Centroid Community CNC Support Forum

fozzyber,

YES, the direction output is either Positive or near zero. Think of this in terms of 1's and 0's. When the Acorn outputs the Direction signal as a "1" or high the motor will run one direction, and when the Acorn outputs a "0" or low signal it will run the other direction. Are you taking those measurements off of the Acorn screw terminals? Do you have pull up resistors and what voltage are they pull up resistors tied to?

If you take those same exact measurements with your scope from the DB25 port on Acorn they will max out just under 5V and very close to zero volts when you switch directions.

Russ

opps I mis typed that video is showing the STEPS or pul NOT Dir

No issue it looks correct to me. The Direction will stay high or low depending on which way you are driving the motors.

Russ

OK it been a long day but in the end I have hooked up the Diff line driver on one axis and it worked! I can move the axis back and forth and not lose steps. ( I am pulling step / dir signal from the DB25 on the acorn as cncman172 suggested with the diff line driver.

I started off the day when my friend came over with his scope. the first thing we found is a lot of noise down stream of the noise filters that DMM says is necessary for the motor power. So we by passed those filters with no change. next we read the signal from the acorn screw terminals.
for the pul ( steps ) that was strange, the video shows this test.
Acorn pulse signal
https://www.youtube.com/watch?v=jNdwG2EHUZE
https://youtu.be/jNdwG2EHUZE
what is strange here is i would expect to see a square wave pattern of 24v regardless of motor direction. ( FOR THE STEPS)
this is not what i'm seeing. What I was seeing is a 24v square wave when the motor was rotating CW, but a 5v square wave pattern when the motor was turning CCW. I was also seeing the direction pin in acorn going high and low as the motor changed direction , which is what i would expect.
we then hooked the scope to the DB25 on the acorn, It performed as expected. Steps were square wave regardless of direction. and dir was either high or low.
SO.. my question is what is going on here, what is the difference between the output signal between the acorn screw terminals and the signal from the acorn DB25 ?

And why would a noise filter introduce noise in to the line??? and yes it is hooked up correctly load side to driver and input side to curcut breaker.

Thanks guys I feel like I'm making progress.

jerry

Jerry,
Glad the differential driver is working for you, as I expected. The reason you are getting strange signals on the Screw terminals is they are open collector and if you had pulled those signals up with a 1K resistor to say 5V you would have see the signals you expect. Without being pulled up they will look very strange.

on your filters it is possible they are not grounded properly. There is normally a ground terminal on those filters and that must be tied to ground of the filter with its internal circuity will do nothing.

You are clearly making progress, congratulations. You will be making chips very shortly.

Russ

all looks good, one little issue of a motor losing a few at first start but then holds true. (50 encoder steps)
and this is my wiring. attachment below shows db25 connection

fozzyber,
Your last picture did not post.

Russ

fozzyber wrote: ↑Thu Jan 31, 2019 12:02 pm all looks good

Is the 5 volts needed on each end of the Differential Line Driver or just the input side ? ( referencing your rev6 schematic ). Perhaps it’s just in the drawing not an actual wire going to the RJ45 end ?

Jake

The diagram i got showed +5v on booth sides. Not sure why.
But that's is how i drew it and how i wired it. And it worked...

happy with the y axis so far...
https://youtu.be/JB16_LMfyf4