High Power UHU Thread (HP.UHU)

[contactirfu]

Hi Folks,

Just thought the we have different threads under the UHU thread so here it is.

The HP UHU thread

[mick22]

hello to all,
just been testing my board with motor and power for the first time,
no smoke yet! but i can't get the motor to stabilise.
when i switch the motor power on, the motor starts to run,if i do a reset the motor stops, then when i turn the shaft i can feel strong torque in one direction,but then the motor runs in opposite direction.

after 3 hrs of adjusting the p.i.d the closest i have come,is to have the
shaft stationary,but only torque in one direction.

The motor power 40v.
motor 70v 5amps with standard encoder conected to PINS A-6 B-4 ON J4.

JUST SPOTTED! SHOULD BE =A pin 5 ,B PIN 3.

is this my problem or is there something else.

can you please help. Regards, Mick.

[HJozsi]

Originally Posted by mick22 hello to all, just been testing my board with motor and power for the first time, no smoke yet! but i can't get the motor to stabilise. when i switch the motor power on, the motor starts to run,if i do a reset the motor stops, then when i turn the shaft i can feel strong torque in one direction,but then the motor runs in opposite direction. after 3 hrs of adjusting the p.i.d the closest i have come,is to have the shaft stationary,but only torque in one direction. The motor power 40v. motor 70v 5amps with standard encoder conected to PINS A-6 B-4 ON J4. JUST SPOTTED! SHOULD BE =A pin 5 ,B PIN 3. is this my problem or is there something else. can you please help. Regards, Mick.

Hi Mick,

as far as I remember I had also some problem using HEDS standard encoder with the SN75115N differential encoder, so I simple took it out an I put two wire 'jumper' into the Ic shocket for the A and B signal...

And please check the old thred :
DIY Servo controller

especially : #1890 05-01-2008, 06:14 AM tenmetalman

the partlists includes the latest changes regarding values some component...

I hope that helps ...Best regards,

Jozsef

[mick22]

Originally Posted by HJozsi Hi Mick, as far as I remember I had also some problem using HEDS standard encoder with the SN75115N differential encoder, so I simple took it out an I put two wire 'jumper' into the Ic shocket for the A and B signal... And please check the old thred : DIY Servo controller especially : #1890 05-01-2008, 06:14 AM tenmetalman the partlists includes the latest changes regarding values some component... I hope that helps ...Best regards, Jozsef

Jozsef,
thanks for your reply,

i tried removing the SN75115N and fitting jumpers,but still can't get
the shaft stationary with torque in both directions.

regards,
mick.

[H.O]

Hi Mick,
You say you have torque in one direction only. Is it completely "dead" in the other direction or do you have "some" torque but not as much as in the first direction?

I ask because I've expereinced both problems... ;-) At first I had no torque at all in one direction, this turned out to be a fabrication error on the PCB which resulted in the gate-drive signals being shorted to ground for one of the MOSFETs. There's more info in the old thread.

Then I had the problem with different torque depending on direction and this was cuased by the current limit circuit triggering due to noice, increasing C29 from 100pF to 470pF cured it on my test drive.

If you have a scope, look at the PWM output from the UHU-processor to see if it "tries" to apply torque in both directions, then look at the outputs from both IR21844 driver chips and see if you have drive signals to the MOSFETs.

HTH
/Henrik.

[mick22]

Originally Posted by H.O Hi Mick, You say you have torque in one direction only. Is it completely "dead" in the other direction or do you have "some" torque but not as much as in the first direction? I ask because I've expereinced both problems... ;-) At first I had no torque at all in one direction, this turned out to be a fabrication error on the PCB which resulted in the gate-drive signals being shorted to ground for one of the MOSFETs. There's more info in the old thread. Then I had the problem with different torque depending on direction and this was cuased by the current limit circuit triggering due to noice, increasing C29 from 100pF to 470pF cured it on my test drive. If you have a scope, look at the PWM output from the UHU-processor to see if it "tries" to apply torque in both directions, then look at the outputs from both IR21844 driver chips and see if you have drive signals to the MOSFETs. HTH /Henrik.

hello Henrik,
no it is not completely dead, infact it is possible to get torque in
both directions,but not when the settings have been adjusted to make the
rotor stop after a reset.

i have had a situation where reseting toggles the direction of rotation.

no i dont have a scope.
thanks, mick
Henrik,
there are no step and dir signals connected yet,could this have
anything to do with it.
regards.

[contactirfu]

are you using the Gxxx for moving the motor, then even I find that sometimes the motor does not move, I think its programmed to behave that way!

well try connecting the step and direction signals and the motor will turn.

RGDS
Irfan

[mick22]

Originally Posted by contactirfu are you using the Gxxx for moving the motor, then even I find that sometimes the motor does not move, I think its programmed to behave that way! well try connecting the step and direction signals and the motor will turn. RGDS Irfan

thanks Irfan,
my problem is getting the rotor to stop, with torque in both
directions.
regards, mick.

[kreutz]

Originally Posted by mick22 thanks Irfan, my problem is getting the rotor to stop, with torque in both directions. regards, mick.

Hello;

If the rotor moves in the wrong direction when applying torque, you should reverse the motor cables. If it oscillates around the rest position you should work on the motor tuning (PID). If it moves in both directions but does not stop, it is getting noise on the step/dir signals, there is a problem with the encoder signals, or there is a problem with the output stage Mosfet driving, as pointed out by Henrik.

Regards,

Kreutz.

[mick22]

Originally Posted by kreutz Hello; If the rotor moves in the wrong direction when applying torque, you should reverse the motor cables. If it oscillates around the rest position you should work on the motor tuning (PID). If it moves in both directions but does not stop, it is getting noise on the step/dir signals, there is a problem with the encoder signals, or there is a problem with the output stage Mosfet driving, as pointed out by Henrik. Regards, Kreutz.

Kreutz,
many thanks for pointing me in the right direction,
all i have to do now is find the courage to mess with the board.
cheers, mick.

[mick22]

Hello to all,
after my partial success with this board i have smoked the
output , luck'ily the board is ok, now i'm back to reading the old posts.

could someone please tell me, how important is height of R37,R36,R29 &R23
above the board surface, mine are way below .15",could this be my trouble.?

regards mick.

ps
i'm now the proud owner of a scope,so maybe will be able to stop the smoke!,

[HJozsi]

Originally Posted by mick22 could someone please tell me, how important is height of R37,R36,R29 &R23 above the board surface, mine are way below .15",could this be my trouble.? regards mick.

Hi Mick,

regarding my experience, it is more important the proper current limit...

regards,

Jozsi