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Topics - rustyolddog

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1
VB and the development of wizards / Programming question
« on: August 20, 2016, 12:08:52 PM »
I've been a long time licensed Mach3 user. I recently ran into an application where I need control from a piece of software but without the Mach GUI. I'm wanting to use my USB SmootherSteeper to drive the motion control board. The software I'll be using hands off the motion commands in the form of .bat files to the motion control software, waits for the motion to be complete then continues. Is there a way to accomplish this with Mach? I primarily need to operate a rotary axis.

The manual for the software I'm referring to can be found here page 99 (5-98) the section on the PLUS version

http://cdn2.hubspot.net/hub/68377/file-15229185-pdf/docs/prolase7_manual.pdf


My question to them was: Are there any alternatives to using Indexer LPT & a LPT  port? Specifically something USB?

Their reply:
Yes, most of my OEM customers have set up other control methods, many using USB indexers.  This way of control cost a lot more money than LPT Indexer.  American LaserWare dosnt get involved with that end of a system, the integrator handles that.  ProLase provides a general interface in which ProLase will call an external program (written by the integrator) and pass this program the name of each axis and the position ProLase wants each axis to go to.  The external program takes this axis ID and position information and forms movement commands in the language of the specific controller and sends those commands over the USB port.  The external program then checks the status of the indexer until all axis are finished moving, then quits, which returns control to ProLase.  After ProLase calls the external program it simply waits until the program finishes before continuing.  ProLase will call this program every time it wants to move one or more axis.  This general interface can be used to control almost any kind of motion control system including stepper and servo. Usually this program can be written very quickly (its quite simple, sometimes just a BAT file) and for a relatively low cost.  The reason we do it this way is because there are hundreds of control systems, all having there own command set.  Some call the Axis XYZ, some ABC, and others 123.  Some use commands like MOVE, FEED, GOTO and others use "G" codes.  We don't want to write drivers for hundreds of different controllers, this general interface will work with all of them.


2
Going to do a clean install on a new old computer, no i'net access or network. Dedicated to Mach 3 only. Should I use the original pre service pack XP which is fast & unbloated or should I go to SP3 and install all the latest updates? It's a P4 2gHz 2GB RAM

3
General Mach Discussion / DRO glass scales and Mach
« on: April 29, 2014, 10:29:40 PM »
Is there any way to feed the quadrature  output of the typical DRO scale into a BOB or similar interface so that it can be used as an absolute encoder for Mach? I would presume it would be possible since servos use an encoder.

4
My old HP laptop running mach2 died and I had to set up a newer, faster Compac EVO 610c and Mach 3 Win XP. The last time I ran it, it seemed fine. Today when I went to jog it upon start up, the motors would stall and miss steps. Ran the driver test and it bounced between pulsing too fast & normal, I tried disabling various unused hardware items like the IR port etc. Uninstalling software, etc. no luck. Installed the various drivers related to the laptop & uninstalled them.

 All this at 25kHz kernal speed. On a whim I tried selecting the different kernal speeds during the driver test and as I increased, the display smoothed out an stabilized  for all but the top kernal speed. I went back to Mach and changed the kernal speed in the setup and it seems to jog just fine now but I don't want to risk a crash or stall.  Anyone have any insight into this issue? I seem to recall having the problem initially upon installing Mach 3 but when I installed the sound card driver, everything worked. It's not an issue with the printer port voltage, I drive a breakout card with it to get proper port levels to the controller. Help!

5
Feature Requests / Interrupt Button Please
« on: February 12, 2014, 04:02:57 PM »
I haven't had a chance to search the board in depth to see if this feature is already available. On my big machine, a Hurco VM1, I have a Interrupt button on the console. When pushed while the machine is running, it stops running code, shuts down the spindle, turns off the coolant and retracts the Z axis. It allows you to stop in the middle of a job, clear chips, inspect the finish, whatever you need to do. When you're done, you hit Auto and it resumes where it left off. When running Mach and had to interrupt it, I hit Pause on a Z retract, jog out of the way etc. 

6
SmoothStepper USB / Question about Smoothstepper
« on: May 13, 2008, 03:26:13 PM »
I use a HobbyCNC controllers to run my benchtop machines from a laptop, what kind or type of performance improvement could I expect to see? I'm guessing that since one machine is a mill with a 4th axis, and I have a CNC lathe, I could use one laptop to drive both machine controllers since it will control up to 6 axis, correct?

7
Setting up an new computer so I can upgrade from Mach 2 to Mach 3.

Using the stock screen set. Where is the step jog feature? I'd like to be able to jog in increments and toggle between continious jog & step as I do in Mach 2.

I'm getting a weird grunt/resonance when the motor changes direction. It's fine jogging in the same direction.

8
General Mach Discussion / Macro or wizard for incrementing number?
« on: March 13, 2008, 11:40:07 AM »
I was wondering if there was any way to create in Mach a macro or canned cycle or wizard to generate an incremental lot or serial number to be engraved on a part as a machining cycle is completed. There is some dedicated software capable of doing it, 2Linc, CNCWrite, Millwrite but these would not interface with the normal CAD/CAM software. I know Haas has a canned cycle capable of doing it. Suggestions, solutions?

9
ETA: See the post on page 2 which is the final draft of the exercise.





I've spent a good bit of time perfecting my 4th  axis and I thought I'd share what I learned with others here. The problem/question is at the end.

Under normal circumstances, the 4th  or 'A' axis is angular and the moves are called out in degrees. If you have a CAD/CAM software that supports a 4th  axis, you are in good shape. If all you have is a 2.5D CAD/CAM, then things can be a bit more challenging.

First, lets address the 4th  axis mechanics. My and most other 4th  axis 'conversions' involve adding a stepper motor to a rotary table. Simple enough. In my case my rotary table was a 1:72 ratio. 72 turns of the worm results in one 360 degree rotation of the table.

My stepper motor is a 200 step per revolution (1.8 deg) per step (360 deg/200 steps=1.8deg/step) My controller runs 1/8 microstep mode so it takes 1600 step pulses (8*200) to make a complete 360 degree motor rotation.

72 motor rotations makes one rotation of the rotary table so 1600*72 means 115,200 steps for one rotation of the rotary table.

If we divide 360 degrees by 115200, we get .003125 degrees per step.

Alternately, we can calculate the number of degrees required to move a linear distance around the circumference of a part.

For example: We have a part that is 1.5” in diameter. 1.5* Pi (3.1415) gives us a circumference of 4.7123” If we divide 4.7123 by 360 we get .01309 inches of  linear movement per degree.

If we want to move a linear distance of 1.125” on our 1.5” diameter (4.7123" cir) part, we divide 1.125” by .01309 in/deg and get 85.94 degrees of movement required to move 1.125” linear on the 1.5” diameter part.

Thus, we can create a correction factor or scaling factor for our 4th axis by dividing the circumference of the part by 360, and manually coding the linear distance for the ‘A’ axis move.

Alternately, if your CAD/CAM software has a scaling feature, you can create a scaling correction factor. You would create your part in standard 2.5D with X & Y moves with Y typically being the axis to be converted to ‘A’.  You take the circumference and divide it by 360 then take the inverse of that value (1/x) and that becomes your scaling correction factor.

Using the previous example: 1.5”* 3.1415= 4.7123”
4.7123”/360=.01309
1 divided by 0.01309=76.397 scaling correction factor
 
Therefore, you would scale your ‘Y’ axis by a factor of 76.397 to get the equivalent linear move on the ‘A’ axis. Once you post the scaled code, you would do a simple search & replace substituting ‘A’ for ‘Y’ in your text editor. The end result  X, Y, backplot & drawing will look strange because the Y axis will be substantially elongated. But it will be correct as far as the computer is concerend.

While it does work, this later method has an inherent problem. The feed rate will be significantly slower than the desired or specified feed rate.

As a result, I had to search for a better method. Thus part 2.

Using the same math:
72:1 ratio, 1600 steps per rev of the motor, 115200 steps for 360 rotary table movement .

In Mach2 (my version), we can take the total number of steps for 360 deg. Table rotation and divide it by the circumference to determine the number of steps per inch of movement. Again using the previous example:

1.5” diameter*3.1415=4.7123”
115200/4.7123=24447 steps per inch of linear movement.

In Mach, we change our A axis from angular to linear. Then calculating for the diameter of the part, we take the solution and use it in the ‘Steps per Unit’ setting for the ‘A’ axis in the motor tuning menu. We do this for each different diameter of part that we have machine. For a 1.5” diameter, we enter 24447 for our steps per unit.

Thus, by doing so we do NOT have to scale our ‘Y’ axis by a calculated scaling correction factor. Our backplot & drawing appears normally. We still have to do a search & replace substituting the A for the Y axis in our posted code. And the beauty of it is the specified feed functions correctly. 

While the technique works perfectly for X,Y moves, IJ interpolation causes things to go bonkers. If anyone has any mathematical reasons why that may be, I’d sure like to hear them along with any suggested solutions.   

Hope this little math exercise is of some help to others.

10
General Mach Discussion / Help!!!! Mach gone crazy
« on: December 06, 2007, 09:43:03 PM »
I'm running Mach2 (registered) so forgive me. Everything was fine the other day. I tried running some 4th axis stufff and the I & J commands were driving Mach2 crazy after I did a search & replace  substituting A for Y in the NC code.

Anyway I went to run a conventional job today (no A axis involvement) and the thing is feeding way too fast. My coded feedrate is .5 and 1 and the thing is running 6 even though the chosen feedrate display says 1. Mach defaults to FRO of 6 when initially booted up. THe readout indicates 6 and on Z retracts 15. I've checked every setting against the defaults and can't find anything. I've reduced the feed rate to %20 using the F10 key but it's still too fast and doesn't sound right.  :o I'd do a fresh install but it would be a royal pita to set all the ports, backlash etc. Any ideas? I've tried running the same jobs that I've run previously, and all exhibit the speed up issue.   

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