[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]

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 :
http://www.cnczone.com/forums/showth...14217&page=158

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]

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 :
http://www.cnczone.com/forums/showth...14217&page=158

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]

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]

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]

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]

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!,

[contactirfu]

Me and paul are planning to have few more kits (limited) ready by mid August, interested folks may email uhu.highpower(at)gmail(dot)com,

the new kits have C19 and C23 tantalums caps rated at 35Vs, and the 0.1uF ceramics are replaced by all mylar caps.

it still stands beta!

[tenmetalman]

Hello All,
the following is a recap of information I sent to John D. earlier.
Be sure and read the trials Irfanulla & I've gone through and take advantage of his learning curve. To avoid seemingly random catastrophic drive failures be sure to build and use the Regenerative Power Dump & install the 4700uF electro 50vdc Cap & 1uF 50vdc caps in parallel with 15volt power supply. Also use 10uF 35vdc tantalum caps on C-19 &C-23 on the HP UHU drive. I can see I've fallen way behind on updating the parts list & build recommendations. We are still building on the Rev. "B" PCB. All need to be Building to Rev. "C" Parts plus the above special instructions. Driving servo's of over 100vdc & 10 amps WILL result in the above catastrophic failures, UNLESS ALL of the listed changes are implemented the failures will occur & appear random & will end up damaging all of your HP UHU drives. the RPD PCB's are fairly easy to make.
Good Luck to All
Paul

[mick22]

Hello everyone,
just got my board up and running ,after blowing the output.
Before i test with motor power 38v,would it be possible for someone to
post the waveforms that should be present on the HI and LO pins on
the IR21844 drivers, on a good board.

i have looked at them with my scope and there is a slight difference between
them,BUT i dont know what i'm looking at!.

also is the power dump board needed with this low voltage ?,because i
don't know why the output blew in first place.
thanks everyone,
mick.

[kreutz]

Hello everyone,
just got my board up and running ,after blowing the output.
Before i test with motor power 38v,would it be possible for someone to
post the waveforms that should be present on the HI and LO pins on
the IR21844 drivers, on a good board.

i have looked at them with my scope and there is a slight difference between
them,BUT i dont know what i'm looking at!.

also is the power dump board needed with this low voltage ?,because i
don't know why the output blew in first place.
thanks everyone,
mick.

You should not measure the waveform on those pins, they are the gate drive outputs, have different reference potential, and it could be as high as the motor power supply voltage + 15V for the HO pins. Look at the waveforms I posted on the original UHU thread while troubleshooting the overheating snubber issue.

If you want to see the driver waveform look at U7 pin 1 and U8 pin 1 respectively, they should be measured with reference to P3 (GND test point), they will be 23.5 khz pulses U8 pin 1 inverted regarding U7 pin 1 waveform.

[mick22]

Hello from a very happy old man,
Thanks to the guidence and advice from this
forum i've just finished a totally successful test on my first hp-uhu
board.
thanks everybody.
mick.

[contactirfu]

power dump circuit I feel is not needed for such low voltages . I think.
this time chk if the tantalums are rated for 35v, the 25v tantalums generated so much heat when burnt that they burned a hold in the UHU pcb.

[mick22]

power dump circuit I feel is not needed for such low voltages . I think.
this time chk if the tantalums are rated for 35v, the 25v tantalums generated so much heat when burnt that they burned a hold in the UHU pcb.

Thanks IRFAN,
i did have that problem,but escaped without damage to the
board,the caps just exploded and left a dirty mess.
rgds mick.

[kreutz]

First tests after successful assembly

Check all the connections, measure resistance across 15V terminals, Motor power supply terminals and motor terminals, no short circuit should be present.

Connect the encoder cable (with the pins 8 and 2 jumpered on the encoder side), RS232 cable to PC, USB cable to PC, and 15 Volt power supply. Connect the motor terminals to the right connector, but don't power on the motor power supply for this test. Do not insert the UHU chip on its socket yet.

Turn on the 15 V power supply and check the 5 volts between the 15V power supply GND terminal and pin 10 of the UHU chip socket. If OK, turn off the 15 V power supply and wait about 10 seconds for the voltage to drop to zero, then insert the UHu chip on the socket

Start the UHU communication terminal software on the PC and turn on the 15V power supply. You should have the UHU information and menu screens on the terminal screen. power ON and Firmware Ready LEDs should be ON.

Program the PID and H parameters, maximum error set to 2000

Turn the motor shaft by hand several turns, the Tracking Error LED should turn ON.

Reset the UHU chip in order to reset the error state.

Turn the motor shaft again in the opposite direction, it should be exactly the same, you have tested the encoder circuit as well as the UHU chip interface. Turn off the 15V power supply.

Connect the Step and Direction pins to the BOB, connect the BOB to the PC, start Mach3.

Connect a 24 to 36 V power supply cables (12 V batteries in series will work) to the motor voltage terminal observing the right polarity (DON'T POWER IT UP YET!!). Turn on the 15v power supply, turn on the motor power supply after a few seconds. Nothing should burn, heat-up or smoke.

Turn the motor shaft by hand, the shaft should try to turn back to the original position and should exert some resistance. If it continues to turn in the same direction as the manual push and the tracking Error LED lights up, shut down the motor power supply first, then turn off the 15V power supply after a few seconds. Reverse the cable connection on the motor terminals. Repeat the test. Nothing should be hot, or smoke. Command some movements by means of the terminal software, beware, the step size should be less than the 2000 figure you setted up for the encoder error count parameter.

If everything went OK, you are ready to begin some serious testing at the required motor voltage.

The USB cable should be connected during the tests and during the PID tuning, its function is to provide 5 volts to the isolated PC serial interface. Without that connection you won't have serial communication with the PC.

15V SHOULD BE PRESENT ON THE BOARD EITHER BEFORE OR SIMULTANEOUSLY WITH APPLICATION OF THE MOTOR POWER VOLTAGE, OTHERWISE THE BOARD WILL BE DAMAGED.

[contactirfu]

HI Mick,

We should thank you and many others for taking up and trusting this relatively new design. Do elaborate on the tests you have done and the parameters you have set.

RGDS
IRfan