Excellent reply John, thank you for taking the time Andy John Kasunich wrote: > Andy Holcomb wrote: > >> How would I implement this? To be more specific which pin on the LPT >> port would I attach the wire to? >> > > Any pin that is an input and isn't already in use. > > >> Would I need to have the other leg of >> the switch tied to ground or 5 volts? >> > > EIther one. If you tie the other end of the switch to +5, then > closing the switch will pull the parport pin high. You need > something else to pull it low when the switch is open. If you tie > the other end of the switch to ground, then closing it will pull > the parport pin low. Since A) many parports already have pullups, > and B) there isn't a convenient source of +5 on the parport, its > usually easier to hook a switch between the parport pin and ground. > > The above is NOT an EMC specific issue. How to hook a button to a > parport is basic fundamental knowledge for using a PC to control > anything. This information is on the web - for example > http://www.epanorama.net/circuits/parallel_output.html > Inputs are addressed in the section "Input Circuits" about 3/4 of > the way down the page. Electrically, connecting a pushbutton or > toggle switch is no different than connecting a limit or home switch. > > >> In which config file will I need >> to set this up >> > > In your HAL file. You have a choice - you can add custom HAL > stuff to your existing file (I assume that is a copy of one of > the sample configs) or you can put your stuff in another file > and invoke it from the ini file. > > >> and how would I do that? >> > > Lots of possibilities. You could get fancy and use classicladder > to make a latching pushbutton (push button A to pause, button B > to resume). You could do the same thing with the HAL flipflop > component (simpler - see "man flipflop"). You could use a toggle > switch instead of a pushbutton - that means no latching is needed > at all. > > A couple of detailed examples: > > 1) You are using a toggle switch, and wired it to pin 10 of the > parport. The switch is wired from pin 10 to ground, then when > you flip it ON, pin 10 goes low. Add this to your hal file: > > # when external PAUSE switch is on (input low), pause the > # machine using feedhold input > net feedhold parport.0.pin-10-in-not motion.feed-hold > > 2) You have two buttons. PAUSE is connected to parport pin 10, > and RESUME is connected to parport pin 11. Both are active low > (pressing the button makes the pin on the parport go low). > Use a flipflop to do the latching: > > # need a flip-flop to latch the state of feedhold > loadrt flipflop count=1 > addf flipflop.0 servo-thread > # connect the flipflop output to the motion controller > # so motion will stop when the flipflop is set TRUE > net feedhold flipflop.0.out motion.feed-hold > # the PAUSE button should set the flipflop > net pause-button parport.0.pin-10-in-not flipflop.0.set > # and the RESUME button should reset it > net resume-button parport.0.pin-11-in-not flipflop.0.reset > > I sincerely hope you do NOT just copy these examples and > use them. To get the most out of EMC and HAL, you should > understand what it is doing. The HAL code above is not very > complicated, and it is commented. If you read it and > understand it, you have taken the first step from "machine > user" to "machine builder". If you aren't willing to take > that step, then you are stuck using the stock configuration. > > The EMC2 Integrator Manual is the "bible" for machine builders. > http://www.linuxcnc.org/docs/2.1/EMC2_Integrator_Manual.pdf > > Regards, > > John Kasunich > > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > >
------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
