DIY BLDC / DC Motor Servo Drive - ARM MCU (STM32F103C8T6)

[mcm_xyz]

Hi,
the 6N137 has a inverted logic. I orderd the HCPL3180 from China for 1$. I do not know about the quality, when I receive them I will test.

Hans

6n137-I, seems to be half price (half frequency also) and positive output, but I do not think we need that super speed. We have only 20kHz in PWM speed... (wanna change that? )
http://www.tme.eu/ro/Document/71c7b9...e816/6n137.pdf

Mihai

[mcm_xyz]

HCPL3180 is mosfet gate drive opto, you can direct drive mosfet
gud choice

I must admit I do not get this very well... You mean we could use a couple of those to drive directly the low and high side of a half bridge without using any other dedicated circuitry? How do they work? We do not need a Higher voltage for high side?
Hmmm... I do not get it... please elaborate with a schematic... could we drop the ir2101s?

Thanks

Mihai

[mcm_xyz]

I must thank here to the user tivoidethuong who offered to give me for free a DC motor for testing. Thanks again! I appreciate it. You can make a special request for the code ))
I just bought from ebay a used servo. Dunkermotor GR42x25 mit Getriebe PLG 32, i=6,25:1, 12V-24V/DC, 3600 U/min | eBay
I think it will do just fine for our DC motor testing. I will add DC motor support after I will receive it... I presume nothing will change in the schematic... so go ahead with your designs...
Please do not forget to add a jumper from PB1 to 3.3V for the bootloader...

Mihai

[mcm_xyz]

Hi Mihai,
maybe I can build the pcb some smaller, but I will produce the prototype with isolation milling. I think the power-pcb is 100 x 60 mm, so both parts has europaformat. Can the Arm reads a thermoelement type K directly, is there a internal multiplicator for the analog inputs build in? Its possible to program an outputpin to enable the integrated powerbridge. I have orderd the optos in China and they are very inexpencive. Quality?

Thanks

Hans

I do not think we can add the type K termo sensor directly to the ADC.
From what I understand from this picture: https://en.wikipedia.org/wiki/Thermo..._functions.svg
we have a variation of 10mV for 250 Celsius... our ADC is 12 bit with VRef set to 3.3, so this gives us o theoretical resolution of 3300 mV / 4096 = 0.71 mV... not very good for measuring a few milli Volts... So we need to amplify that signal...

Mihai

[tivoidethuong]

about opto mosfet gate drive
1. bostrap like ir2101


2. independent 15V voltage source for high side

[Holzwurm56]

Hi,
if its not possible to read the K-sensor directly with the Arm it will be not a problem to insert a special operationamplifier ic. I do not know the manual from the ARM but some microprocessors have integrated programmable gain for some of the analog inputs. For the power pcb I will use a integrated bridge IRAMX20up60a there the mosfetdriver built in.

Hans

[tivoidethuong]

Hi,
if its not possible to read the K-sensor directly with the Arm it will be not a problem to insert a special operationamplifier ic. I do not know the manual from the ARM but some microprocessors have integrated programmable gain for some of the analog inputs. For the power pcb I will use a integrated bridge IRAMX20up60a there the mosfetdriver built in.

Hans

if you are use iramx20up60a, i dont think HCPL3180 suitable
6n137 is good choice

opto for direct mosfet gate drive
Isolated Gate Drive Optocouplers

opto for IPM interface
IPM Interfaces

about positve ON or negative ON, you can modify stm32 code

tivoi

[mcm_xyz]

Hi,
if its not possible to read the K-sensor directly with the Arm it will be not a problem to insert a special operationamplifier ic. I do not know the manual from the ARM but some microprocessors have integrated programmable gain for some of the analog inputs. For the power pcb I will use a integrated bridge IRAMX20up60a there the mosfetdriver built in.

Hans

From what I know there is no way to set the gain in the STM32F103 ADC (old ATMega644 that I am familair with had such features). And since we need the Vref to be at least 3.3 V in order to measure the used current as good as possible we can not decrease Vref. So you need to boost the signal from the K Thermo in order to measure it good. But by the way... Do you intend to something with the value measured like limit the current and stuff? or you just want to stop the circuit on overtemperatures?

Mihai

[Holzwurm56]

Hi Mihai,
only stop at overtemperature. This feature must not work from the first time, but its easier when its possible in the pcb.

Hans

[Stigoe]

Instead of trying to read the thermocouple directly or trying to make an amplifier to be able to read it, wouldn't be easier to just use a MAX31855K chip?

[mcm_xyz]

Instead of trying to read the thermocouple directly or trying to make an amplifier to be able to read it, wouldn't be easier to just use a MAX31855K chip?

Let's keep things simple please...

Mihai

[tivoidethuong]

i recommend use dido for temp protec

Capgo - Semiconductor Temperature Sensors

[James Newton]

The TIL191 and TIL192's appear to be obsolete... Does anyone know a current part number? I'm trying to figure out the total BOM cost.

[jalessi]

James,

I believe Newark still has the TIL191:

TIL191 - Buy ISOCOM TIL191 Online at Newark element14

Jeff...

[James Newton]

James,

I believe Newark still has the TIL191:

TIL191 - Buy ISOCOM TIL191 Online at Newark element14

Jeff...

Is there no modern replacement? Should we be making new designs based on chips that are becoming difficult to source?

[tivoidethuong]

i thinks til191 can replace by pc817
http://www.sharpsma.com/webfm_send/1092

[Holzwurm56]

Hi,
here is my next pcb from the controlpcb. I hope the thermosensor type K can connect to the opamp. For current sensing the arduino isolated modul can be used. The power pcb comes soon, I will it use for variable frequency drive and the servo drive. The vfd is a project in the german microcontroller forum.
ServoCont2.jpg
Hans

[Holzwurm56]

Hi,
here is my first design from the power pcb. Hi Mihai its possible to use a pin from the to switch the power bridge on or shut down?
ServoPower.jpg

Hans

[mcm_xyz]

Hi,
here is my first design from the power pcb. Hi Mihai its possible to use a pin from the to switch the power bridge on or shut down?
ServoPower.jpg

Hans

Sure thing Hans. Any other free pin can be used as GPIO. What pin would be good for your design?

Mihai

[Holzwurm56]

Hi Mihai,
I think B0, B1, B10 or B11.

Thanks

Hans