On Monday, November 14, 2011 11:47:08 PM Kirk Wallace did opine: > On Mon, 2011-11-14 at 18:41 -0800, Chris Reynolds wrote: > > So I've been running my mini-mill with EMC2 now for almost 2 years, > > and I've gotten to where I'm interested in having the spindle > > controlled by EMC2, as well as possibly a tool changer. So I started > > reading the wiki about spindle control, and I've been reading through > > the HAL manual, and quite honestly I feel dumb. > > > > > > There are so many things that I don't get, like > > > > do I need to ditch the motor controller that's in the mini-mill and > > replace it with an H-Bridge? Or do I somehow tie EMC2 into the > > existing motor controller circuit board? etc etc. > > What kind of spindle motor and controller do you have? Most mini-mills > have a DC motor that runs at 90 Volts DC. The controller is usually an > SCR type: > http://www.wallacecompany.com/machine_shop/kbic/ > Look at that 'scr' a little closer Peter and look up its part number. I don't think its an scr. At least in my micromill, it is a power hexfet, being switched on and off at about 20 kilohertz.
> with a potentiometer that sets the speed (see bottom right of above > link). The motor usually is driven in one direction or has a manual > switch or other means to get the spindle to run in reverse when needed. > > EMC2 can be used by replacing the potentiometer with an opto-coupler and > a PWM signal. The opto-coupler mimics the potentiometer by turning on > for a short time then off for a short time. The ratio between ON time > and OFF time sets the speed. EMC2 is then set up using HAL components to > connect the HAL spindle speed pin to a pwmgen component and parport. > This will control the speed but not the direction. An H-bridge or a > relay could be used on the SCR controller output to switch the motor > wires to make it turn forward or reverse. The HAL spindle direction pin > could be connected to parport pins then to the bridge input pins. SCR > speed controllers don't like the output switched while the output is on, > so the direction should _not_ be changed while the motor is being > driven. > > > I don't get why I'm having so much trouble getting my head around > > > > this stuff. And I haven't even begun to look into what it would take > > to control an automatic tool changer. The more I read the more > > confused I get. hahaha > > > > > > Chris > > The key to EMC2's tool change is the iocontrol.0.tool-prepare and > iocontrol.0.tool-change connections in your .hal file. The standard > setup is: > " > # create signals for tool loading loopback > net tool-prep-loop iocontrol.0.tool-prepare iocontrol.0.tool-prepared > net tool-change-loop iocontrol.0.tool-change iocontrol.0.tool-changed > " > > This "short circuits" the signals so that when a g-code Tx is invoked, > to prepare a tool for a change, the request immediately trips the > prepared input which tells EMC2 the tool is prepare is done. When an M6 > g-code is invoked to start a tool change, this signal is also routed > into tool-changed to signal the change is finished. This is set up this > way for machines that don't have tool changers, so that the the g-code > program will keep running if Tx or M6 is in the program. For machines > with changers the short circuit is disconnected and the signals routed > to component pins that invoke software or hardware that does the prepare > and change. Here is my part of my lathe setup: > " > ### TURRET ### > # create signals for tool loading loopback > linkpp iocontrol.0.tool-prepare iocontrol.0.tool-prepared > linkpp iocontrol.0.tool-change turret.0.position-change > linkpp turret.0.position-changed iocontrol.0.tool-changed > > " > > Prepare is still "shorted" because there is nothing my lathe can do to > prepare for a change. The change signal is routed to a pin on my turret > component. When the turret is done changing and is parked, a signal is > returned to iocontrol to tell EMC2 the change is done. If and how you > need to connect the prepare and change signals depends on the kind of > changer you have and what will control the prepare and change > mechanisms. I wrote a HAL component using C to control my turret, others > have used Classic Ladder, or you could use an external PLC or > micro-controller. > > There are a lot of details I haven't covered but this should get you > started. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> Q: What's the difference between Windows 95 and a highly destructive virus? A: About 300 MB of hard disk space. ------------------------------------------------------------------------------ RSA(R) Conference 2012 Save $700 by Nov 18 Register now http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
