Bridgeport Boss original drives

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03 Jan 2017 18:19 #85154 by AThayer
I am trying to convert a Boss 5 to use linuxcnc. The drives use quadrature drive. I have a Parallel breakout board. Anyone doing this?What does your hal look like? I can get the stepper motor to make a little noise when I first try to jog the axis. I was wondering if the on time of the pulse is wrong for the drives. Any ideas and or help. Thanks

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03 Jan 2017 20:03 #85162 by andypugh
Have you set the step generator to quadrature mode?
There is no such thing as a fixed on-time for quadrature.

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03 Jan 2017 20:57 #85165 by AThayer
Yes does anyone have a hal file I can see.

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03 Jan 2017 22:38 #85175 by AThayer
I'm wondering what a Hal file would look like. Can anyone explain block diagram in following? linuxcnc.org/docs/2.5/html/hal/rtcomps.h...stepgen_step_types_a

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03 Jan 2017 22:56 #85176 by andypugh
The HAL would look almost identical to any other stepper HAL file, the only difference will be:

loadrt stepgen step_type=2,2,2 ctrl_type=p,p,p

(from linuxcnc.org/docs/2.7/html/man/man9/stepgen.9.html )
The following user(s) said Thank You: AThayer

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04 Jan 2017 16:23 #85226 by AThayer
I see based on that document that steplen does work with quadrature output. So how can I use halscope to see the waveform of the output?

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04 Jan 2017 16:44 #85232 by andypugh

I see based on that document that steplen does work with quadrature output


It can't. If the pulses are a fixed length then it can't possibly be quadrature.

The HAL parameter will still exist but shouldn't have any effect.

You should be able to see the actual waveform on the parallel port pins in Halscope, and also on the stepgen output pins. (and if they don't show exactly the same thing, that might be the problem).

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04 Jan 2017 17:02 #85236 by AThayer
OK my understanding is I need two square waves that are 90 degrees out of phase to one another. I was looking at controlling the length that the pulse is on and off. Also I'm trying to find code to do this with arduino for testing purposes.

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04 Jan 2017 17:08 #85238 by andypugh
Not exactly. Quadrature pulses look like
00
01
11
10
00
And so on. Every time you want a step you advance through the sequence.
It's a good way to control a drive, as you only need a single transition on one channel to signal a step, whereas step/dir needs two transitions.

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04 Jan 2017 17:19 #85241 by AThayer
So what controls on long each phase is on or off?

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