Centroid Community CNC Support Forum

Marty,
Thanks for your support, I do appreciate it. I have everything wired up including the stepper drivers and stepper motors and no smoke yet. Looking at section 4 of the RTA manual - Input and output signals - I wired the Acorn outputs for the driver mother board (As they call it) as follows:

Acorn step to RTA L6 Step input (I noticed in the RTA manual that RTA limits the step frequency to 50KHZ and I don't know what acorn puts out, possibly exceeding what the board can handle. Noticed a reference in the Wizard axis set up of a selectable frequency of either up to 400.000 or up to 200.000 - I have it set to the 200.000 )

Acorn direction to RTA L5

Acorn enable to RTA L7. (As per your earlier recommendation I inverted the enable in the Wizard advanced axis set up and it improved somewhat by not immediately going into drive fault. it now goes into drive fault after trying to move the stepper motor a couple of times manually. It still does not move, figure the step frequency is my problem.)

Acorn ground to RTA L8 GND

What do you think? Its an old driver board design based on legacy technology. Hate to toss them and invest $ 600.- for new driver boards. Them old driver boards and stepper motors worked fine up to the time when I tore down the control panel and wired in the Acorn.

Peter

Oldtimer wrote: ↑Thu Jan 25, 2018 8:24 pm Marty,
Thanks for your support, I do appreciate it. I have everything wired up including the stepper drivers and stepper motors and no smoke yet. Looking at section 4 of the RTA manual - Input and output signals - I wired the Acorn outputs for the driver mother board (As they call it) as follows:

Acorn step to RTA L6 Step input (I noticed in the RTA manual that RTA limits the step frequency to 50KHZ and I don't know what acorn puts out, possibly exceeding what the board can handle. Noticed a reference in the Wizard axis set up of a selectable frequency of either up to 400.000 or up to 200.000 - I have it set to the 200.000 )

Acorn direction to RTA L5

Acorn enable to RTA L7. (As per your earlier recommendation I inverted the enable in the Wizard advanced axis set up and it improved somewhat by not immediately going into drive fault. it now goes into drive fault after trying to move the stepper motor a couple of times manually. It still does not move, figure the step frequency is my problem.)

Acorn ground to RTA L8 GND

What do you think? Its an old driver board design based on legacy technology. Hate to toss them and invest $ 600.- for new driver boards. Them old driver boards and stepper motors worked fine up to the time when I tore down the control panel and wired in the Acorn.

Peter

Peter, You have LED's that flash a pattern during a fault do you not? (Manual page 12)
What are they telling you.

Acorn outputs 200KHZ if your drive can only take 50KHZ, this may well be your problem. If you were running under Mach parallel port, I bet it worked.

Hello Marty,
Yes, the LED's are indicating as follows:

Upon applying power to the control system, the HV (High voltage) green LED lights up and I can hear the power inrush into the stepper motor and feel the power inrush bump at the stepper motor. So all is cool until I try to start manually to turn the stepper motor via the PC display. Having the enable setting in the Wizard inversed as you suggested improved things a little because now the fault LED does not immediately light up but maybe after two tries to turn the stepper motor via the PC. So the LED pattern is then green HV LED on and red fault LED on. According to the manual that combination is supposedly "Short circuit at motor output or drive broken"

As I mentioned earlier, all the stepper boards worked fine in the old control set up. I do know that in the old control set up the control board stepper outputs were configured / modified to fit my RTA stepper boards to work. Not knowing anything about the inner workings of the Acorn but having looked at the various schematics available to wire the Acorn, I picked the generic wiring schematic and set the Wizard up under "other" for my stepper boards. In the Wizard are a number of other stepper board choices but I don't know whether and which one may be closer to what my boards need to operate. I.e. is there a profile / setting in the other stepper choices that for instance provides a different output set up (Lower step frequency setting of say 50KHZ for example) and could be used in my case by maybe picking a different stepper board choice? I was wondering whether the listed stepper board choices, when selected, provide a different operating profile and variations in the associated stepper board functions and in the outputs to the boards. I hope I made myself clear in what I am trying to say here.

I tend to agree with you that the step frequency limitation of my existing boards may be the root cause of my problem. Now if the step frequency output from the Acorn can not be reduced by selecting a different stepper drive set up or internally in the Acorn, I guess I have to bite the bullet and go with modern tech stepper boards. Would you have a recommendation as to what stepper boards to evaluate? My stepper motor power supply is a torroidal transformer with a 55 VDC / 4.5 Amp / and 250 VA output. My stepper motors are VEXTA 2 phase / 1.8 degree step / DC 4.5 Amp / 0.66 Ohm.

As an aside, once I have myself completely familiarized with the how to of posting on this forum I will provide more details and pictures about the mill I am trying to run with the Acorn.

Peter

I am partial to GECKODRIVE: http://www.geckodrive.com/geckodrive-st ... rives.html
Pick one that fits your voltage requirements.

Automation Technologies has a number of stepper drivers, I can't say that I have used them all:
https://www.automationtechnologiesinc.c ... r-drivers/
https://www.automationtechnologiesinc.c ... or-driver/

Marty

Hello Marty,
Thanks. I will take a look. Seems I am out of luck with my old driver boards. Not heavy enough for boat anchors.

Peter

Hello Marty,
I looked at the Gecko drives and Automation Direct and I am interested in two Gecko drives. The 201X and the G214. Both differ not much as far as cost is concerned and I tend towards the G214. I know that the Gecko 201 is featured in the list of the Acorn schematics but not the G214. I assume that a Acorn schematic for the G214 would closely resemble the 201 schematic and wonder if you could confirm that and possibly point out differences between schematics. If you had a choice, which gecko controller would you go for? Thanks.

Peter

The 201 is a tried and true design. But the 214 is newer technology. I would lean toward the 214.
Looks like a nice drive. Yes, you could use the 201 schematic as a guide.

Tbe folks at Geckodrive are good knowledgeable people. Can't go wrong with them

Marty