Topics

1

Galil / Homing without switches

« on: October 31, 2010, 10:08:45 AM »

My old Dynapth control used marks and the encoder index pulse for homing on the X & Y axes, no homing switches.  I would like to use a similar approach with Mach/Galil.  I would like to zero at the mark, have the axis go .1" or so negative, reverse positive to the encoder index.  I tried simulating the home input with a brain (activating at -.100).  It shows to be working on the diagnostic screen, but will not reverse the axis when referencing like it should.  I suspect that the homing process is internal to the Galil, so it doesn't care what Mach sees, but I would like to know if there is a way around this.

Thanks,
Mike

2

Galil / Physical override pots with Galil

« on: September 01, 2010, 11:32:57 PM »

I would like to keep most of the physical controls from my Dynapath control (cycle start, feed hold, E-stop, feed rate override, spindle speed override).  I think I can handle the first three, but I'm not sure about the override pots.  Would I wire the wiper to an analog in on the Galil and write a brain for Mach, or is there a better way?  I though about just doing the spindle speed override with a Galil program, but I don't think this would work for feed rate.

Mike

3

Galil / Galil 2280 issue

« on: August 16, 2010, 09:41:47 AM »

I am in the middle of converting an old Dynapath System 10 control to Mach 3 with a Galil 2280.  The machine is an early 80's vintage 3-axis machining center with Servo Dynamics 1525 analog servo drives and SEM DC brush servo motors. 

I started with the Z-axis.  It works fine through Mach and Galil interfaces, runs G-code, no issues.  The Y-axis encoder went bad, so I am waiting on a new one.  On to the X-axis and I have a drift that I can't figure out.  The motor always wants to run about 30 rpm in one direction.  It will respond to jog commands in either direction, but will resume the drift after the jog.  It does not increment the DRO or change the Galil position when it is 'drifting'.  If you look at the TP and TE data on SmartTerm, it has a position error that bounces around from maybe 10-50 counts.  The 'actual' position is always less than the commanded postion. 

It acts like it loses encoder feedback as it nears the commanded position.  I can command a 100000 count move and it will end up bouncing between 99950 and 99990, with the servo running about 30 rpm and no more encoder counts being recorded.  If I kill the servo power and turn the screw manually, the encoder appears to be working perfectly.   According to SmartTerm, all axes are are set up at KP=6, KD=64, KI=0.  I did try increasing KD and adding in some KI, but neither has an effect on the drift.  The servo drive itself is balanced.  If I remove the Galil signal the motor is stable.

Any thoughts?

Thanks,
Mike

4

Galil / Spindle speed control w/2280 & VFD

« on: January 03, 2010, 04:04:25 PM »

I have read the post below on spindle control and I am confused as to how this is supposed to work.  I have a 2280 card, Mach R3.042.029, and Galil plug-in 4.4.0.0.  I am using a Yaskawa VFD for the spindle. It is a vector drive, but I am currently just using it in 'dumb' mode. If I recall, I can either run this -10V to 10V or 0 to 10V and use the forward/reverse inputs on the VFD for direction.  The machine is already wired for the second case, so it would be my first choice.

I will limit the drive to 120Hz and would like to configure it so that 120Hz = a 10V input.  The machine currently has step pulleys, so I would need to use the pulley ratios to calculate the correct motor speed.  As an example, lets say I'm using a 2:1 speed up drive and command an S5400.  This would be 2700 rpm at the motor (90Hz) and voltage out should be 7.5V (10*90/120).  Any way to do this?

If I can't do it with the above hardware, can I do it if I add a spindle encoder?

Thanks,
Mike
  

5

General Mach Discussion / Tool changer questions

« on: October 30, 2009, 11:34:57 PM »

I am converting a mid-sized mill from an old Dynapath System 10 to Mach with a Galil 2200 board.  I have a pretty good idea of how to do everything except the tool changer.  It has a 12 tool carousel with an arm. Currently, it uses an old Omron PLC to handle the M functions and tool change.  Communication between the Dynapath and PLC is basically a parallel interface using the CNC outs to PLC inputs. It uses six lines for data (tool or M number), one line to signal an M code, and an final line to signal a tool number.  I have a Siemens S7/200 PLC that I have pretty much duplicated the Omron programming on, so I'm not worried about having to buy a PLC or software.  The PLC is fairly complex with 22 ins and 16 outs.  As I see it, my options are:

1) Emulate the current setup by writing some VB code to duplicate the current interface (should be fairly easy, but kind of a crude method)

2) Keep the PLC functions the same, but communicate with the PLC over Modbus (I am not fluent in Modbus, is it worth the trouble?)

3) Drop the PLC and do all of the tool changer functions in Mach using the extra IO on the Galil (one less programming langauge to mess with)

Any thoughts?

Mike