On 06/10/2014 06:52 PM, Trần Ngọc Quân wrote: > Hello all, > My previous question [1] is not clear. > > My idea is create hal drive (hal_serial) for pc com port: > PC <=COM=> Microcontrol board (MC51 for example) > > Protocol: > - PC read 8bits from Microcontrol boad, for read status of limit switch, > emergency stop button etc. > - PC write 8bits to Microcontrol boad, for on/off some things ( spindle, > pump etc.) > - Read/Write task will continue in forever loop. > > Step control by lpt or other. > > [1] http://sourceforge.net/p/emc/mailman/message/32442282/ >
The ModIO product does this: http://wiki.linuxcnc.org/cgi-bin/wiki.pl?ModIO Or this AVR example (bottom of page): http://wiki.linuxcnc.org/cgi-bin/wiki.pl?AVR http://wiki.linuxcnc.org/cgi-bin/wiki.pl?VFD_Modbus http://wiki.linuxcnc.org/cgi-bin/wiki.pl?ARM http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Emc2HardwareDesign Also note that the E-stop button circuit should be a simple wire loop that basically controls a power relay. If the loop is interrupted the power is cut. Smart bits like LinuxCNC and any controllers should have inputs that monitor the loop in order to act appropriately during an E-stop. The smart bits should not be relied upon to initiate an E-stop if an unsafe condition occurs. A watchdog signal may be used to monitor these smart bits and initiate an E-stop if any smart bits become dumb. There may be other important E-stop issues I have not covered here. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ ------------------------------------------------------------------------------ HPCC Systems Open Source Big Data Platform from LexisNexis Risk Solutions Find What Matters Most in Your Big Data with HPCC Systems Open Source. Fast. Scalable. Simple. Ideal for Dirty Data. Leverages Graph Analysis for Fast Processing & Easy Data Exploration http://p.sf.net/sfu/hpccsystems _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
