Date   

Re: TMC2130 listings on ebay

Howard Dutton
 

On Tue, Feb 11, 2020 at 02:02 PM, Howard Dutton wrote:
Very vague question with no specific brand mentioned but...

No that doesn't look ok.

From what I understand the Bigtree version 3 comes in two models a DIY version and an SPI version.
The SPI version seems to have two extra pins in the side holes as shown in this eBay listing.

I'm not sure some sellers even know what they're listing so good luck!
Again... that is NOT the correct driver.


Re: TMC2130 listings on ebay

thomas.westerhoff24@...
 

Hello Prasad .
Yes thats ok. These extended pins on the upper side are for the use in 3D Printers with older boards like the MKS GEN L v1.0. There are no SPI wires routed on the PCB itself and if yout want to use SPI you have to install additional wires. It's easier to install these wires on top of the driver module

See https://www.youtube.com/watch?v=OUadiW5QLBE


--
Thomas Westerhoff
Kirchheim Observatory /Germany
http://sternwarte-kirchheim.de/
https://www.facebook.com/VolkssternwarteKirchheim/


Re: TMC2130 listings on ebay

Howard Dutton
 

On Fri, Feb 14, 2020 at 03:57 AM, Howard Dutton wrote:
Its best to switch into SpreadCycle before slews
Although in some cases where the motor RPM is low enough (low reduction) you can stay in stealthChop for smoother quieter slews.


Re: TMC2130 listings on ebay

Howard Dutton
 
Edited

Ok now I understand.  StealthChop and SpreadCycle are "decay modes" (along with fast decay, slow decay, and mixed decay) and control how the driver manages delivering current to the motor coils. 

They have nothing to do with the micro-step mode.  StealthChop is essentially silent no noise but doesn't work well at high RPMs.  SpreadCycle makes some noise but allows the motor to run faster.  Its best to switch into SpreadCycle before slews since StealthChop to SpreadCycle can be like a bump in the road and has to happen at low speed.


Re: TMC2130 listings on ebay

Ant No
 

I think it's the word mode that's ambiguous to me. Mode as in stealth, chop etc or mode as in microstep rate?

Sorry to be dense.

Ant👣


On 14 Feb 2020 11:38, wrote:

I may not be fully understanding your previous answer.

Ant 👣


On 14 Feb 2020 11:37, "Ant No" <cmpaqp1100@...> wrote:

What I'm asking is if it is possible to use a TMC2130 or other driver with SPI to change microstep rate on the fly?

Not specifically in On-Step but in the way the SPI works on the drivers.

A person in a different forum with a different application would like to be able to. I had an idea it was possible but I'm not sure.

Ant👣


On 14 Feb 2020 11:30, "Howard Dutton" <hjd1964@...> wrote:
On Thu, Feb 13, 2020 at 05:19 PM, Ant No wrote:
Is that the way On-Step implements control or a limitation of the driver itself?
I don't understand the question.  There was a limitation as described but that limitation is now removed.


Re: TMC2130 listings on ebay

Ant No
 

I may not be fully understanding your previous answer.

Ant 👣


On 14 Feb 2020 11:37, "Ant No" <cmpaqp1100@...> wrote:

What I'm asking is if it is possible to use a TMC2130 or other driver with SPI to change microstep rate on the fly?

Not specifically in On-Step but in the way the SPI works on the drivers.

A person in a different forum with a different application would like to be able to. I had an idea it was possible but I'm not sure.

Ant👣


On 14 Feb 2020 11:30, "Howard Dutton" <hjd1964@...> wrote:
On Thu, Feb 13, 2020 at 05:19 PM, Ant No wrote:
Is that the way On-Step implements control or a limitation of the driver itself?
I don't understand the question.  There was a limitation as described but that limitation is now removed.


Re: TMC2130 listings on ebay

Ant No
 

What I'm asking is if it is possible to use a TMC2130 or other driver with SPI to change microstep rate on the fly?

Not specifically in On-Step but in the way the SPI works on the drivers.

A person in a different forum with a different application would like to be able to. I had an idea it was possible but I'm not sure.

Ant👣


On 14 Feb 2020 11:30, "Howard Dutton" <hjd1964@...> wrote:
On Thu, Feb 13, 2020 at 05:19 PM, Ant No wrote:
Is that the way On-Step implements control or a limitation of the driver itself?
I don't understand the question.  There was a limitation as described but that limitation is now removed.


Re: TMC2130 listings on ebay

Howard Dutton
 
Edited

On Fri, Feb 14, 2020 at 03:21 AM, Ant No wrote:
What I'm wondering is if the spi can allow microstep switching on the fly? There's someone in another forum relating to automating metal working machines that's interested in that.
This is still new code but, at this point, yes it seems to work properly.  I write to only the TMC CHOPCONF register and bit-bang it (no hardware SPI help.)  The reason being that we usually want universal StepStick driver support with our controller designs and you can't do that and have a single SPI bus to both Axis1/2.


Re: TMC2130 listings on ebay

Howard Dutton
 

On Thu, Feb 13, 2020 at 05:19 PM, Ant No wrote:
Is that the way On-Step implements control or a limitation of the driver itself?
I don't understand the question.  There was a limitation as described but that limitation is now removed.


Re: TMC2130 listings on ebay

Ant No
 

What I'm wondering is if the spi can allow microstep switching on the fly? There's someone in another forum relating to automating metal working machines that's interested in that.

I thought you'd know the answer.

Ant👣


On 14 Feb 2020 01:19, "Ant No via Groups.Io" <cmpaqp1100=gmail.com@groups.io> wrote:

Thanks Howard.

Is that the way On-Step implements control or a limitation of the driver itself?

Ant👣


On 12 Feb 2020 19:19, "Howard Dutton" <hjd1964@...> wrote:
For OnStep version 4:

Only the micro-step mode is switched on the fly.  The advantage being that you don't need to switch "just one or two levels".  For example, switch from 128x (tracking) to 4x for (slews.)
Now as before everything else (decay mode, current level, etc.) is switched before/after the slew.

This matters most for the Mega2560.


Re: TMC2130

Khalid Baheyeldin
 

On Thu, Feb 13, 2020 at 07:56 PM, Joe wrote:
I’m using a Canon 6DM2, it’s a full frame as opposed to a crop sensor. I believe the pixels on the 6D are a bit bigger than the T4i, but there are more if them, probably pretty close.
If I use Canon 6D on this calculator, with my focal length (1310 mm) it gives me 1.03"/pixel.
Not sure of the Mark II is different.

I’ll try to hit that 28,800 mark and see how it goes.
The difference between the recommended steps per degree in the spreadsheet (12,800) and mine (28,800) is close to double.
So maybe with your pixel scale being about double it will even out.
And if you are using a scope at 800mm or 1000mm, then it is even more likely that an LV8729 would do the job more than adequately.

I’ve got some concerns about the inefficiency of my mount. Are you using the PEC with your photography? Do you think that should be a priority to get some decent results?
I used PEC when I was not autoguiding. It was all an experiment to postpone autoguiding.
It helped, and so did the Full Compensation Tracking.
But when I switched to autoguiding, I found out that PEC makes no difference.
If the periodic error in your mount is gradual, then autoguiding may be sufficient to take care of it.
If it is too high and happens over a short period of time, then maybe in this case PEC will help.

So, my recommendation is not to bother with it, if you are going to try autoguiding anyway.
If you inspect the graph and see that there is a period, then at that point consider trying PEC.
You can do it without a sensor initially (just record it every session, or park the scope), and if it is helpful, then you can consider adding a sensor.


Re: TMC2130 listings on ebay

Ant No
 

Thanks Howard.

Is that the way On-Step implements control or a limitation of the driver itself?

Ant👣


On 12 Feb 2020 19:19, "Howard Dutton" <hjd1964@...> wrote:
For OnStep version 4:

Only the micro-step mode is switched on the fly.  The advantage being that you don't need to switch "just one or two levels".  For example, switch from 128x (tracking) to 4x for (slews.)
Now as before everything else (decay mode, current level, etc.) is switched before/after the slew.

This matters most for the Mega2560.


Re: TMC2130

Joe
 

Thanks Khalid. I’m using a Canon 6DM2, it’s a full frame as opposed to a crop sensor. I believe the pixels on the 6D are a bit bigger than the T4i, but there are more if them, probably pretty close. I’ll try to hit that 28,800 mark and see how it goes. I’ve got some concerns about the inefficiency of my mount. Are you using the PEC with your photography? Do you think that should be a priority to get some decent results?



On Thursday, February 13, 2020, 7:09 PM, Khalid Baheyeldin <kbahey@...> wrote:

On Thu, Feb 13, 2020 at 06:48 PM, Joe wrote:
I purchased a different set of GT2 gears for a better drive ratio on my Vixen GP. I had purchased a couple of the TMC2130s before doing research that unfortunately for me were the wrong version. I was unable to solder those really small jumpers on the bottom.
Soldering of these tiny components is very hard. Requires a steady hand, good eyesight, magnifier and experience.
Average people would like to avoid doing it, unless there is no other choice.

With the 3.16 OnStep release, if I’m reading correctly the correct driver would improve performance with using SPI? My question being is it enough of an improvement over the LV8729s to warrant buying them? 
SPI itself does not give an advantage.
What gives an advantage is all the Trinamic TMCxxxx drivers have 1/256 intepolation.
So if you select 1/16, it will internally divide them to 1/256 giving finer motion.

However, that may not be needed at all.

It depends on your steps per degree, as well as your pixel scale (focal length and camera sensor).
If steps per degree is high enough, and/or pixel scale is coarser, then it does not matter if it is a TMC or LV8279 (or S109 for higher amps).
If steps per degree is is low, and/or pixel scale is finer, then the TMC may have an edge due to interpolation.

I am using a fine pixel scale (0.47"/pixel = 1310 mm focal length and Canon T4i/650D) with 28,800 steps/degree, and the LV8729 performs beautifully. I could not detect any difference between it and the TMC2130 (other than silence).

If the Watterott brand is the preferred variety I’ll spend the money, although the link from the wiki is in a different currency than USD, not sure what they actually cost. The page also mentions BigTreeTech which seems to be pretty reasonable cost wise. Basically I’d want TMC2130 V3.0 with SPI and all of the pins on the bottom? (For price comparisons)
The eBay/AliExpress/Amazon non-Watterott drivers have been proven to work.
The problem is that there are many versions, some with SPI and some without.
Some have pins up only, some have pins up down only some have both up and down.
Some look like they have all what is required, but two extra pins show that they are SPI or not.
And depending on your board, you may need a certain.
Yes, there are too many variations, and yes, it is confusing, even to me.

Note that there is no shipping from China on many items.
I ordered a switch and did not get the shipping notice for about 10 days. I contacted the seller and they said the workers can't go to the warehouse. He will refund.


Re: TMC2130

Khalid Baheyeldin
 

On Thu, Feb 13, 2020 at 06:48 PM, Joe wrote:
I purchased a different set of GT2 gears for a better drive ratio on my Vixen GP. I had purchased a couple of the TMC2130s before doing research that unfortunately for me were the wrong version. I was unable to solder those really small jumpers on the bottom.
Soldering of these tiny components is very hard. Requires a steady hand, good eyesight, magnifier and experience.
Average people would like to avoid doing it, unless there is no other choice.

With the 3.16 OnStep release, if I’m reading correctly the correct driver would improve performance with using SPI? My question being is it enough of an improvement over the LV8729s to warrant buying them? 
SPI itself does not give an advantage.
What gives an advantage is all the Trinamic TMCxxxx drivers have 1/256 intepolation.
So if you select 1/16, it will internally divide them to 1/256 giving finer motion.

However, that may not be needed at all.

It depends on your steps per degree, as well as your pixel scale (focal length and camera sensor).
If steps per degree is high enough, and/or pixel scale is coarser, then it does not matter if it is a TMC or LV8279 (or S109 for higher amps).
If steps per degree is is low, and/or pixel scale is finer, then the TMC may have an edge due to interpolation.

I am using a fine pixel scale (0.47"/pixel = 1310 mm focal length and Canon T4i/650D) with 28,800 steps/degree, and the LV8729 performs beautifully. I could not detect any difference between it and the TMC2130 (other than silence).

If the Watterott brand is the preferred variety I’ll spend the money, although the link from the wiki is in a different currency than USD, not sure what they actually cost. The page also mentions BigTreeTech which seems to be pretty reasonable cost wise. Basically I’d want TMC2130 V3.0 with SPI and all of the pins on the bottom? (For price comparisons)
The eBay/AliExpress/Amazon non-Watterott drivers have been proven to work.
The problem is that there are many versions, some with SPI and some without.
Some have pins up only, some have pins up down only some have both up and down.
Some look like they have all what is required, but two extra pins show that they are SPI or not.
And depending on your board, you may need a certain.
Yes, there are too many variations, and yes, it is confusing, even to me.

Note that there is no shipping from China on many items.
I ordered a switch and did not get the shipping notice for about 10 days. I contacted the seller and they said the workers can't go to the warehouse. He will refund.


Re: Buying an EQ5

Chris Vaughan
 

Probably. We call it fly screen in Oz. 


TMC2130

Joe
 

I purchased a different set of GT2 gears for a better drive ratio on my Vixen GP. I had purchased a couple of the TMC2130s before doing research that unfortunately for me were the wrong version. I was unable to solder those really small jumpers on the bottom.
With the 3.16 OnStep release, if I’m reading correctly the correct driver would improve performance with using SPI? My question being is it enough of an improvement over the LV8729s to warrant buying them? 
If the Watterott brand is the preferred variety I’ll spend the money, although the link from the wiki is in a different currency than USD, not sure what they actually cost. The page also mentions BigTreeTech which seems to be pretty reasonable cost wise. Basically I’d want TMC2130 V3.0 with SPI and all of the pins on the bottom? (For price comparisons)


Re: Alignment / Slewing problems

Khalid Baheyeldin
 

On Thu, Feb 13, 2020 at 05:09 PM, Russ W wrote:
StellarJourney.com has all the commands listed, yeah?
I don't think the site is up to date with the exotic/obscure commands that are only used for debugging and such.

But I did try to use them once for backlash calculation. Didn't get that project completed.

For the RA axis
:GXF8#

For the DEC axis
:GXF9#

I do have a Python framework for OnStep if you are so inclined.


Re: Alignment / Slewing problems

Russ W
 

StellarJourney.com has all the commands listed, yeah?


Re: Questions about OnStep3.16

Howard Dutton
 

Note the issue had nothing to do with the Sun but rather that goto target (probably) happened to be East of the Pier and also south of the Celestial Equator.

I won't get into trying to detail every way the bug could be triggered before but there were many ways.  All taken care of now.


Re: Alignment / Slewing problems

Khalid Baheyeldin
 

We've had a discussion some time back about how to get OnStep
to calculate the steps per degree for you.

I can't remember the final solution we came with, and whether it
was a custom sketch, or just a series of LX200 commands to do
the same. There are some commands that can get the raw number
of steps.

But if you make the RA axis perfectly parallel to the horizon (using
a bubble level), then you can start with the DEC pointing to the
horizon as well, then tell it (in OnStep) to move 90 degrees. You
can measure both with a bubble level that has bubbles at right
angle to each other.

Anyone remembers?