One of the reasons I am asking is that my Electronic Lead Screw controller has a spot for a CAN bus driver. Years ago I ported the Microchip CANopen stack to it and had it serve as a minimal keypad/display and MPG encoder. I also built a small expansion board for the ELS that can stand on its own if I put in a processor. I also ported the CANopen stack to that board and have had it as a CAnopen device that responds to SDO and PDO messages. It has 4 relays, 4 opto inputs and some voltage/current measuring capabilities. So I have the infrastructure to run stuff.
I started working with CAN bus in 1992 so the idea of expanding a PC using a simple USB to CAN dongle for tool changer and other controls is really attractive to me. With CANopen or what one might call almost a minimalist CANopen one could add simple robot arms to place and remove parts to be machined. None of this requires Ethernet or centralized control. Often it's as simple as READY/REQUEST/BUSY/AVAILABLE/ERROR handshaking that used to be done with wires in the PLC days. The device sits in ready, gets a request and sends back a busy to acknowledge the command. Once the command is complete it sends an available or an error. I'm a big fan of modularizing things so that they can be tested in a standalone fashion. But how to turn an M code into a CANopen message is, at the moment, beyond me. John > -----Original Message----- > From: Nicklas Karlsson [mailto:[email protected]] > Sent: February-24-18 1:10 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] CANopen over Ethernet CiA 309 --> Ethercat seems > to work > > > But if 99% of the devices out there are physical CAN bus based and there is > > already a CANopen driver for Linux, is the interface to CANopen > transparent > > for both systems? > > CiA309 should be transparent for both systems but are probably of less use > for an ordinary CAN bus but to access the hardware bus some extra > hardware is required. > > It seems I got SDO communication up and running via Ethercat according to > CiA 309 but I have not yet tested write access only read. > > > What I mean, and I may not be clear on this, is if the LinuxCNC has the > > capability of being a CANopen Master then how do you see your code > handling > > both bus architectures? Or should it? > > It is an Ethercat master but messages sent follow CANopen. > > > ... > > From the G-Code (M07) perspective the Pump On results in the periodic > PDO > > 0x287 to have Bit 3 in Byte 1 set. An M09 would turn off both mist and > > flood so Bits 2 and 3 would be cleared. The PDO message could be > periodic > > or periodic and on change of state for faster response. > > Periodic I consider good in a real system and it also have the advantage > broken cable could be handled. > > > So I guess I'm asking how does an M07 become either (or both) an Ethercat > > CANopen message and/or a physical CAN bus CANopen message? > > In the Ethercat master I added hal pins, some are bits connected to a bit in > sent messages. This configuration should ideally be possible to do in > configuration file and templates for standard communication profiles would > certainly be useful if available. > > I found the simple_test program in soem lack a gnu GPL copyright notice and > are waiting for confirmation E-mail from github before I could upload. > > > Regards Nicklas Karlsson > > ---------------------------------------------------------------------------- -- > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
