Hi everybody, I'm a new user of CAN, more specific CANopen protocol over CAN bus. I used to control six servomotors in a robot. I selected this option because the other were:
- Analog output (no flexibility for my requirements). - RS232 (slow if compared with CAN maximun velocity of 1Mbps). - Other buses (increased cost). Because of support, I purchased six Maxon Motors EPOS 24/1 servocontrollers with CAN open, this allowed me to control the motors in three operating modes: - Velocity Mode. - Position Mode. - Current Mode. My final configuration was: - A PC104 with QNX operating system (real time OS). - A PC104 CAN card. - Porting a Linux CAN driver to QNX. - Porting some parts of CANfestival CAN open layer to QNX. - Six CAN open servocontrollers. I hope this will help you. Eugenio. On Sun, 2009-02-08 at 10:42 +0100, Peter blodow wrote: > Hello gentlemen, > > having spent a lot of years as a facility manager with experience in > machine control technology I'm trying to bring light into this guessworking. > > The CAN-Bus (Controller Area Network) has been developed by Bosch being the > largest supplier of automotive parts in the world and Intel being the most > potent chip producer. They both wanted to set a standard in order to > prevent wild diversification of the market. > > Besides in cars it is also used in medicine technology, fabric production, > and general machine automation, anywhere, in order to act and react very > fast by means of very short messages (8 Bytes). It is actually a serial > multimaster protocol (field bus) and is topologically transported by RS 485 > (screened twisted pair cable, Cat5 or better). It is standardized as ISO > 11989 since about 1990. > > There can be as many as 255 participants (computers, actors, sensors) on > the bus, date rate ranges from 50kBit/s to max. 1 MBit/s. Wire lenght > ranges from 800 to 40 m, correspondingly. > > There is a user group called "CAN in Automation" (CiA) founded in 1992. > Network access is similar to CSMA/CD. All connected subsystems may work > indepentently. They have no addresses. In data transmission the telegrams > bear an identifier describing the kind of value transmitted, e.g. a > temperature number, and defining its priority. This is different from other > bus systems like IEEE (HP-bus) where stations are addressed by a telegram > prefix. As soon as one CAN chip starts transmitting al others are switched > to listeners. The listeners read the telegram and decide if it is relevant > to them or not. > > The maximum date speed is guaranteed only for telegrams with maximum > priority. For all other signals no transmission rate can be predicted, > therefore the CAN bus is not applicable for real time purposes. > > I hope to have helped to clarify the issue. > Peter Blodow > > > ------------------------------------------------------------------------------ > Create and Deploy Rich Internet Apps outside the browser with Adobe(R)AIR(TM) > software. With Adobe AIR, Ajax developers can use existing skills and code to > build responsive, highly engaging applications that combine the power of local > resources and data with the reach of the web. Download the Adobe AIR SDK and > Ajax docs to start building applications today-http://p.sf.net/sfu/adobe-com > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Create and Deploy Rich Internet Apps outside the browser with Adobe(R)AIR(TM) software. With Adobe AIR, Ajax developers can use existing skills and code to build responsive, highly engaging applications that combine the power of local resources and data with the reach of the web. Download the Adobe AIR SDK and Ajax docs to start building applications today-http://p.sf.net/sfu/adobe-com _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
