will1384's Shapeoko 2

cvoinescu
Posts: 4442
Joined: Thu Jul 19, 2012 6:50 pm
Location: Camberley, UK
Contact:

Re: will1384's Shapeoko 2

Post by cvoinescu » Tue Aug 26, 2014 10:49 am

Using your multimeter (on volts DC, and if it's not auto-ranging, select the 2 V scale), measure between one of the solder joints circled in red in the image and ground (the screw marked GND on the two-terminal screw connector). Read the voltage, then follow the calculations to find out what the current is. Adjust by turning the small screw-like knob on top of the trimpot. Clockwise is more, counter-clockwise is less. Do not exceed the current rating of your motors, and take care not to touch anything else with the probes while measuring.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

sectorix
Posts: 46
Joined: Wed Jul 23, 2014 9:44 pm

Re: will1384's Shapeoko 2

Post by sectorix » Tue Aug 26, 2014 5:29 pm

cvoinescu wrote:Using your multimeter (on volts DC, and if it's not auto-ranging, select the 2 V scale), measure between one of the solder joints circled in red in the image and ground (the screw marked GND on the two-terminal screw connector). Read the voltage, then follow the calculations to find out what the current is. Adjust by turning the small screw-like knob on top of the trimpot. Clockwise is more, counter-clockwise is less. Do not exceed the current rating of your motors, and take care not to touch anything else with the probes while measuring.
From which 2 points should I measure ? on the bolted bracket on grblshield? a picture would be wonderful

secretspy711
Posts: 175
Joined: Thu Jun 12, 2014 7:55 pm
Location: Colorado

Re: will1384's Shapeoko 2

Post by secretspy711 » Tue Aug 26, 2014 8:49 pm

cvoinescu already said it:
measure between one of the solder joints circled in red in the image and ground (the screw marked GND on the two-terminal screw connector).
Image
Shapeoko 2 #5510: 1200 x 500 mm, Makita RT0701

cvoinescu
Posts: 4442
Joined: Thu Jul 19, 2012 6:50 pm
Location: Camberley, UK
Contact:

Re: will1384's Shapeoko 2

Post by cvoinescu » Tue Aug 26, 2014 9:48 pm

Yeah, what he said that I said. You had the picture in your own post.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

sectorix
Posts: 46
Joined: Wed Jul 23, 2014 9:44 pm

Re: will1384's Shapeoko 2

Post by sectorix » Wed Aug 27, 2014 1:23 am

Thanks. will try!
obviously new at this

tornwing
Posts: 2
Joined: Thu Apr 30, 2015 9:52 am

Re: will1384's Shapeoko 2

Post by tornwing » Thu Apr 30, 2015 4:20 pm

will1384 wrote:Part (4) wiring.

~

so I think I would need 1.3v on VREF

1.3 / 0.8 = 1.625


Is this correct?

I am going to finish wiring up the stepper motors and testing the CNC control box tonight, lets hope I don't let the smoke out of it :shock: LOL
Hi there

I am a newbie for shapeoko 2 assembly (also electrics).

I just bought gshield board for driving shapeoko 2 before a few months.

As you know, Y axis in SO CNC is driven by two stepper motors .

I looked up this post, if I wanna make stepper motor work efficiently, I have to adjust Verf on Gshield for rated current of stepper motor.

I got the caculation for I=Verf/0.8.

The rated current of my Nama 17s is 1.3A, so I adjusted Verf become 1.035 V (Iref=1.29).

However, in parallel, the currency will become larger. I remember gshield just serve 2.5 A. Once the Nama 17s are paralleled, the total currency (Iref in Y) will become 2.58A to damage Ti8818. Do I get wrong?

Thanks for your help.

cvoinescu
Posts: 4442
Joined: Thu Jul 19, 2012 6:50 pm
Location: Camberley, UK
Contact:

Re: will1384's Shapeoko 2

Post by cvoinescu » Thu Apr 30, 2015 5:07 pm

Well, sort of. You're right that the rated current of the two motors in parallel will be 2.6 A, but that just means the DRV8818 won't be able to supply the full current. It won't break.

It's unlikely that you'll get close to 2.5 A without some serious cooling. I would simply adjust the reference to the highest current that doesn't cause the driver to go into thermal shutdown in your setup, then dial it back 20% or so.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

tornwing
Posts: 2
Joined: Thu Apr 30, 2015 9:52 am

Re: will1384's Shapeoko 2

Post by tornwing » Mon May 04, 2015 10:09 am

cvoinescu wrote:Well, sort of. You're right that the rated current of the two motors in parallel will be 2.6 A, but that just means the DRV8818 won't be able to supply the full current. It won't break.

It's unlikely that you'll get close to 2.5 A without some serious cooling. I would simply adjust the reference to the highest current that doesn't cause the driver to go into thermal shutdown in your setup, then dial it back 20% or so.
Hi cvoinescu

Thanks for your advice. :D

Because my stepper motor in the X-axis is Nema 23 driving in 2.5A, absoultely, I got the Verf close to 2.0V.

I know Ti8818 cooling is a big issue, so an 8cm fan and fins were prepared.

Thus, I also adjusted the Verf in Y axis almost 2.0.

I am not sure the cooling system is enough or not.

Image

Thank you so much.

Post Reply