CanOpen DSP-402

Greetings all,

I'm trying to find some information on CanOpen Standard 402, specifically how a drive equipped with it might be used.

Searching the web, all I've found has been extreme nuts-and-bolts information about PDOs and SDOs, or books on how to build your own product. I'm actually looking for something more general...

Suppose my PLC says "Now supporting CiA 402!", and my servo says "CiA 402 Compliant!". When I plug them both in - what?

Do I get some spiffy registers or functions blocks that let me start positioning the drive with minimal effort? Or does it just mean they have some special CanOpen extensions that I still have to construct and implement myself that same as 301?

Any info would be helpful.

Thanks!

TM

Hi Tim,

Unfortunately in the US it seems that CanOpen standards are the Wild West of communication buses . The only thing that seems standard about the implementations is the name CanOpen. After that you must tread softly. I believe this is mostly because there is no certifying entity like ODVA or PI. Everyone makes their own rules so there are as many rules as there are manufacturers.

I have worked with I/O, position transducers and servos on CanOpen. The first two were relatively simple but the servo was more of a challenge. This particular device was a brushless DC servo motor with a built in controller. It supposedly supported 402 but with every device there can also be "manufacturer specific" inerfaces and they had definately worked out that part of the product more than the "standard" 402 portion of the control.

There also seem to be a myriad of ways to set these networks up unlike DeviceNET which pretty much uses RSNetworx. Some devices have their own software to set up the network, Some come pre-configured and others can let the master set them up at power up. Or there can be a combination of all of these adn more.

In the CoDeSys programming software it can be very easy to set up a CanOpen network if you have a good EDS file. I haven't seen many good EDS files .

That said, I still like the idea of CanOPEN. It is extremely flexible and powerful. The application standards look good so maybe it will take off more in the future.

What type of drives are you talking about. Maybe someone here will have had experience with them...

AC Tech 940 PositionServos. Good drives, very versatile, and I'm proud to say I've had a hand in debugging some of their 301 stuff [] That said, I am interested in 402 and the idea of fly-by-wire, but haven't found anything about how it works from the perspective of an end-user. Trio Motion claims to have a wizard for setting up such things (and cautions that different drives have different levels of success) but their documentation is simply non-existent. If they didn't mention it on the website, you wouldn't know it existed...

Thanks!

TM

CanOpen is an absolute pain for the reasons mentioned unfortunately. EDS files are unreliable and varied. I do not know if the EDS files that have been tested by ODVA for Device Net would help you or not. The uncertified ones are always a pain with Device Net too.
It is better if there is a protocol embedded such as J1934 that is being used by most of the generator manufacturers and generator controller people such as Woodward. It is fairly controlled and usually what you expect is what you get.