Step it up a notch 80v

[joecnc2006]

Been doing every day for a week now. Whent he rain stopps I'll crawl under the truck and replace them.




I got them still. But their in a box and the turn table hasn't been hooked up for a few years.

Now getting down to the actual issue of selection and recomendations using Gecko as a model.

1. How important is short circuit protection? I assume it wouild be quite important so I hesitate to ask something this dumb.

G201/202 7A, 80VDC 10-microstep drive

G210/212 Full-step, Half-step, 5 and 10-microstep

2. Is the ability to do the extra step sizes in the 210 going to actually add something to my system, or, based on your previous posts, it sounds like I will probably end up setting the thing to 10 microstep and just leaving it there since it defaults to full step (or a square wave approximating full steps) above a certain feed rate?

(application is a 34X60 inch router table used exclusively for wood and mainly used for cutting and shaping the top and back plates for violin family instruments in size ranges from the violin, 14" body length up to the double bass at a 49" body length.)

Steven

Yes I have the same Question, I am thinking just bite the bullet and get the gecko, but which one? a good DIY machine driver, for maybe 600oz/in size motors.

I have the Keling 425oz/in. nema 23 motors to start. it will be a DIY 4'x4' machine to start then expand it to 8' long , modular 80/20 system. Based on Shopbot type construction.

Joe

[ger21]

If a wire breaks, or comes loose, or you wire something wrong, the G201 will die instantly, the G202 won't. To me, that would make it worth the extra $20

As for the G212, you really would only need it if your PC can't output steps fast enough to keep up.

With Steven's example of 10 tpi screw, and 1/10 microstepping, you need 20,000 steps/inch (200*10*10). With Mach3's limit of 25,000 steps per second, that's 1.25 inches per second, or 75 ipm. If you want to go faster, and your PC is fast enough, you can increase Mach's kernel speed to 35 or 45 Khz, which would give you 105 ipm and 135 ipm, respectively. If you want to go any faster, you'd want to use the G212.

I'd personally go with a higher lead screw, as that 10 tpi screw will probably start whipping around pretty good at those higher rpm's.

[Mariss Freimanis]

The only reason to use half-step or full-step is if your CNC software cannot provide a high enough step pulse frequency for microstepping.

Example 1: Your CNC software puts out 20,000 steps per second maximum.

10 microstep drive = 600 RPM
half-step drive = 3,000 RPM
full-step drive = 6,000 RPM

You trade in resolution for speed.

Example 2: Mach3 puts out 45,000 max. That works out to 1,350 RPM at 10 microsteps. That speed is sufficient for most applications.

The G201/G210 doesn't have short-circuit protection, the G202/G212 does. That's the significant difference between them.

Mariss

[sdantonio]

Gerry,

I was going to look into a higher lead screw if whipping became a problem. But I know Joe is running 70imp on the same screw. So I figure it's a good place to start.

Thank you for the advice gentlemen. Then it looks like the G202 it is.

The computer is a 1gig machine right now, but can always be upgraded easily.

Steven

[lastguy]

Misconception 1. Microstepping decreases torque:

An 800 in-oz motor direct-driving a 5TPI screw would have to encounter a 245 lb load to disturb the motor 1/10 of a full step.

Lbs = sin 9 deg * pi * TPI * in-oz / 8
Lbs = 0.156 * 3.14 * 5 * 800 / 8
Lbs = 245

Mariss

why sin 9? 1/10 full step is 0.18deg. why divided by 8? thanks

[Mariss Freimanis]

1.8 degrees mechanical equals 90 electrical degrees.

Mariss