Hi Stefano,
yes, you need a USB / Serial Converter with TTL Level.
Connect it to K3 on the Board. If it doesn't work, change the rxd/tyd pins.
Like this one
1pcs USB to RS232 TTL Converter Adapter Module PL2303 | eBay
yes, you need a USB / Serial Converter with TTL Level.
Connect it to K3 on the Board. If it doesn't work, change the rxd/tyd pins.
Like this one
1pcs USB to RS232 TTL Converter Adapter Module PL2303 | eBay
Meldano Motor Controller
SQ225917-Do you have any data on the motor controller? I had assumed it used DDS to generate the sine/cosine signals, but it appears to use PWM similar to the Music Hall Cruise Control. When you say 16 bit precision, I assume you mean the timer is 16 bit as I've never seen a 16 bit PWM in a µP before. What xtal is the µP using? It's hard to see how you could get accurate .01Hz resolution with an 8 bit PWM even running at 18.432MHz, the best I compute would be .05Hz (rounded down). Other than cost savings, I'm not sure why anyone would use PWM for an application like this. I've seen a number of DDS designs on this website, most of which use 24 to 32 bit devices. With the right xtal selection, you can achieve much higher resolution and absolute accuracy, i.e. limited only by the stability of the xtal rather than a rounded up/down approximation.
SQ225917-Do you have any data on the motor controller? I had assumed it used DDS to generate the sine/cosine signals, but it appears to use PWM similar to the Music Hall Cruise Control. When you say 16 bit precision, I assume you mean the timer is 16 bit as I've never seen a 16 bit PWM in a µP before. What xtal is the µP using? It's hard to see how you could get accurate .01Hz resolution with an 8 bit PWM even running at 18.432MHz, the best I compute would be .05Hz (rounded down). Other than cost savings, I'm not sure why anyone would use PWM for an application like this. I've seen a number of DDS designs on this website, most of which use 24 to 32 bit devices. With the right xtal selection, you can achieve much higher resolution and absolute accuracy, i.e. limited only by the stability of the xtal rather than a rounded up/down approximation.
Turntable Motor Torque
Stefano- If you use the dual phase output and get rid of the cap that normally created the phase shift, I think you will find that the motor has much more torque than before. On the power supply designs I've worked on, the cogging torque was easily 2x-3x when the dual phase connection was used vs single phase with a cap.
It also looks like the Meldano design ramps up the frequency for a "soft" start that would help mitigate the need for a lot of torque at start up. Not sure what frequency the controller starts at, but the Hurst motor on my VPI would not rotate below 20Hz (200 RPM) even with dual phase inputs to it.
Also the phase adjustment is only good for one frequency (speed). On one of the designs I was working on, the optimal phase difference was 93° for 45RPM (60 Hz) and 86° for 33.3 RPM (44.44 Hz). As SQ225917 pointed out, it is fairly critical and you can definitely find the sweet spot just by holding the motor (removed from the case) in your hand as you adjust the phase. It would have been nice if there were separate adjustments for each speed.
Stefano- If you use the dual phase output and get rid of the cap that normally created the phase shift, I think you will find that the motor has much more torque than before. On the power supply designs I've worked on, the cogging torque was easily 2x-3x when the dual phase connection was used vs single phase with a cap.
It also looks like the Meldano design ramps up the frequency for a "soft" start that would help mitigate the need for a lot of torque at start up. Not sure what frequency the controller starts at, but the Hurst motor on my VPI would not rotate below 20Hz (200 RPM) even with dual phase inputs to it.
Also the phase adjustment is only good for one frequency (speed). On one of the designs I was working on, the optimal phase difference was 93° for 45RPM (60 Hz) and 86° for 33.3 RPM (44.44 Hz). As SQ225917 pointed out, it is fairly critical and you can definitely find the sweet spot just by holding the motor (removed from the case) in your hand as you adjust the phase. It would have been nice if there were separate adjustments for each speed.
Very interesting. Does that mean that every time I switch from 33 to 45 I have to reprogram for different phase?
It is something it can be easily stored on EEPROM. Don't think it should be a big problem to make an update to the existing code. Are you sure it is not set up like this already?
Unfortunately I am very busy working on a couple of prototypes of my new gears so I haven't pulled the motor control together...so my apologize but I don't know how it works yet.
I work without vibration at 45 and 33 1/3 RPM and the same phase shift.
In my opinion the phase shift rectified the disposal of the coils in the motor.
And the disposal is at every time the same.
No one had problems in past with one phase shift for both speed steps.
But it is possible to programm a update for the pc app and the micro firmware.
In other case i think 2014 is a good year for a new design.
Actually I go the first steps with ARM Microcontroller. The ARM Controller Family have more speed for a higher resolution and dacs on board.
I think a ARM Controller is a good device for a new design.
Daniel
In my opinion the phase shift rectified the disposal of the coils in the motor.
And the disposal is at every time the same.
No one had problems in past with one phase shift for both speed steps.
But it is possible to programm a update for the pc app and the micro firmware.
In other case i think 2014 is a good year for a new design.
Actually I go the first steps with ARM Microcontroller. The ARM Controller Family have more speed for a higher resolution and dacs on board.
I think a ARM Controller is a good device for a new design.
Daniel
yes it wouldn't be a bad idea.
could you though, provide a simple update on the current controller? Then when you develop a new one with the ARM uC count me in, I want one.
I know the speed of the processor is higher and set of instruction optimized for a better/more efficient operation.
However before you will design a new one maybe since it will take a long time, it wouldn't be a bad idea to release this little update for the existing one.
What do you think?
could you though, provide a simple update on the current controller? Then when you develop a new one with the ARM uC count me in, I want one.
I know the speed of the processor is higher and set of instruction optimized for a better/more efficient operation.
However before you will design a new one maybe since it will take a long time, it wouldn't be a bad idea to release this little update for the existing one.
What do you think?
Yes, a new design based on a new controller will take a lot of time.
To program a update for the existing controller will also take a lot of time. O.K. not the same time like a new design.
I will take a look at the existing code for a solution... without promise...
Please note: In case of a new firmware you need a new controller from me and a pc app update. The code is not open source.
I think a update is not necessary to get a good motor controller
Because it is good 
Dan
To program a update for the existing controller will also take a lot of time. O.K. not the same time like a new design.
I will take a look at the existing code for a solution... without promise...
Please note: In case of a new firmware you need a new controller from me and a pc app update. The code is not open source.
I think a update is not necessary to get a good motor controller
Because it is good Dan
Yes, a new design based on a new controller will take a lot of time.
To program a update for the existing controller will also take a lot of time. O.K. not the same time like a new design.
I will take a look at the existing code for a solution... without promise...
Please note: In case of a new firmware you need a new controller from me and a pc app update. The code is not open source.
I think a update is not necessary to get a good motor controller
Dan
ahahah.....yes develop a new controller will take a lot of time. I do these kinds of things for living...so you are preaching to the quire!
If you make an update I only need the new hex code, I don't know if the programming header is onboard, but I can always simply put the uC on the breadboard and program it with my Atmel interface.
I think the update would be a nice plus to the current system
No pressure though.....
Daniel, I use two transformers to step up to 110v so maybe the greater vibration on the ' secondary speed' comes from that. I'm going to move to a 16v motor at some point I just need to find a precision pulley manufacturer.
I run my deck with thick silicon oil in the bearing for increased drag, the results I get for speed accuracy are already very good, as good as any deck from any manufacturer.
I run my deck with thick silicon oil in the bearing for increased drag, the results I get for speed accuracy are already very good, as good as any deck from any manufacturer.
I know, my english is very bad
No it's ok, your English is good.
That's ok, then I will purchase another pre-programmed MCU from you.
However, I don't understand what do you mean it is not open source code. If you send me the hex file, it's not like I can access the source code, nor would I have the time nor the interest to do that anyway
Moreover, the hex file is accessible on the microcontroller anyway if you have the interface in the first place.
This is where I fall short understanding what is the problem with the .hex file.
Anyway, I personally have no problem buying another uC from you if you update your code.
I think it would be a very neat feature as it allows to fine tune and optimize separately 33RMP and 45RPM.
I think the system you created is amazing and allows for great functionality and flexibility.
I can't believe all the motor controls, including the one I have from VPI, which are very expensive, don't deal with the dual phase.
why don't you get the 24V hurst motor like the one I am planning on getting?
What silicon oil do you use? Have you ever thought of running in IDLE having the motor touching your platter? That is something I am going to try as soon as I have finished my other developments.
I am only afraid for the vibration I might get from the contact of the pulley with the platter.
I didn't know there were pulley manufacturers. That's very interesting.
If you don't mind, can you share a pulley manufacturer you want to use with us?
I wouldn't mind re-doing my pulley as well.
