[xcad]

Hi Max,
I have a couple of questions about the code in YAPSC_MERGED. They are probably pretty dumb but I like to understand how things work!

In timer1.c line 89 cmd_posn is set to POSCNT+1. Why +1?

Step and direction inputs use input capture ISRs (IC1 and IC2). I am thinking of using CN0 (pin 12) for direction change and T2CK (pin 11) to count on every edge for step input (need to change UART to pins 17 and 18). This would eliminate ISR overhead on step pulse. Counter would be used to update cmd_posn and be cleared on direction change and in servo loop interrupt.

What do you think of this? I do not have a lot of experience coding dsPIC!

What are the differences between DEMOBOARD and YAPSC V1

It seems that pwm.c is set up for all n channel mosfet h-bridge and for high-side p channel mosfet I should change high-side output polarity to active low. Is this correct?

Many thanks for your consideration.

[MaX-MoD]

Hi Xcad,

Honestly I don't remember why I put POSCNT+1. I know I had to do so to fix an offset problem but I have not kept a trace of this problem so I won't be able to explain it.
maybe I'll have some time to look back at it this week end.

The step and dir inputs would probably work with the timer input and the CN pin.
Although I investigated this solution at the beginning I didn't kept it because
1) the original code from Glaister was using quadrature input; it's still possible to revert the STEP/DIR change back to quadrature if required
2)I found little use of it cause I could get a lossless 1MHz (!) STEP input
3) I wanted to have the PGx lines and UART accessible at the same time, MUCH easier while debugging
4)Timing. Checking the DIR line status in the STEP ISR gives easier STEP to DIR timing much more forgiving.

Concerning "hybrid" P&N H-bridge, well "active" means "the associated transistor is blocked and current passes trough it"
Depending on your driving circuit you may have to change the PWMxH output polarity, but not necessarily.

Hope I've helped

Best regards
Max

PS:
Demoboard has some differences with the actual V1 PCB, including reversed STEP and DIR inputs. The #defines are here to handle this easily.
for V1 PCB, use none of #define DEMOBOARD nor #define YAPSC10V.

[xcad]

Hi Max,
Thanks for the reply. I hadn't thought of the PGx and debugging issue - good point.

I will have to change high-side polarity. For interest I have attached circuit diagram of my h-bridge; should be good for about 90v 10 amp. My test board shows nice clean output on the scope.

Best regards

[Roberto_c]

hi, me need help.....
I have realized a card for YASPC v1 but I have some problem.
When I give power the motor it is free in a sense and jammed in the other sense, I don't understand how come, help

hi

[Iron-Man]

Check out Max-Mods work at http://www.cnczone.com/forums/showthread.php?t=74532

Please provide more information, pictures of your set-up etc. Post to the link above. Max will be able to provide better information on the YAPSC.

Iron-Man

[MaX-MoD]

Hi,

generally the motor behaves this way if you have fried MOS or gate driver.
Possible too is that you have a bootstrap capacitor too small.

Also I've seen something a bit annoying on one board, very high parasitic sensitivity (indeed, conduced parasites from the H-bridge). I think it depends on the optocouplers brand. In fact you can see on YTT that even thought the STEP input is disconnected, the command from PC keeps on augmenting as the motor turns.

You can try adding a MKP/ceramic 0.1uF capacitor soldered directly between pins 5 and 8 of the optos (the power supply)
For that special board it solved the problem.

BR & GL
Max

[marcosinatti]

Hi,
Very good project, my compliments!!!
I want to make it, but i have some IR2184 and i have not IR2101.
The IR2184 have only one pwm input and it have two output, one direct and one inverted.
It's possible use it, if I connect only two dspic's pwm outputs (only the two high sides for example)?

Sorry for my bad english!

Thank You
Marco

[MaX-MoD]

errr

tell me if I'm wrong but seems to me that when turning ON the P mosfets current will flow from +48V (90V?) into D5, R4 and U2 to the ground.
So there will be 48-12 = 36V at the 100Ohms resistor leads. This resistor dissipates 12.96W...
Why are you using P mosfet instead of N mosfets? The IR2110 is a bootstrapped driver so a simple scheme like this will do:
Just keep the PWM output in the 0-99% range for the bootstrap cap to recharge and it's all right

[Iron-Man]

Max

Are you looking for a ready built unit or do you want to design from scratch?
I found this on ebay.
http://cgi.ebay.com/LOT-3-POWER-ONE-...item414adc4fc2

Also, check this out, http://www.mpja.com/prodinfo.asp?number=18074+TR

It is not isolated, but with a few components it would make a great HV DC power supply.

Hope this helps.

Iron-Man

[xcad]

Sorry Max, attached the wrong file version. I "discovered" the TVS mistake with some magic smoke in the first prototype. Correct file attached. I am using the Ps because I had a supply of them and high-side only switches on direction change so switching losses and speed not big problem.
Best regards

[xcad]

Hi Max, another question; this time about PWM setup. I cannot see where the mode is set in the PTMOD bits of PTCON. At reset they are set to 00 which is free running mode so I assume this is the mode the module remains in in the setup. Is this assumption correct?

Looking at the code for function set_pwm (), I cannot work out how the upper opposite leg of the h-bridge get turned on. It appears that each pin pair is set to complimentary mode and depending on the state of temp_dir either is toggled according to the associated PDC setting or off (PDC set to zero). May be that the circuit has different connections but I cannot see from the code how, for example PWM_PIN2H and PWM_PIN3L are turned on together to drive a motor connected to the legs of an h-bridge. Can you explain what I have missed? May be I am not understanding what complimentary mode really means.
Many thanks
Best regards

[MaX-MoD]

Thanks for the link iron-man!
I'm designing the PSU myself. I plan on doing 120-200V adjustable PSU with overvoltage, overcurrent and overpower limit. 1KW or more.
Thought it will take some time, I'll learn some more on High-Power electronics


Hey xcad!
The new schematics are much better!
except for R7 and R8.
If the 48V is fed but not the IRF power, R7 and R8 will put both Q3 and Q4 ON state. The problem is also that the VDS voltage will be equal to the threshold VGS. It can cause some serious problems in some cases.
The best is to remove them.

There is another thing you have to consider:
The bootsrtrap cap dischanges itself. If the BS cap is discharged, the higher MOS are turned OFF.
To avoid this, you have to switch the high side MOS to OFF from times to times to allow the BS cap to recharge.

the proper PWM operation is the following:
0% PWM = "lower MOS turned ON and higher MOS turned OFF"
100% PWM = the opposite.

You cannot go over 95-99% PWM otherwise the BS cap will discharge.

So, to choose the output polarity, one bridge is at 0%PWM (ie 0Volts) and the other is 0-95% PWM (0-95% * 48V).
To reverse the polarity, swap the two PWM values.

This is what being done in PWM.C. First is to determine the output polarity required:
If positive, feed PWM2 with 0 (0% PWM = 0V) and PWM3 with le PWM output wanted.
If negative, same but reverse PWM2 and PWM3.

Il PWM.C, line 108 is

    PWMCON1 = (PWM_MOD1_COMP & PWM_MOD2_COMP & PWM_MOD3_COMP &	// complementary outputs

these are helper #defines for the PWM configuration:
PWM_MODx_COMP means "PWMx is set for complementary PWM"

is it OK now?

best regards,
Max

[MaX-MoD]

Yes. /SD pin should be at 0V then.

good luck.

Max

[irxplod]

is this controller for a BLDC motor or Brashed ?

i search for a Brushless dc or Ac Motor Contoroller .

[visky]

is this controller for a BLDC motor or Brashed ?

i search for a Brushless dc or Ac Motor Contoroller .

It is for Brashed motors.

[adisak]

[ame="http://www.youtube.com/watch?v=6XbgN3uNVdw&feature=endscreen&NR=1"]http://www.youtube.com/watch?v=6XbgN3uNVdw&feature=endscreen&NR=1[/ame]
dspic30f4011 LCD 16x2 DISPLAY
encoder 1000 p/r
lcd Show
x feedback eencoder
c command from pc mach3 cnc sof

[dwalsh62]

As much as I like the idea of open-source hardware/software, I am greatly disappointed in the lack of an inexpensive funcitonal DC servo driver.

Don't get me wrong, there have been some interesting designs posted and some that appear to have merit (roverto_c's Schema.zip needs minor mods like schottky diodes diodes) but all seem to be incomplete, some missing source code, others have strange power supply requirements (OPA549).

Those who have offered such designs like Iron-Man and Max-Mod have all vanished making obtaining a reliable working design impossible.

I'd really like to find a working solution that targets the electrocraft E240/G240 type DC servo motors since they are plentiful, include an A/B/Z encoder and run from +48volts but like many, luck is not on my side as no solution seems to exist.

If someone has a proven design I'd really like to consider it so contact me please.

-- Dale

[Iron-Man]

As much as I like the idea of open-source hardware/software, I am greatly disappointed in the lack of an inexpensive funcitonal DC servo driver.

Don't get me wrong, there have been some interesting designs posted and some that appear to have merit (roverto_c's Schema.zip needs minor mods like schottky diodes diodes) but all seem to be incomplete, some missing source code, others have strange power supply requirements (OPA549).

Those who have offered such designs like Iron-Man and Max-Mod have all vanished making obtaining a reliable working design impossible.

I'd really like to find a working solution that targets the electrocraft E240/G240 type DC servo motors since they are plentiful, include an A/B/Z encoder and run from +48volts but like many, luck is not on my side as no solution seems to exist.

If someone has a proven design I'd really like to consider it so contact me please.

-- Dale

I have not vanished. If anyone is interested please contact me. the OPA549 is an operational amplifier and requires a split power supply. If anyone has interest then please let me know. Yes there are a lot of projects out there, but for high performance something other than a dspic or ARM STM32F type processor is needed. I have used the DsPic servo amps to mill all the conversion parts for the Denford NovaTurn Lathe and the parts for the AMD Gizmosphere 1 enclosure. You can see my work posted on CncZone and the Denford web sites.
For serious applications, Texas Instruments processors should be looked at. AC Servo Drives | TI.com. They are high performance and have software for most motor designs, DC, AC, BLDC servos etc.

I have gathered components and info for a upgrade to the OPA549. It is a TLE 6209 R (Delivers up to 6 A continuous and 7 A peak current, Operates at supply voltages of up to 40V).
I could provide some help and circuit boards if the interest is high.

Currently busy upgrading the NovaTurn, iBOB2 and AMD GizmoSphere 1, PathPilot.

If anyone is interested please let me know.

Hope this helps,

Iron-Man

[epineh]

As much as I like the idea of open-source hardware/software, I am greatly disappointed in the lack of an inexpensive funcitonal DC servo driver.

Don't get me wrong, there have been some interesting designs posted and some that appear to have merit (roverto_c's Schema.zip needs minor mods like schottky diodes diodes) but all seem to be incomplete, some missing source code, others have strange power supply requirements (OPA549).

Those who have offered such designs like Iron-Man and Max-Mod have all vanished making obtaining a reliable working design impossible.

I'd really like to find a working solution that targets the electrocraft E240/G240 type DC servo motors since they are plentiful, include an A/B/Z encoder and run from +48volts but like many, luck is not on my side as no solution seems to exist.

If someone has a proven design I'd really like to consider it so contact me please.

-- Dale

The Elm Chan servo drive works well for the electrocraft servos, I have them on my router and have never had a problem.

ELM - DC Servomotor Controller

That is about as cheap as you can get for a DIY servo drive.

Another option is this one, that also does BLDC, I am going to try build one myself, time permitting...it is derived from the original dsPIC servo and MAX MODs version.

https://www.vbesmens.de/en/positioning-controller.html

Good luck.

Russell.

[James Newton]

The Elm Chan servo drive works well for the electrocraft servos, I have them on my router and have never had a problem.

ELM - DC Servomotor Controller

That is about as cheap as you can get for a DIY servo drive.

:cough:

http://www.cnczone.com/forums/open-s...en-source.html