On Tue, Jan 18, 2022 at 06:15 AM, Gerry Byrne wrote:

The four wires coming from the motor are (left to right with the terminal facing you) 1,2,3,4 and are connected to the axis terminal in the following order (from left) 4,2,3,1. For Axis one I am using temporary connectors so that I can change them around easily but the Axis 2 wires are soldered to a proper connector for the terminal. All have been circuit tested.

Are they off the shelf 4-pin to 6-pin 4-wire 3D printer cables?
Or are they custom made by you?
If they are the off the shelf type, the probability of errors are less (though not zero).
They are real time savers over custom made cables.

And do you have anything else between the drivers and motors? Such as RJ45 breakout
boards, and/or RJ45 cables? It would help to connect the motors directly to the Axis1
and Axis2 4-pin connector until we get to the bottom of this. The less components
in the path, the easier it is to troubleshoot ...

Another thing is the motors, are they geared? Those gearboxes usually have insane
amount of backlash, and maybe they are not reversing because you are using very
low speed, and not enough time to get over the backlash.

If you use a higher speed (say 1/2 Max), maybe you will see the motor eventually
go into the reverse direction?

On Tue, Jan 18, 2022 at 03:25 AM, <lrosellpardo@...> wrote:

After tuning backlash and leveling base seems now it's tracking fine.

These planetary gears from OMC have a terrible backlash but enough for visual.

Thanks Khalid

OnStep provides for up to 1 degree of backlash (3600 arc seconds).

Good to hear that this is all it is ...

This should not be an issue.  Your fan may not operate with as high as an RPM as designed, but you seem to be OK with that.  As long as you are not using the E0 Diag slot with a stepper driver, taking the 5V from there should be no different than taking it from EXP1 or EXP2.

Peter,

I haven't tested extensively, but I successfully unparked from the sequencer last weekend.

Lloyd

Check the voltage on the enable pin (pin 1 on the driver) during and after a drive (we're not slewing anywhere I suspect).  Make sure it is low (~0v) during the drive.  
Bob

Ok good idea to try swapping the stepper drivers around, I'll try that.

As for the jumpers, my board came with the jumpers pre-configured for spi mode enabled.

On Mon, Jan 17, 2022 at 08:08 PM, Otto wrote:

On the volt/Amp meter, how do you diagnose if you are imbalanced?  Are you looking at balance in both the RA/Dec axis?

Otto,

The ammeter is in line with the ground between the external connector and the PCB.  Doing one axis at a time, one is looking for the current draw when slewing to be the same CW and CCW. This particular ammeter measures up to 3A. 

Peter

Khalid,
I've ordered replacement LV8729s from Germany, should be here in a couple of weeks.
Both axes displayed the same behaviour, even when I changed from one set of drivers to another. By changing the wiring pattern I was able to reverse the direction of motion (i.e. from anti clockwise to clockwise) but they still did not reverse when commanded. I also tried giving commands via the serial monitor without success: they continued to move in the same direction. Otherwise they moved very smoothly and ran quite cool.

One set of the LV8729s were definitely installed on a Blue Pill PCB that I once fried. I told Howard the other set were new although, on reflection, they may have been aboard a FYSETC I accidentally shorted from beneath by putting it down on a stray piece of bare wire.

The four wires coming from the motor are (left to right with the terminal facing you) 1,2,3,4 and are connected to the axis terminal in the following order (from left) 4,2,3,1. For Axis one I am using temporary connectors so that I can change them around easily but the Axis 2 wires are soldered to a proper connector for the terminal. All have been circuit tested.
Gerry

--
Copernicus

Hi,

I've got OnStep running already on a Fysect S6 and I'm working on a case for it now. I have a small fan laying around and I thought I could use it for this build, but I know little about electronics in general so I'm wondering: is it OK to draw some power from one of the unused connectors in this board?
I read in the wiki that fans are not supported, but I'm guessing this means "you can't control them", and I just want it to be always on. It is a 12v 0.16A fan but I don't want it to run on full speed, so connecting it to a 12v line is not an option. I tested it with 5v on the port labeled as "E0-DIAG" and it works perfectly but, is this safe or I'll fry the board at some point? Also I've no idea whether or how this interacts with the motors (it's called E0 after all). Would the EXP1 or EXP2 ports be a better option?

 

Thanks!

Ok, too bad.

Regarding drivers, it shouldn't matter. If you didn't try it already, I would swap the bigtreetech to one of the working axis, try both focuser with fysetc and slew with bigtreetech, just to be sure that it works properly. I presume that you changed board jumpers for spi, right?

After tuning backlash and leveling base seems now it's tracking fine.

These planetary gears from OMC have a terrible backlash but enough for visual.

Thanks Khalid

Dave... Could you comment on whether you have dampers/flywheel weights on your steppers?
and If you do, from personal experience perhaps you can help us in improving Guy Brandenburgs
setup.

The MKS allows you to have both external power and USB connected at the same time BUT, you have to do it in order.  I always connect my external 24v power first, and then I connect USB.  Then the reverse when turning off…disconnect USB first, then remove external power.

On Mon, Jan 17, 2022 at 01:44 PM, Curly wrote:

Private joke I think ;)

I get the joke, I remember... :)

On Mon, Jan 17, 2022 at 07:01 PM, Khalid Baheyeldin wrote:

If you don't need the additional features of a Max, then the MiniPCB is a tried and tested board.

George Cushing sells them.

Thanks Khalid and to all who have responded.  I've got a message into George.  I'm thinking of the MiniPCB route.

On Mon, Jan 17, 2022 at 09:40 PM, Peter Boreland wrote:

Otto,

I just completed my build using the MaxESP3. I was able to squeeze in a 4 digital Volt/Amp meter after modifying it:), which I use to balance my axes.  In this build my drivers are external to the controller,.  I am thinking of changing out the power connectors for 2 pin aviation plugs to avoid any possibility of power disconnection to the motors.

Peter

Very nice Peter!  On the volt/Amp meter, how do you diagnose if you are imbalanced?  Are you looking at balance in both the RA/Dec axis?
Do you have a picture of the internals you can share on how you wired/connected everything?
Thanks!

These look interesting: https://motor.mtl.co.jp/dcms_media/other/%CE%BCDD_Motor_EN202006_B1.pdf

Not sure what spec one needs to build a Plane Wave style mount though?

Peter