On 9/1/2012 11:51 AM, Viesturs Lācis wrote: > 2012/9/1 Dave<[email protected]>: > >> On 9/1/2012 3:02 AM, Viesturs Lācis wrote: >> >>> >>> So the missing piece of the puzzle is the means to control LinuxCNC >>> remotely. And as much as I can think of the required amount of >>> control, it is all there in emcrsh: >>> http://linuxcnc.org/docs/html/man/man1/emcrsh.1.html >>> >>> >>> >> This makes a lot of sense, but I would also look at using Modbus TCP and >> ladder, plus some custom M codes to interlock the machines together so >> you can prevent collisions between machines. >> Yes, it gets complicated but that is the nature of the beast. >> >> > How do You imagine custom M code can do that? > IMHO there should be some central piece of element, which checks > positions of all machines and then acts (for example, pauses one > machine), when it sees that collision is going to happen... > >
Custom M codes is just one tool in the toolbox that I thought would be useful. Those could be interjected in the G code to check for space ownership rights, take ownership and release ownership of the shared space or resource (set and reset semaphores). But I have no idea what physical arrangement these machines are actually in or how their operating envelopes overlap, so all I can do is generalize. For instance: Is there one or more resources that they all have to share, or are the machines in a series - ala a transfer line, such that one machine does an operation and then the part is transferred to the next machine. In that case one machine just needs to worry about what is going on with it's two adjacent machines and doesn't need to care about the other machines. That is the way that most of the transfer lines I have worked with function. There is logic between adjacent machines and then there is a supervisor system that loads Gcode and machine setups depending on the part being produced. I'd consider using Modbus TCP to get rid of hardwiring between the machines. The semaphore data could be shared between machines via Modbus TCP. I haven't actually tried it but I believe that LinuxCNC can host a Modbus client and a server at the same time. I think that using emcrsh would be fine to use as part of the supervisory system but I would not want to rely upon that to provide coordination between machines. Dave ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
