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MKS GenL Serial1 Fix

John Petterson
 

Hi all,

I have never been one to accept being told I cannot do something.  Seeing the note in the wiki that the MKS GenL board could not use Serial1 because of some additional circuitry lit off a challenge bell in my head.

It turns out that there is additional circuitry that is explicitly designed to limit the use of those data lines to signals that change infrequently - limit switches on the Z axis of a 3D printer.  So these change once every few minutes or hours, and the circuit is designed to prevent quick blips from getting through.

Obviously for an ethernet or Wifi port, that is bad.

The attached PDF explains the circuit, shows how to fix it (very simple but very tiny parts and connections involved!)  I have successfully modified a V1.0 board, and plan to do a V2.0 board next week when my spare will arrive.

Regards,
John

Ant No
 

Although very tiny parts are beyond me it's pretty good you've been able to expand the usability of the standard board.

Not sure you really need to with more capable boards being so cheap now but I appreciate the use what you've got spirit

It adds another layer of satisfaction to the creative achievement we all feel when we make things for ourselves.

Well done.

Ant👣👣

PS. There's also the issue of yet another variant for the code to deal with. Is this something that just involves the config file and will run on standard code?


On 17 May 2020 02:42, "John Petterson" <j.petterson@...> wrote:

Hi all,

I have never been one to accept being told I cannot do something.  Seeing the note in the wiki that the MKS GenL board could not use Serial1 because of some additional circuitry lit off a challenge bell in my head.

It turns out that there is additional circuitry that is explicitly designed to limit the use of those data lines to signals that change infrequently - limit switches on the Z axis of a 3D printer.  So these change once every few minutes or hours, and the circuit is designed to prevent quick blips from getting through.

Obviously for an ethernet or Wifi port, that is bad.

The attached PDF explains the circuit, shows how to fix it (very simple but very tiny parts and connections involved!)  I have successfully modified a V1.0 board, and plan to do a V2.0 board next week when my spare will arrive.

Regards,
John

John Petterson
 

Ant,

There were no required changes to the config file or software. It uses the standard Serial1 connections.  After making those hardware changes it just worked.

I had not really realized how much faster the other boards / processors are.  I also could not figure out how to order any of the other circuit boards (the web site says minimum order quantities are in the neighborhood of 50 and I do not have nearly that many mounts), and did not want to wire one by hand on a perfboard.  If someone can let me in on the secret to order those, I would be interested in replacing the MKS board with either a Teensy 3.2 or 4.0.

John

On 5/20/2020 3:44 AM, Ant No wrote:

Although very tiny parts are beyond me it's pretty good you've been able to expand the usability of the standard board.

Not sure you really need to with more capable boards being so cheap now but I appreciate the use what you've got spirit

It adds another layer of satisfaction to the creative achievement we all feel when we make things for ourselves.

Well done.

Ant👣👣

PS. There's also the issue of yet another variant for the code to deal with. Is this something that just involves the config file and will run on standard code?


On 17 May 2020 02:42, "John Petterson" <j.petterson@...> wrote:

Hi all,

I have never been one to accept being told I cannot do something.  Seeing the note in the wiki that the MKS GenL board could not use Serial1 because of some additional circuitry lit off a challenge bell in my head.

It turns out that there is additional circuitry that is explicitly designed to limit the use of those data lines to signals that change infrequently - limit switches on the Z axis of a 3D printer.  So these change once every few minutes or hours, and the circuit is designed to prevent quick blips from getting through.

Obviously for an ethernet or Wifi port, that is bad.

The attached PDF explains the circuit, shows how to fix it (very simple but very tiny parts and connections involved!)  I have successfully modified a V1.0 board, and plan to do a V2.0 board next week when my spare will arrive.

Regards,
John


Howard Dutton
 

On Sat, May 16, 2020 at 06:42 PM, John Petterson wrote:
The attached PDF explains the circuit, shows how to fix it (very simple but very tiny parts and connections involved!)  I have successfully modified a V1.0 board, and plan to do a V2.0 board next week when my spare will arrive.
Though I doubt most MKS users will want to tackle this if you are ok with it we can store the PDF in the files section and link to it from the Wiki.

I wonder if it is necessary to remove those resistors which then must be bridged... perhaps just cut away the cap and pullup resistor and it'll all just work.  Is there room to do this without destroying those series resistors?

John Petterson
 

One would think I would have learned not to type a long response into a web page years ago…  Typing again into word and I will paste this response in and send immediately this time.

I would be honored to see that PDF saved on the web site.  I specifically submitted it in that format in case you deemed it worth posting.  I will also modify the next board with the resistors left in place and report on the results, and revise the PDF if it works. With some care I think it can be modified that way, and those resistors may not interfere with the data signal with the cap and pull up voltage gone.

I had the GM8 / Onstep outside for the first time last night.  Overall I was pleased.  After a quick polar alignment and one star alignment on the Onstar software, I was able to goto multiple targets and had them within the center third of a 9x60 finder scope each time.  Tracking was excellent – the targets never moved from the center of a 10mm eyepiece in a C8 OTA.  I can’t wait to get a camera on a scope on that mount now.

I have the switchable Wifi and ethernet combination we discussed earlier.  Both networks work fine, selecting either one before turning the power on puts that connection in service.  I have not tried changing without turning the Onstep off, but there is not a good reason to change that mid session.  I do wish that the Ascom driver window had an option to return the mount to home like the phone app does.  Having to pull out the phone to home the mount is a bit of a pain.

I did have some issues trying to use both an iPad for target selection and goto command, and then the phone with either the Onstep app or the web link to center the target.  The phone would not work using either of those options.  I had to use the iPad to center the target after the goto.  Is it supposed to be able to run both connections at the same time?  The ethernet is the 5500 mini board, and the Wifi is your recommended Wemos board.  I will do a bit more testing and provide more exact feedback on what is happening, tonight I was just enjoying seeing it work.  I guess I will have to build a hand controller to do that centering.  Did I mention that the tracking was perfect?

I will get a formal writeup with pictures of the build for your site.  I am using an MKS Gen L 2.0 board with TMC2130 drivers, .9 degree 2.0A 65 oz-in NEMA 17 motors, 4 to 1 (15 tooth to 60 tooth) belt drive, 12v to 24v step up voltage convertor that can be switched off in case of using it in a 12v only mount, Ruland jaw type couplers, and a bunch of 3D printed parts.  It all fits inside a box that mounts in the standard Losmandy footprint for controllers.

John

Howard Dutton
 

On Wed, May 20, 2020 at 11:34 PM, John Petterson wrote:
I have the switchable Wifi and ethernet combination we discussed earlier.  Both networks work fine, selecting either one before turning the power on puts that connection in service.  I have not tried changing without turning the Onstep off, but there is not a good reason to change that mid session. 
Good.

I do wish that the Ascom driver window had an option to return the mount to home like the phone app does.  Having to pull out the phone to home the mount is a bit of a pain.
Use the website on your PC.

I did have some issues trying to use both an iPad for target selection and goto command, and then the phone with either the Onstep app or the web link to center the target.  The phone would not work using either of those options.  I had to use the iPad to center the target after the goto.  Is it supposed to be able to run both connections at the same time?  The ethernet is the 5500 mini board, and the Wifi is your recommended Wemos board. 
Generally speaking yes more than one application should work if using port 9999.  If using port 9998, one at a time.  My App and ASCOM driver have error correction protocol support.  If using IP I always enable ec, it improves the latency of some commands and corrects some errors that might occur (not all though.)

Also keep in mind that the Mega2560 is slower than any other platform.  Two or three connections at once always seems to work fine here in testing.

Ant No
 

Hello John

If you are considering an upgrade the ESP32 is tremendous bang per buck unless you really need the extra pins the teensy provides at a price. It would be a huge step up from an Arduino.

I don't know which board manufacturer you were looking at but most of them have a minimum order of five boards now.

First step is to ask if anyone here has a spare board to sell, because they bought five.

If that fails buying five is usually not tooo dear and you can offer any spares for sale here to others in your position.

Ant👣


On 21 May 2020 11:31, "Howard Dutton" <hjd1964@...> wrote:
On Wed, May 20, 2020 at 11:34 PM, John Petterson wrote:
I have the switchable Wifi and ethernet combination we discussed earlier.  Both networks work fine, selecting either one before turning the power on puts that connection in service.  I have not tried changing without turning the Onstep off, but there is not a good reason to change that mid session. 
Good.

I do wish that the Ascom driver window had an option to return the mount to home like the phone app does.  Having to pull out the phone to home the mount is a bit of a pain.
Use the website on your PC.

I did have some issues trying to use both an iPad for target selection and goto command, and then the phone with either the Onstep app or the web link to center the target.  The phone would not work using either of those options.  I had to use the iPad to center the target after the goto.  Is it supposed to be able to run both connections at the same time?  The ethernet is the 5500 mini board, and the Wifi is your recommended Wemos board. 
Generally speaking yes more than one application should work if using port 9999.  If using port 9998, one at a time.  My App and ASCOM driver have error correction protocol support.  If using IP I always enable ec, it improves the latency of some commands and corrects some errors that might occur (not all though.)

Also keep in mind that the Mega2560 is slower than any other platform.  Two or three connections at once always seems to work fine here in testing.

John Petterson
 

On Thu, May 21, 2020 at 03:31 AM, Howard Dutton wrote:
Generally speaking yes more than one application should work if using port 9999.  If using port 9998, one at a time.  My App and ASCOM driver have error correction protocol support.  If using IP I always enable ec, it improves the latency of some commands and corrects some errors that might occur (not all though.)

Also keep in mind that the Mega2560 is slower than any other platform.  Two or three connections at once always seems to work fine here in testing.

I just checked, both the Android Onstep app and the iPad Sky Safari app are set up to use port 9999.  The web browser access I simply put in the 4 tuple IP address (192.168.8.110) - do I need the :9999 there as well?

I will do some more testing inside tomorrow.
John

Khalid Baheyeldin
 

On Thu, May 21, 2020 at 10:49 PM, John Petterson wrote:
I just checked, both the Android Onstep app and the iPad Sky Safari app are set up to use port 9999. 
Those can co-exist simultaneously, since port 9999 closes the connection after each command.

The web browser access I simply put in the 4 tuple IP address (192.168.8.110) - do I need the :9999 there as well?
No.
The web page is on port 80, which is the default port for the world wide web, so just:

http://192.168.8.110/ 

Should simply work, assuming you set it up to connect to your home's WiFi access point, and the x.x.8.x is the subnet assigned by it.

John Petterson
 

I ran the mount a bit today.  All good now that I understand it. I am putting together a checklist card, if anyone has suggestions about what else should go on this let me know.

1) Set up tripod, add the GM8.
2) Polar align using the alignment scope.
3) Add counterweights, then add scope and camera or eyepiece and balance it.
4)  Select Onstep options - Wifi or ethernet interface, 12V or 24V motor option.
5) Turn on all of the electronics.
6) Using phone app, load location and then time.
7) Do an alignment process (number of stars optional).  Start it on the phone app, use simple hand controller to center and accept alignment.
8) Link either (or both of) Cartes du Ciel on the PC or Sky Safari Pro on the iPad.

I went through this earlier.  After connecting both apps, I could do a go to from either of the two devices or command a move on the hand controller, and both screens would track the scope location. The mount happily moved around on command, and then tracked the final target for a couple of hours.  This was indoors, so I cannot attest to the accuracy.  Then I ordered a return to home on the phone, and shut down after verifying both applications showed the scope pointing north.

Right now I am watching dark clouds rolling in.  Probably no chance to get this outside tonight.

(Note for number 4 above: Both of the options mentioned are switch selectable on my Onstep.  I have a small wireless and hard wire router on the tripod with a mini PC running there too.  I have both that mini wireless router and the Wifi in the Onstep configured so that the Onstep is at the same IP address regardless of which interface I am using.  Since only one can be on in the Onstep at a given time, there is no chance for any confusion, but also no need to worry about changing configs - just connect to the Wifi that the mount is using and run.)

John