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Author Topic: Mach as a linear indexer help  (Read 3615 times)

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Re: Mach as a linear indexer help
« Reply #10 on: February 21, 2014, 06:11:10 PM »
Gary,

Please send links to the Direct components you reference.  There are numerous hits on DL06.  I like the concept . .  we built a PLC controlled edging cross-cut saw.  I outlined the ladder, but we used outside resources to actually program it.  We also have other PLC stuff and have just as much trouble with them as anything else.  I actually have a PC that has been running since 1998 without failure. It runs DOS and a CNC Router. If the grid is up, it's up.  However, I am on my third high buck touch screen panel mount PC for the current router project.

The fence we are working on weighs about 500 pounds and has about 12 inches of travel. Although it would be nice to count pieces, it is not a feasible task.  What did you have in mind for the HMI?  The fence has a variable zero and a fixed Zero.  The operator would need to set the variable zero and then enter the desired offset values from that zero . . . usually not more than 4 total.  The fixed zero has 5 negative values.            

      

Look at: http://www.automationdirect.com/adc/Shopping/Catalog/Programmable_Controllers/DirectLogic_Series_PLCs_(Micro_to_Small,_Brick_-a-_Modular)/DirectLogic_06_(Expandable_Micro_Brick_PLC)/PLC_Units/D0-06DD1  This will do pulse and direction up to 7 Khz without any other modules.

Add: http://www.automationdirect.com/adc/Shopping/Catalog/Programmable_Controllers/DirectLogic_Series_PLCs_(Micro_to_Small,_Brick_-a-_Modular)/DirectLogic_06_(Expandable_Micro_Brick_PLC)/Motion_-a-_Specialty_Modules/H0-CTRIO2  This will go up  to 250Khz or read a quad encoder.

Add: http://www.automationdirect.com/adc/Shopping/Catalog/Operator_Interfaces/C-more_Micro-Graphic_Panels/3_inch_Panels_-a-_Accessories/EA1-S3MLW
This give you some buttons and a pop up keypad plus data display.

You might be able to use a DC gearmotor and an encoder along with a drive like this: http://kbcontrols1.reachlocal.net/KBMG-212D-8831-SCR-Chassis-KBMG-212D-8831.htm  This will give you almost servo like performance of a big motor for low cost. You approach rapidly then slow way down for final position. If you always approach from the same direction you can remove backlash too.

Your fixed zero would typically be designated by a home limit switch. When you start the system it would move slowly to the home switch, then typically reverse until the switch reopens, that being your exact zero. Then all subsequent moves get calculated from there.

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Re: Mach as a linear indexer help
« Reply #11 on: February 26, 2014, 09:43:08 PM »
Thanks,  I just noticed the post.  I will have a look.  I was turning a blind eye to speed because is not an issue today, but when the depression is over we would regret having overlooked it.