Messages

21

VB and the development of wizards / Re: Using VB script to wait for an external event and then execute G code

« on: September 07, 2008, 12:12:50 AM »

For example, can I use the following type of script:

Set colMonitoredEvents = objWMIService.ExecNotificationQuery _
    ("SELECT * FROM __InstanceCreationEvent WITHIN 2 WHERE " _
        & "Targetinstance ISA 'CIM_DirectoryContainsFile' and " _
            & "TargetInstance.GroupComponent= " _
                & "'Win32_Directory.Name=""c:\\\\automation""'")

Do
    Set objLatestEvent = colMonitoredEvents.NextEvent
   
REM  Then execute appropriate movement of stage and then loop.

22

VB and the development of wizards / Using VB script to wait for an external event and then execute G code

« on: September 06, 2008, 10:44:42 PM »

I am using a Sherline mill as an X-Y table with the goal of automating a sampling machine in my laboratory.  I have the mill set up and it seems to function fine under Mach 3.  The laboratory sampling machine (spectrometer) is able to take a data point at specific time intervals.  I would like to move the samples on the X-Y table using mach 3 so that a new sample is moved into position under the spectrometer after a data file is written.  The spectrometer is set up to sample for 1 minute, wait 20 seconds, sample for 1 minute, wait 20 seconds, etc.

I would like to write a VB script to be the interface between Mach 3 and the spectrometer file writing events.  I was thinking that I could run a VB script in Mach 3 that would watch the directory where the spectrometer stores its files.  Every time a new file appears I would like this event to result in the execution of some G-code that moves the x-y table to the next sample. 

Can anyone here tell me from the start if this is reasonable or if there is some reason why this could never work?

I am a novice with both VB script and mach 3 but since what I'm trying to do is really very simple I am optimistic about my chances of making it happen.

I'll put a tad more detail in here for those that are interested.  There are 96 samples on a 8 X 12 grid with exactly 9 mm between sample centers.  The movement would simply be to step through this grid in a systematic fashion.   Mach3 would move to the first spot and then wait until a file appears in the directory of interest.  These files will be numbered from 1 to 96 in case that helps (number at the end of a string in the file name - name_#.spc).  When a new file or the next numbered file appears then mach 3 will see it and then simply move the table to the next sample in the sequence.  Then it will wait for the next file to be written, etc. 

Any basic suggestions on how to accomplish this most efficiently would be greatly appreciated.  This is the only task that Mach 3 and the mill will do.

23

General Mach Discussion / Re: Fishing for comments on my scientific automation application with a Sherline

« on: June 01, 2008, 04:04:09 PM »

Where are you located.

Atlanta.

Jimpinder, thanks for the tip that Mach 3 can be manipulated with Visual Basic - that may be an easier way to do that scripting/program for my application.  however, I don't know if I would say 'wrong' side of the pond, just 'other' :-).

I think it's going to be a pretty simple thing to do once I get my phototransistor rigged up as an input and the mill set up and running with Mach 3.  I'm still working on that part.

24

General Mach Discussion / Fishing for comments on my scientific automation application with a Sherline CNC

« on: May 28, 2008, 04:23:05 PM »

Hello all,

I am using a Sherline 3 axis mill with 3 servos, a xylotex controller and Indexer LPT from Ability Systems to send instructions to the motors.  I am using the system in my laboratory as an automation platform.  The mill moves a 96-well plate under a laser (Raman) probe every two minutes while a machine records a spectrum for each of the 96 samples.  Right now I have a rather poorly syncing batch file running that uses dwell events to try to keep the movements of the mill in sync with the spectrometer.  This doesn't work very well. 

I would like to reconfigure the system to make the sync tighter.  It seems to me that I could use a G-code sequence to move the platform and a suggestion was made to make the 'laser on' LED into a trigger for the mill movement.  I can rig up a photodiode/phototransistor to generate a hi-lo signal that I can feed into the parallel port.  I was thinking that some kind of stop/wait signal could be issued and the resume command would come from the change from hi to lo when the spectrometer finishes the data point and the light goes off.  This triggers the movement to the next well.  The spectrophotometer runs in a mode where it takes a spectrum for 2 minutes, waits for 15 seconds then starts the next spectrum.     

I could have this programmed in a number of ways I suppose but I thought that if I did it using a program like Mach3 then I will also end up with a functioning 3 axis CNC machine.  This would be handy for me to make parts for the lab.  Very handy indeed.

So, what I am asking this forum is:  Do you think the above concept is possible?

If it's possible, I'm then going to wonder if I have the time or patience to get everything wired up, Mach3 configured, and the sequence written in G-code....  I don't think I do.

I know that the following probably sounds a bit on the insane side, but because of constraints on my tine and my minimal knowledge of all things CNC, what I would ideally like to do is find someone that I could pay to help me set up this system.  I can ship the computer, parallel card, motor power supply, controller board, the complete sherline mill, a sample well-plate, a paid license for Mach3, the phototransistor assembly, and any other necessary parts to put the system together.  The spectrometer can be simulated with a flashlight.  This person, for an appropriate fee, would assemble the parts, install and configure Mach3, and then write a file that accomplishes the automation process described above.  Lastly, once I get the system back, this person could provide tech support for an hourly fee for both the automation process and also to get me up and running with making simple parts out of aluminum on the mill. 

Boy, I am probably going to get flamed really bad for this post. Well, you gotta shoot to score....