Messages

61

General Mach Discussion / Re: Version 4

« on: October 13, 2012, 01:20:43 PM »

I was just looking over the new Keling website and I noticed he is offering something I found kind of odd. 

Mach4-Lite Licensed Software with Ethernet Smoothboard with screw terminals
http://www.automationtechnologiesinc.com/products-page/cnc-cam-software/mach4-lite-software-with-ethernet-smoothboard-with-screw-terminals

The wording sounds odd...  and there are no manuals available... 

62

General Mach Discussion / Dual Spindle Control - Companion Spindle

« on: September 29, 2012, 12:44:38 PM »

I'm working on a retrofit project converting an old early 1980s Hurco over to PC based control.  I've got the basic retrofit figured out with several things I need to nail down specific choices on yet, but "I want it all!"(I ran a servo on PC control a couple weeks ago, and I am nailing down the details on an air, spindle brake, and lubrication in my meager spare time.  Then I need to wire up permanenty all the stuff I tested before.)

The machine has a 5HP spindle motor with 3-120hz VFD control for speeds of 96 - 3600 RPM.  I woud like to be able to switch over to a "companion" spindle on the fly using offsets in my code to do detail work.  The reason companion is in quotes is I want full control of it as a fully swapped Z axis.  I'm not looking at clamping a router to the quill.   The companion spindle needs to be driven by a different VFD.  I have a 0-1000 hz VFD I'll program for 166 - 667 hz (10K-40K rpm) to drive that spindle motor.  

The companion spindle will be on its own linear rails with its own servo.  

I could use some direction here.  I need to be able to do two things.  

1.  Switch control between VFDs.
2.  Switch control between servos.

I'ld like to be able to do it in code, but I don't have an issue with adding hardware (relays maybe) to do it.  I have not written any macros for Mach, but if that will do what I want I'm willing to tackle that to.  

I was originally looking at just manually switching control or possibley writing two different machine profiles, but I noticed Syil Canda has a companion air spindle they claim they can switch back and forth to in code.  I know an air spindle is less complex to deal with than a VFD driven spindle, but still.  They are switching their Z axis, and they are changing from running their main variable speed spindle to opening and closing an air valve to run their air spindle.  

I've also been following Ger's design/build thread for his V2 dual spindle gantry router over on CNC Zone.  

The main power cabinet will be intersting to see if this works out the way I want.  It already has 2 VFDs in there, (the main spindle motor has a separate 3 phase cooling fan motor) and if the companion works out there will be three.  

63

General Mach Discussion / Re: Spindle Motor is the cause of all my problems

« on: August 11, 2012, 05:41:29 PM »

Perhaps there is some internal shielding that needs to be connected.  At the encoder end something would have to be connected to the body of the machine for it to be "grounded." I guess the easy way to tell is disconnected the controller end and put a meter on it between the shield and ground.  

I am not saying its impossible that they are creating a ground loop, just that its more likely they are connecting the shield to the device.

We may be quibbling over the difference between connected and grounded, but there is a difference.  On a device if there is a place to connect the shield or ground wire that does not mean its grounded at that point.  

64

General Mach Discussion / Re: Spindle Motor is the cause of all my problems

« on: August 11, 2012, 04:52:28 PM »

Not always true that grounding at one end is the way to go. For most things Mach related it is but I can assure you that only grounding the shield at one end of the encoder cable on the motors that utilise sick stegmann  sine/cosine smart encoders will not work, they need the shield grounded at both ends.
Hood

Then they are using the shield as part of the signal circuit or using an electrical charachteristic of the shield for some purpose other than just shielding if it actually must be "grounded" at both ends.  Alternatively they may require it be "connected" at both ends, but it might still only actually be grounded at one end.  Not being familiar with that particular piece of equipment of course you can argue the actual application more effectively than I could.  

An example I am more familiar with:
I know in fire alarm signal circuits often the shield must be connected through from device to device and often connected to the device (depending on the application), but its still only connected to ground at the control panel.  Accidental mechanical grounds are avoided by make the body of the device out of plastic.  

P.S. The main reason for the use of plastic is price.  Avoidance of accidental mechanical grounds is incidental. 

65

General Mach Discussion / Re: Spindle Motor is the cause of all my problems

« on: August 11, 2012, 02:04:31 PM »

Single end grounding of shields is the standard for most (all?) low voltage signals wires these days.  I have seen all kinds of weird things caused by ground loop when somebody mistakenly gets a second ground point.  Audible noise on audio cables.  Rolling bar distortion on video cables, etc etc ... 

Trust me.  Ground shields on only one end at a common central point. 

66

General Mach Discussion / Re: Backlash compensation

« on: August 10, 2012, 03:52:13 PM »

Well, Jeff, I might owe you an apology.  I dialed it down to mostly the bearings and the pin couplers.  When I installed my ACBs (with my own spacer so they worked like paired ACBs) I got it down pretty close to .001.  I was on the phone with Taig this morning over an issue with another part and I discovered something.  There is supposed to be a similar spacer between the skate bearings that Taig uses that was never installed on my machine that makes the skate bearings perform similarly to paired ACBs.  It was never there on any of my 3 axis. 

67

General Mach Discussion / Re: Version 4

« on: August 05, 2012, 01:21:59 PM »

Mach4 pre-Alpha Testing
http://www.machsupport.com/forum/index.php/board,90.0.html

Found this.  Didn't realize boards had been added so didn't look.  Last Comment July 14th.

68

General Mach Discussion / Re: USB vs PS2 (keyboard & mouse)

« on: August 01, 2012, 09:37:22 PM »

I was also wondering if it might be an issue with using a USB motion controller. 

69

General Mach Discussion / Re: USB vs PS2 (keyboard & mouse)

« on: August 01, 2012, 05:57:12 PM »

Total distance from PC to keyboard and trackball will be about 12' by wire.  There will be a bulkhead connector in line, and possibley a jumper/extension cable for distance.  

70

General Mach Discussion / USB vs PS2 (keyboard & mouse)

« on: August 01, 2012, 05:38:42 PM »

Any benefit to or negative for using one verses the other?  This is a dceision that doesn't have to be made right this instant, but I am starting to make some progress on my Hurco retrofit again, and its something I need to decide sooner rather than later.  I have a USB Smoostepper for the motion interface to the servo drivers, and everything else.  I was wondering if anybody had documented any issues or performance and stability issues with using the PS2 style interface for keyboard and mouse verse using the USB ports. 

The computer I plan for the big mill is a stable machine that has plenty of both types of ports.  It will get mounted inside one of the control cabinets, and have bulkhead connectors in the side of the cabinet for everything (monitor, thumb drive, etc) so I do need to do atleast some advance planning.