[krazatchu]

Good to hear your killing it~~ lol

As for deadtime, the ir2184 does already have the built in 500ns...
At lower voltages with reasonably fast FETs, it's prolly enough as it is...

My motor voltage is 24 volts, and I'm running the supply at 30 volts dc
to compensate for not being able to have the top FETs on all the time..
The top FETs can't be 100% on since some time is required for the charge pump of the ir2184 to recharge...
I think you can find reference to that in the source code....

At higher voltages, or with FETs that have a higher gate capacitance,
you might want to add the circuit you pictured...
It will cause the FET to turn on slowly and turn off quickly...

Also note, some circuits use the ir21844, which has variable dead time...
Of course the deadtime could be programmed into the AVR as well...
Or the code ported to a TINY26 which has built-in deadtime on inverted outputs ...

As for the PSU, the first ELM-Chan board I made had a 7805 regulator...
The 7805 was the only component on the board that got hot...
Since then, I have developed a slight distaste for all things linear ...
As a result, I have be experimenting with switch mode buck and boost regs...
My most recent project, a data logging digital scale for my wife, uses a MAX710 boost regulator, it's nice but I think there are cheaper ones in the LT1XXX series...
It will be in the projects section at avrfreaks when it's completed (soon)...

Anyhoo, the downside of the PC PSU is lack of current limiting...
If something shorts, it will do so rather fantastically...
I think the 5 volt line on the PSU I'm using is rated for more than 25 amps...
Some low amp fuses on the board, separating the 12 volt and 5 volt lines from the board would be good practice...
I should have added them...

The negative supply form the PC PSU is very handy if using dual supply opamps....
Also there is 3.3 volts and standby power...

I built a power toggle with a cd4013 d-type flip flop to power on the PSU...
It get's its supply from the standby wire on the PSU...
I configured it so that one must press and hold the button for a second to turn on or turn off...
I should have built it into the break-out board but it was an after thought...
Attached is the power toggle circuit, looking at it now, I think I could have prolly used one of the spare inverters instead of the 2n2222 to reduce the part count a bit...
In is from the button, out is to the power wire of the 20pin PSU molex connector...

Heh~~ how's that for long winded ?? lol

Ciao!!
Michael

[ivancasten]

Greetings Michael,

Thanks for your detailed informative reply.
More to digest.
Intend using irf540's.
24 VDC @ 15 Amps with suitable heat sinking.
Your point on fuses well taken.

regards Ivan

[krazatchu]

24 VDC @ 15 Amps gives about 360 Watts...
That's a pretty big motor... especially for 24 volts...

Don't forget, you will need more than 24 volts, due to losses and the afore mentioned charge pump thingy...
You can also add a little extra to the supply voltage for those times you need a little extra "kick"...
Any over voltage can be de-rated with the tuning parameters, with an expected loss of resolution...

Of the motors I ran, the highest might have been about 150 watts @ 24 volts...
I ran it with some g code, unloaded for at least an hour...
I couldn't even notice a temperature change on the FETs...
I think they might have been the IRF540's, will check later...
And no heat sink on them...

The next design I do will use SMD Fets which still allow for heatsinks if nessecary...

If you are heatsinking, remember to get isolation pads between your heatsinks and FETs...
The tabs/cases of the high side and low side are at different voltages...

Ciao

[emilcnc]

Hello all,

To Ivancasten - sorry for late answer !
My attached chematics was posted to be approved, but contains some errors ! - sorry. I did wrong connection on TL084 ..

The good news - http://www.cnczone.com/forums/showthread.php?t=71083

Here is the thread about my servo - ELM CHAN + UHU power stage .. = BG DC SERVO ....

Please look at working PCB from this thread with disconnected current limiting part .... PCB.jpg ...

About questions related to zener and diodes on power stage - see the "to remove.JPG" - remarks to me ( to my design ) from friend, who knows why this is possible and necessary ! ( dont ask me )

If you need more info - please follow my thread and ask me there ..

Emil

[Rony.sn]

Hello everyone,

Been busy with al kind of houshold stuff.
But i was able yo redesign my board.
The layout should be ready for printing an used as film.
Right now i am testing some opto's , to find out wich one is the best.
Standard 6 pin type's , like TiL11, 4N27 etc.
At 25khz they are not able to produce a nice square signal at their output.
So stil looking for the right one.
Maybe one of you have suggestions ?
THX in advance



Rony

[krazatchu]

Hey...

The HCPL 2630 is a pretty standard opto for this kind of thing...
But it's an dual package 8 pin....

Ciao

[nhatson.elec]

Check this! This is exel calculation file I made.

Regards.

thanks your execl caculation

[ivancasten]

Hey...

The HCPL 2630 is a pretty standard opto for this kind of thing...
But it's an dual package 8 pin....

Ciao

Greetings or G'day,

Breakout Boards !!!
Also looking at.
As you said HCPL 2630 is pretty well the standard.
Not readily avail. in Au.
However the 6N137 is.
It seem to have the same performance as the HCPL 2630.
But a single package in an 8 pin.
The above may be wishful thinking on my part.

Regards Ivan

PS Michael, Emil & Rony thanks for your posts.
its how I'm learning

[krazatchu]

The Fairchild datasheet for the HCPL2630 also has the 6n137 ...
So it seems they are cut from the same cloth and should be identical in performance...

Ciao1

[epineh]

As you said HCPL 2630 is pretty well the standard.
Not readily avail. in Au.

Hi Ivan, I got my 2630's from Digikey, the price was reasonable and the shipping didn't hurt too much. The service is fantastic from them as well.

As mentioned the 6n137 is the same opto but a single channel version, I am thinking of using them once I run out of 2630's and as you would probably know Futurlec stock these.

Cheers.

Russell.

[Rony.sn]

Hello

Just finished etching a board.
Without planes and i wil use Til111 as opto.
Did some testing with different types i have aroud, and they perform better
than the 4Nxx types.
Since the Fan fet drivers have shmit trigger inputs , it should work.
Also added 2 extra transistors to swich the led's in the opto's , so the controller ports have almost no load to handle.
Drilling and placing components should be something for the weekend.
Keep you posted with results.

Rony

[Rony.sn]

Hi,

Assembled the circuit board , and have been able to do some testing.
After changing parameters, drive is stil very rough, it go to position
enterd via hyper terminal.
The comand + or - followed by a number of steps works.
So with opto's things go better , even with the motor jumping around,
the controller keeps alive.
That part should be ok now.
However , connecting a puls signal to the drive , has no effect.
Puls signal can be measured at the leg of the controller, and present.
Could be parameter settings , like puls multiplyer .
I wil try to load te Ivan code in the controller , but i can't seem to find
the correct function of the parameters with that code.
Have to do some searching on the forums?


Rony

[epineh]

Rony, for the original Elm code there is two versions, the original is labelled SMC and the newer version is SMC3/A, the newer is the one you want for servo use, I may have missed it but which version are you using ?

The older version has a few cool features like G00 commands via serial, I haven't used it though...

To put the drive into servo mode, give it a M3 command via serial.

The pulse multiplier is P6, set it to 256 for normal operation (no multiplier) (this is for the SMC3/A firmware)

Ivan's code is the same except for P7 which is the D value in the PID loop.

Hope this helps

Russell.

[mughal]

Sorry for not getting back to this, got the OK to post the source...enjoy

I changed the extension to .txt just in case you want to compile it yourself you will need to change this to .asm, but I guess you already knew that

Cheers.

Russell.

HI... I need .asm file of smc3amod3.hex file....please send me .asm file to my email [email protected]
i will be realy greatfull to u..

[mughal]

HI... I need .asm file of smc3amod3.hex file....please send me .asm file to my email [email protected]
i will be realy greatfull to u..

i have built a board with elm servo and burn smc3amod3.hex file in attiny2313 controller...it is working but i need to change the values of encoder to match my servo...kindly reply as soon as possible..
Naeem Mughal

[krazatchu]

mughal,

To change the parameters, you need to connect the drive to you PC serial port...
If you don't have a serial port, a USB to serial (rs232) converter will work...

You will also need a terminal program on the PC...
I use "Terminal v1.9 by Br@y" , but any terminal program will do...

Once you get it connected, power up the drive, and you will get a help menu on the terminal...

There are 8 parameters, p0 to p7 ...
To calculate the parameter values, follow this link, bottom half of the page, labeled "Online Command"...
http://elm-chan.org/works/smc/report_e.html

If your using SMC3a, then p6 is a step multiplier, just set it to 256....
If your using Ivan's version, then p7 is the "D" parameter of PID....
Ivan's version can be found a few pages back, posted by Russell...

Have fun....

[mughal]

mughal,

To change the parameters, you need to connect the drive to you PC serial port...
If you don't have a serial port, a USB to serial (rs232) converter will work...

You will also need a terminal program on the PC...
I use "Terminal v1.9 by Br@y" , but any terminal program will do...

Once you get it connected, power up the drive, and you will get a help menu on the terminal...

There are 8 parameters, p0 to p7 ...
To calculate the parameter values, follow this link, bottom half of the page, labeled "Online Command"...
http://elm-chan.org/works/smc/report_e.html

If your using SMC3a, then p6 is a step multiplier, just set it to 256....
If your using Ivan's version, then p7 is the "D" parameter of PID....
Ivan's version can be found a few pages back, posted by Russell...

Have fun....

Dear,
i don't know how to connect a drive with terminal...kindly guide me step by step how to connect and then change the parameters of the drive....please i m realy upset...i need to complete my project.
thank u so much
Naeem Mughal

[mughal]

mughal,

To change the parameters, you need to connect the drive to you PC serial port...
If you don't have a serial port, a USB to serial (rs232) converter will work...

You will also need a terminal program on the PC...
I use "Terminal v1.9 by Br@y" , but any terminal program will do...

Once you get it connected, power up the drive, and you will get a help menu on the terminal...

There are 8 parameters, p0 to p7 ...
To calculate the parameter values, follow this link, bottom half of the page, labeled "Online Command"...
http://elm-chan.org/works/smc/report_e.html

If your using SMC3a, then p6 is a step multiplier, just set it to 256....
If your using Ivan's version, then p7 is the "D" parameter of PID....
Ivan's version can be found a few pages back, posted by Russell...

Have fun....

can u please send me the ASM file of this version....will be realy thankful to you....
Naeem Mughal

[ivancasten]

G'Day All,
I maybe should have posted in Emil's new file.
However !
I noticed Emil has two 75176's on his new board "servo 1"
I'm trying to figure out how to use.
And what are the benefits.
See attached sketch for comment.
I used TinyCAD. Been trying to use Eagle ( Turkey comes to mind ie. the user)

Cheers Ivan

[krazatchu]

i don't know how to connect a drive with terminal...kindly guide me step by step how to connect and then change the parameters of the drive....please i m realy upset...i need to complete my project.

Did you follow the link? Did you read the page? http://elm-chan.org/works/smc/report_e.html

can u please send me the ASM file of this version....will be realy thankful to you....

Did you even read what I posted?

Ivan's version can be found a few pages back, posted by Russell...

Have fun....