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Slowing down a plotter

Hi all,

I've got a Roland DXY series plotter that I use to directly draw PCB tracks on copper. I'm currently getting acceptable results but it would work much better if I could further reduce the plotting speed (yes, I'm already using the slowest speed).

I don't have experience with stepper motors but I assume (wrong?) that if I run the microcontroller on the plotter mainboard at 1/2 the current clock speed, the plotting speed with also becamo just 1/2 of the original. I expect that (at least) as a side effect the serial port communications will also require 1/2 the bps speed.

I'm thinking in changing the crystal (I haven't even checked it's frequency yet) and give it a try.

Could it work at all? Am I completely wrong?

Thanks a lot, Roberto

Reply to
rbarrioss
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I think I still have one of these hanging around here somewhere. I did the same thing many years ago, that is, draw directly to copper.

From what I recall, it wasn't a great job either. Glad some decent CAD packages came along that allowed us to submit artwork directly to manufacturers.

But the nature of rs-232 comms means halving your crystal frequency, should allow you to run your comms at half speed without error.

Don't know about any other time critical functions of the Roland. I would suck it and see. What have you got to loose?

Don...

Reply to
Don McKenzie

seems like it would work....

maybe instead: cut the traces that power the transistors that go to the stepper... put a circuit between the ?CPU? and the transistors that will "divide by two". should be able to do that easily with a PIC...

how many coils does the stepper have?

on PIC:

INPUT1 (coil 1, from plotter CPU) INPUT2 INPUT3 INPUT4

OUTPUT1 through 4 (going to driver transistors)

state1 through 4 (variables holding previous state of INPUTS)

when input1~4 state1~4, the CPU has stepped the motor.

you would need a table of some sort to OUTPUT to the driver transistors.

Reply to
aiiadict

cards.http://www.dontronics-shop.com/product.php?productid=16659- Hide quoted text -

Yes, I'll give it a try.

Thank you Roberto

Reply to
rbarrioss

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