festo CPV10-GE-CO-8

The CO-M12-RJ45 converts a standard CANOpen M12 device connector to 2 RJ45 jacks, with an optional, flexible connection to CAN_V+.

My Trac site has the details, and this post has the background information.

I created this board to make it easy to connect my Festo CPV10-GE-CO-8 and my Norgren VM10  pneumatic manifolds to my RJ45 CANOpen network.  These manifolds use a 5-pin M12 circular plug connector with type-A polarization for the CANOpen connection.  They do not require power on CAN_V+, but I included connections to CAN_V+ in my design in case I need it in the future.

So far I’ve discovered one big issue with the board: the connector is a bulkhead connector.  It needs a panel with the proper sized cut-out to mount the socket’s threaded nut which fits on to M12 plug’s threads.  The picture above shows the missing locking nut on the board while the power cable’s locking nut is clearly visible on the right.

As far as I can tell, all the right angle PCB M12 socket connectors have the same issue.  Right now I’m just letting the M12 socket rest in the M12 plug, but that’s not very secure.  If I need a secure setup, I’ll try to rig up some kind of a hack to hold the nut to the board.

CO-HDR-RJ45 Mounted On A Wago 750-337

The CO-HDR-RJ45 converts a standard CANOpen 5.08mm terminal block header to 2 RJ45 jacks, with optional, flexible connection to CAN_V+.

My Trac site has the details, and this post has the background information.

I created this board to make it easy to connect my Wago 750-337 and Beckhoff BK5150  CANOpen  K-bus interfaces to my RJ45 CANOpen network.  These interfaces use a 5-pin 5.08 mm terminal block header for the CANOpen connection.  They do not require power on CAN_V+, but I included connections to CAN_V+ in my design in case I need it in the future.

So far I’ve discovered one minor issue with the board: the Phoenix Contact inverted header I used does not perfectly fit the Wago header used by the 750-337.  I had to break off one tab; if you look at the picture above, you can see that the top Phoenix tab does not line up with the cut-out for the top tab.

I typically use Phoenix Contact terminal blocks over Wago because they are much more readily available from my favorite catalog distributors, Mouser and Digikey.

I also have a Wago 750-338 interface which uses a DB9M connector, but based on my eBay monitoring, I’d say the terminal block models, such as the 750-337, are substantially more popular.  If I were buying new, I would use the 750-338 instead of the 750-337 (since I prefer cables over terminal blocks), or more likely the 750-838 (PLC version of the 750-338) since I’ve found that programmable logic + distributed I/O is a great combination.

CO-DB9-RJ45-2 Adapter connected to an AMC DX15C08 Drive

The CO-DB9-RJ45-2 converts a standard CANOpen DB9M connector to 2 RJ45 jacks, with optional, flexible connection to CAN_V+.

My Trac site has the details, and this post has the background information.

The AMC drive pictured is the reason why this board exists: I have a bunch of DX15C08s and a couple DX60C08′s and wanted to get them running, but they require 9->13VDC on the CAN_V+ line.  So I created this adapter to solve that problem with its CAN_V+ connection, and added the RJ45′s because it’s so much easier than trying to daisy-chain DB9s.  (I did think about staying withDB9s).

The design is called the -2, because I have a CO-DB9-RJ45-1 mostly designed, which uses ultra low profile RJ45 jacks in a DB9/DB25 gender changer backshell with 2.5mm terminal blocks.  The board shape is complicated, and I haven’t had the PCB made yet.

This board shows how it’s hard to get everything right the first time: I put the TB1 terminal block header on the wrong side for the DX15C08 servo drives.  Look at the picture and you can see the HD44 cable is right next to the terminal block.

My solution was to replace the pluggable terminal block with a compatible fixed terminal block that doesn’t extend past the PCB board.  That works, but it’s still a tight squeeze.

The board is shown with my RJ45 terminator, which is pretty slick and affordable (~$2).  I’ll try to document the terminator sometime soon.

CANOpen Adapters

I’ve finally create Trac pages for my CANOpen adapters.  I will be highlighting each adapter in a blog post, starting with the CO-DB9-RJ45-2.

I created these adapters for two reasons:

1. I’ve standardized on RJ45 cables for my CANOpen networks, because daisy-chained RJ45 cables are cheap, simple, and work well.  However, many of my CANOpen devices do not use RJ45′s, so I created adapter boards from their connectors to dual RJ45 jacks that are perfect for daisy chaining.
2. Some devices require power on CAN_V+ to power their CAN line drivers.  Unfortunately, most CAN interfaces do not provide any power, or any way to get power, to the CAN_V+ wire.  Also, I need to provide incompatible voltages to different devices.  So I added flexible connections for CAN_V+ to my boards.

After using the boards, I’ve found a couple things that could be improved; the details will be covered in the board’s blog post.

Most of the boards use a similar setup for CAN_V+:

• CAN_V+ from the power terminal block (TB1) is always connected to the device’s connector.
• CAN_V+ from TB1 can be connected to the right and/or left RJ45 jack using jumpers.

This setup gives a lot of flexibility: you can power each device that needs CAN_V+ individually, you can power part of the network (left or right), you can power the whole network (left and right), or you can have separate power domains (by not connecting one or both of the jumpers).

If you start doing fancy stuff (such as different CAN_V+ voltages on different network segments), be careful.  For example, if you have an AMC DX15 segment (+12V) and a Baldor e100 segment (+24V), and accidentally move the AMC to the Baldor segment, you will fry the AMC’s CAN line drivers.

The CO_RJ45_PWR board is a little different, since it’s in-line.  Basically, CAN_V+ from the incoming RJ45 jack (J1) is always connected to the 8-position terminal block (P1), and CAN_V+ from the power terminal block (TB1) can be connected to J1 or J2 (outgoing RJ45 jack) using jumpers.

I had the PCBs made at Gold Phoenix, which is a good choice if you need several boards each of different types.  There are many other good PCB fabs.  I am not providing my Gerber files, since different PCB manufacturers may require different formats (units, resolution etc); there are plenty of resources on how to create Gerbers from Eagle on the internet.  If you can’t figure it out, you can always use a PCB fab house that takes Eagle PCB files directly.

Update 3/31/2012: Here are links to the different boards.

• The CO-DB9-RJ45-2 converts a DB9M CANOpen connector to dual RJ45 jacks.
• The CO-HDR-RJ45 converts a 5-pin, 5.08mm CANOpen terminal block header to dual RJ45 jacks.
• The CO-M12-RJ45 converts a M12 CANOpen connector to dual RJ45 jacks.
• The CO-TB-RJ45 converts a 5-pin terminal block to dual RJ45 jacks.
• The CO-RJ45-PWR provides inline monitoring and access to CAN_V+ for RJ45 networks.