Why would I not find it helpful? You are the CNC guy right? What I don't find helpful is people telling me they have read an article that I posted a link to and that it is "welly" written.

But this might be a better deal. Does it look like it will work?
https://www.ebay.com/itm/5X-Dual-H-...752336?hash=item33cbc0f410:g:bwIAAOSw7U5Y-XC3

Heatsink and everything too.

I don't know why you don't seem to like any of my input, it just comes across that way.
I'd stay away from the one you linked to. Like my suggestion in one of your other threads about a way to cut sheet metal without access to a shear. I make quite a few things from sheet and it has worked great for me.

The ones I linked to are really pretty good. Two inputs for direction and step rate, four wires out to motor, and two for power. They are pretty much what the older very expensive industrial controllers had. The whole frame of the controller is thick aluminum and makes up the heatsink.

 

So where is the video link for setting current limit? I could have sworn philba or someone posted a link,

The current limit is set based on the current rating of the stepper, which unfortunately you don't appear to have.
Therefore it is going to be something something that is based on empirical evidence?
Max.

 

The current limit is set based on the current rating of the stepper, which unfortunately you don't appear to have.
Therefore it is going to be something something that is based on empirical evidence?
Max.

Yes but there was still a video, or at least I thought.

 

Are there different configurations of these? I seem to have this:

https://www.ebay.com/itm/A4988-Step...554382?hash=item33a3082e0e:g:-nUAAOSwi8xaA0Zz

But it does not match up to any of the datasheets I have found.

 

Ah I see the problem. The printing is upside down on the reverse side. A bit disorienting at first.

 

I know I posted that link. Not sure what happened. Don't think I violated any TOS. Here it is again - https://www.pololu.com/blog/484/vid...limit-on-pololu-stepper-motor-driver-carriers

 

With 3.7 ohms, 800 mA is the current (well, 810, actually). I'd start at 500 mA to be safe. Do you have some way to measure the temperature?

 

With 3.7 ohms, 800 mA is the current (well, 810, actually). I'd start at 500 mA to be safe. Do you have some way to measure the temperature?

I have a couple of those electronic thermometers.

 

I know I posted that link. Not sure what happened. Don't think I violated any TOS. Here it is again - https://www.pololu.com/blog/484/vid...limit-on-pololu-stepper-motor-driver-carriers

Yeah found it on their site too.

And at least I know I am not crazy. OK I am but at least not in this instance.

 

Apparently you need to know the value of the current sense resistors to be able to calculate the current. I bought mine before January 2017 but mine look like neither of these



Here is mine

 

S1 and S2 are your sense resistors. I can't quite make out their values in your picture.

By the way, if you have a non-conductive screw driver, you should use it when adjusting the trimmer. There have been stories of people using metal screw drivers and shorting something out.

 

S1 and S2 are your sense resistors. I can't quite make out their values in your picture.

Looks like it says R100. I never really looked at SMD is that 100 ohms?

By the way, if you have a non-conductive screw driver, you should use it when adjusting the trimmer. There have been stories of people using metal screw drivers and shorting something out.

Funny the video suggests a metal screwdriver to make life easier on adjustment.

 

Looks like it says R100. I never really looked at SMD is that 100 ohms?

Or is that 10 ohms? Did some reading looks like 0 is the 10^0 multiplier.

 

Looks like it says R100. I never really looked at SMD is that 100 ohms?



Funny the video suggests a metal screwdriver to make life easier on adjustment.

If you say R100, I think that is 10 ohms.

 

Yes normally, that would 10 ohms, 3rd digit is multiplier. But that doesn't make sense. I'm betting 100 mOhms.

 

Anything is possible but the chip wouldn't work right because current sensing is at the heart of the A4988.

 

Now that I think about it, 100R would be 10 ohms, this is R100. This should be 0.1 ohm

 

It is .1 Ohms

 

I think this wiki explains things a little better than even the video

http://reprap.org/wiki/Pololu_stepper_driver_board#Tuning_motor_current