Category — CANOpen Adventures

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
systems.

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.

Tony

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):

• Info 213 CPV system product catalog
• Info 201 CPV Fieldbus Direct product catalog
• Info 219 CANOpen products catalog
• CPV pneumatics manual, designation P.BE-CPV-EN, part number (or order number) 165 200
• CPV-10-GE-CO-8 manual, designation P.BE-CP-CO-EN, part number 175 580
• CPV-10-GE-CO2-8 manual, designation P.BE-CP-CO2-EN, part number 526 010

Embedded Networking with CAN and CANOpen by Pfeiffer, Ayre, and Keydel, RTC Group /Annabooks Copperhill, 2003.

Summary: 8.5/10, highly recommended.

The book covers the CANOpen basics well. It helps that I’m already familiar with basic CAN and CANOpen concepts (SDO, PDO, Object Dictionary, etc), but the explanations are clear, and the authors do provide concrete examples, which always helps.

The book does go into some low level details, such as CANOpen message formats. That’s good knowledge to have – I’ve never regretted learning about computing at the bit level. If you need really detailed information about CAN, then you will need another book.

The final part of the book is a CANOpen summary. I expect to be using this section quite a bit as I continue experimenting with CANOpen.

I don’t have real complaints about the book. I do wish, however, for a complimentary book specifically about CANOpen in factory automation. For example, this book does not cover DS402 (drive profile) at all.

Tony

Notes 4/21/2011: I’ve updated the links and status (but not the chart); both CANOpen books are now available.  Sometime I’d like to revisit field bus books, but it’s not a high priority.

One way of judging programming language popularity is to compare book sales. So I decided to do something similar – see how many books in Amazon.com had the names of popular fieldbuses in their title. I excluded non-English books (German Profibus users get more choices) and standards documents.

I wouldn’t choose a fieldbus on the basis of books; for example, many of the fieldbuses have good information available on the web. But it’s interesting to look at the book titles and year of publication:

• Embedded Networking with CAN and CANOpen (2003, out of print in print). The authors are trying to arrange have arranged another printing.
• CANopen Implementation: Applications to Industrial Networks (2000, unavailable available)
• Profibus: A Pocket Guide (2003, in print)
• Decentralization with Profibus DP/DPV1 (2004, in print unavailable)
• Profibus: The Fieldbus for Industrial Automation (1993, unavailable)
• Automating with Profinet: Industrial communication based on Industrial Ethernet (2006, in print)
• Design and Installation of Foundation Fieldbus Systems (2007, unavailable)
• Foundation Fieldbus (2005, in print)
• Foundation Fieldbus: A Pocket Guide (2002, unavailable)

Apparently fieldbus books do sell: several recent books are already out of print (or otherwise unavailable).

Tony

Updated 12/14/2007 with more vendors

More notes added 4/19/2011

It’s obvious I like CANOpen, but it does have its downside. Areas that could be much improved include:

• Too many connector types. OK, I can see a need for more than one connector type. But 20 types? Powering isolated CANOpen transceivers is not consistent either – I am going to design and build some interface boards to make it easier (results are here). Just giving examples from my favorite vendors:
  • My CANOpen interfaces both from Ixxat, Kvaser, ESD, Peak, and Grid Connect have DB9M CAN connectors, but do not provide any power. (The PEAK dongle can be easily modified to provide +5VDC on pin 1 and/or pin 9).
  • The DB9M connector seems standard for CAN interfaces – Kvaser, Ixxat, Softing, Peak, and Gridconnect all use it. The Ixxat USB/CAN interface has RJ-45 connectors, with RJ45/DB9 adapter.
  • The AMC DX15 uses a DB9M connector, and requires 7.5-13VDC on pin 9.  Current AMC CANOpen drives use dual RJ45s.
  • The Wago 750-337 has a removable screw terminal connector, and its isolated CAN transceiver is powered internally. (The 750-338 has a DB9 connector).
  • Copley Accelnet Panel drives (ACP-xxx-xx) use RJ-45 CAN connectors, and look like they need +5VDC on pin 8.  Copley ACP and ADP drives have a built-in DC/DC converter.
  • Copley Accelnet Micro Panel drives (ACJ-xxx-xx) use Samtec 10-pin crimp and poke connectors, and need power on pins 1 and 6.
  • IMS CANOpen MDrives (stepper motor + drive) use either DB9 or 5-pin micro (M12F) connectors, and look like they require 7-30VDC on pin 9.
  • Elmo’s Cello and Harmonica drives use a RJ-45 connector, are isolated, but don’t require external power.
  • Kollmorgen S200 Series uses 5-pin removable terminal block.
  • Technosoft IDM680 uses DB9M, and needs +24V.
  • Technosoft IDM240 and IDM640 uses what looks like a RJ-11 connector.
  • Faulhaber MCDC3003C and MCDC3006C drives use DB9M with no power.
  • Maxon EPOS uses a 4-pin Molex Micro-Fit connector, no power, and a Molex to DB9M cable available.
• Raw CANOpen is pretty primitive – certainly not a good basis for rapid development. This is a bit better than I thought.
  • Copley’s CMO (ActiveX) is free for use with their drives. CML has a license fee which is reasonable. Both are higher level interfaces, and would make working with a Copley and Wago only system easier. However, as far as I can tell, the libraries only work with Copley drives and Wago I/O modules, so if you need to mix and match, it won’t work.
  • Elmo’s Maestro Multi-Axis Supervisor and Composer software look interesting (might make CANOpen development much quicker), but I’m pretty sure they only work with Elmo’s drives.
• Software needs much more standardization – what works with what is still too restricted. To give some examples:
  • IMS requires Peak CAN interfaces (resold as the MD-CC500) to download firmware updates.
  • Copley’s CMO and CML software only supports interfaces from Copley, Ixxat, Kvaser, NI, and Vector, and only supports Wago I/O.  Setup can be done over serial or over CAN (except for Ixxat).
  • Elmo’s Interlude software supports Ixxat, Softing, and Kvaser.
  • AMC’s Driveware configuration and setup software works with CAN interfaces from Advantech, Ixxat, Kvaser, Vector, Port, Ifak, and ESD.  Newer AMC drives use a serial port for setup.
  • Faulhaber’s Motion Manager software only supports Ixxat.
  • Maxon supports Ixxat, Vector, and NI.
  • Wago appears to supply no software, just the EDS files.
• Most CAN interfaces do not include CANOpen software – it’s either not available or is yet another cost (Kvaser was the exception IIRC). Softing includes a free CANOpen API (LeanCANOpen).  Go here for my current list of CANOpen software.

So if you need to mix and match (one of CANOpen biggest advantages), you are going to have fun. Think about a system needing a high power AMC drive, some Copley Accelnet Micro Panel drives, and some IMS MDrives. You’d need a Peak CAN interface to update the MDrives, but a Ixxat, Kvaser, or Vector interface to setup the AMC and Copley drives. You’d have to use different GUI software to setup the AMC and Copley drives. And you could drive using Copley’s higher level CMO or CML libraries with AMC and IMS, but there’s no guarantee that they will work (and I’m pretty sure no support). You would have to deal with different connectors (DB-9, RJ45) and different, incompatible voltages to power the CAN bus.

Tony

What is the big advantage to using an open standard such as CANOpen? In a word, interoperability. You should be able to mix and match CANOpen products from many different vendors. This has many benefits such as:

1. Reduced dependence on any one vendor. If a vendor goes bankrupt, stops making a product line, or increases its prices, it’s much easier to replace it with a similar product based on the same standard. For example, an AMC drive is not a drop in replacement for a Copley, but it’s a lot easier to swap them than, say, replace MEI PC/DSP motion controller with a Galil machine controller.
2. Much wider range of products available. For example, many proprietary distributed drive manufacturers do not sell I/O. Or they only sell low current or low voltage drives.

Of course, not everything is perfect. There are not CANOpen products for every need. Combining CANOpen products is not as easy it should be. I will write about specific examples later.

Tony

Well, it’s not all surplus, but most of the system was bought surplus. I will be writing about my experiences learning how to use CANOpen.

The lineup:

• Peak Systems PCAN-Dongle parallel port CAN interface
• GridConnect CAN-USB Adapter Light CAN interface
• AMC DX15C08 drives
• Wago 750 I/O system with 8 inputs, 16 outputs
• ESA COIA-XA Evaboard CANOpen I/O

Comment 4/7/2011: I have a lot more CANOpen equipment now; eventually I will get around to dissecting it.

Tony