Messages

861

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: April 09, 2010, 05:14:29 PM »

Hood, every time you speak, I realize how much I have to learn 

I am aware of differential signaling being used for encoders (I use that myself), but are you saying that your servo drives also use differential step and direction signals? Does smoothstepper support differential step and dir signals?

My board does not really 'accept' anything, it is just a signal switcher.  It would not have enough lines for differntial signals, but I suppose you could use two of them. I don't think I would be inclined to pursue that unless your setup is common. I have not heard of using differential signals for step and dir. What would be the purpose except to mount the drives far away from the BOB?

862

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: April 09, 2010, 04:31:10 PM »

Update on the swapaxis question: the third of my little PCB projects is now complete and tested . . .

The new 'SWAPAXIS' hardware board is completed and working!

This should work with any CNC software and also with the Smoothstepper. The rehoming macro still works, but the swapaxis command is now superfluous, of course and will be removed.

I extend an offer to Hood, who has helped me a lot with my projects, to receive a free swapaxis board to keep in exchange for testing it with smoothstepper. If Hood declines then the offer is open to anyone with a smoothstepper who is willing to do some testing.

I am currently accomplishing the axis swap via the M9 command for flood cooling. I have the output mapped to the SwapAxis board. ANY output will work fine, I just used a 'standard' CNC output that every system should have available.

Photos of the little PC board follow. The .032" end mill I normally use was too wide for the very small traces needed for this little guy, so I did my first rounting with a 30 degree router bit to cut the traces. NOw I have 'ebgraver fever' and I want to engrave everything. Trying to figure out how to fixture the dog . . LOL!!

863

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: March 22, 2010, 01:21:11 PM »

As an example, my macros at issue are the following. I have posted the macros previously, but if you can't find them, I'll be happy to post them again. Note that the numbers are not special, you can use any unreserved number you want:

M951 initiate swap axis (A axis becomes Spindle and Spindle becomes A axis)
M950 Cancel swap axis and re-home the A axis

M961 apply spinfle lock (just activates an output that I have controling a relay which in turn controls a solenoid valve which in turn operates the air cylinder)
M960 release spindle lock

Example of G-code would look like this (Note that 'M' codes call external macros):
N50 M951 (initiate swap axis)
N55 M3 (turn on spidnle)
<add your turning code here>
N65 M5 (turn off spindle)
N70 M950 (un-swapaxis and re-home A axis - note that the A axis has lost its reference due to being a spindle, so re-home puts it back to a known zero)
N75 G0 A45
N80 M961 (engage spindle lock)
<cut a tooth, drill a hole whatever>
N150 M960 (release spindle)
N155 G4 P.1 (delay *might* be needed depending on how fast the lock is vs your accell of the A axis)
N160 G0 A90
N165 M961 (engage spindle lock)

etc, etc

864

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: March 22, 2010, 08:02:25 AM »

whatda: My 4th axis is being made into a standard part of a larger new machine being devoloped now. For that project, I am developing a hardware 'swapaxis' that will work outside Mach so that my 4th axis is not tied to using Mach. There are also other people who want the 4th axis and do not use Mach3. That may do the trick for you.

Also I am deveoping a 'Super Duty' version of the 4th axis which has a 'back gear' double reduction belt setup for heavy simultaneousl 4 axis milling and for high toque applications like drilling large diameter holes in the center of tough material or turning large diameter stock. The high speed capability remains and switching between the two is a simple belt move. You may be able to do something similar, but swap motors instead of reduction sets. I'll be posting videos soon on Youtube when the new 4th axis is finished so you can see how it is set up.



stnc: What is it exactly that you want to know how to do? The swapaxis function is part of Mach3 and is not done in g-code. I wrote a pair of macros to call it. You call the macros from G-code using the 'M' command. It that what you are after?




             

865

General Mach Discussion / Re: Question for anyone with 'enable/disable' capable servo drives

« on: March 18, 2010, 12:06:30 PM »

If you are using a drive as an indexing drive for something like a tool turret or spindle orientation then if disabled and moved the drive will keep a not of the encoder and when you command a further index it will move to the correct position but not until a move has been commanded. Or at least that is my experience from my drives.
Hood

Spunk: you are more or less correct in your intepretation of the question. Hood has provided a partial answer for at least one behavior.

Mach is irrelevant, I think, for the very reason correctly pointed out by KTM, i.e. open loop operation. With a true closed loop setup, there is no issue, I would think.

If my understanding is correct, Mach only output's pulses, not positions, so it it up to the drive to determine and maintain the current absolute coordinate.

If you try to move an active servo drive, it sees the encoder moving and applies power to move back to where it thinks it should be . . by reducing the error. In the case of a drive which is 'disabled' (i.e. no motor power) and yet continuing to track the encoder, this error could become great. The concern in implimenting such a feature in an open loop system like Mach is the behavior to expect when the drive powers up and does what it does; which is to reduce the following error to zero, which as Hood pointed out could be a good thing or a bad thing depending on the situation.

So far we have Hood's drive keeping track of the error, but not acting on that error when re-enabled until new pulses are recieved form the CNC. This seems like a sensible solution. Alternately, if the drive does an immediate full power move reduce the error to zero, it could be nasty.

So are there any other behavior that anyone can share? Some drives fault and continue to track the encoder also. So if it knows it has been moved during a fault or while disabled, the reponse to being re-started (but not reset) would be whatever the firmware says to do. I have no experience with drives that have this capability, hence the question. 

866

General Mach Discussion / Question for anyone with 'enable/disable' capable servo drives

« on: March 18, 2010, 03:44:35 AM »

A couple of guys on here said they have servo drives with an 'enable' pin that kills the power side of the drive and yet keeps on tracking the encoder.

My question is; what does the drive do when it is re-enabled after a disable if the axis was moved during the disable?

If the axis was moved, does the drive consider the new position to be OK, or does it try to immediately return the axis to the pre-disable position?

867

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: March 14, 2010, 08:00:48 AM »

Simply use Mach's 'spindle' to run the 4th axis and just operate the router off a manual switch (or via a relay if you want CNC control).

868

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: March 13, 2010, 03:01:39 AM »

You can run a router and use the 4th axis in 'lathe' mode now unless you want to use Mach to control the router speed.

This project is alive and moving forward. The current 4th axis version will become a standard part of a new commercial machine and I am currently building a new 'Super Duty' version with double reduction and a robust steel disk brake. I am pursuing a couple of different options for controlling the spindle without using the swapaxis function.

One possibility is a solid state device which will switch the servo motor's controller from a servo drive to a speed controller.

The second involves another modification of an existing servo drive to perform the speed control function internally and outside of Mach, but using an output of Mach to engage the 'lathe' mode.

A third is to use a pulse generator to create the pulse stream for 'lathe' mode and only switch the encoder output between Mach and the pulse generator for 'indexer' mode and 'lathe' mode respsectively.

There are advantages and challenges with each method.  It is an interesting challenge  Anyone who wishes to share some creative ideas on this challenge is certainly welcome to do so.

869

General Mach Discussion / Re: USB and Mach

« on: February 18, 2010, 07:13:01 AM »

Does the smoothstepper support swapaxis yet?

870

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: January 27, 2010, 12:38:41 PM »

Hood: If we may refer to the drives that I reviewed as 'hobby level', then there are none that can have their amp output commanded in real time with Mach3 software. I'm not saying it is impossible, as there may be some method that I am not aware of, but I did investigate 'real time' reconfiguration via Mach3 at the time of the review and I know of none. CNCdrives is adding the capability and I don't know yet exactly how it will be implemented, but it will thru a macro for sure and will use  the currently unused 'aux' connector on the drive. . 

If this is with reference to my last post then I was meaning disable the drives, I would imagine most servo drives require an enable signal, but maybe not?
Hood

Some can be stopped with an external signal, but if I remember correctly, restarting any of them requires a reset and they loose reference. None of them track the encoder during a fault, so even if you could restart them, results would be unpredictable. methinks.

If I recall correctly, you have high end stuff and it may have a more sophisticated capability in this regard. I do know that some drives continue to track the encoder even when they are faulted . . . totally logical . . . and totally missing from the low end. Of the hobby level drives I tested, only the CNCdrive product was acceptable and it can be stopped, but must be reset to start up again. Unlike others, at least the CNCdrive products can be reset without powering down the whole system and waiting for all the CAPs to bleed off.