Irfan's UHU saga

[contactirfu]

Well after 2 years into getting a UHU to run a cnc router I have learnt a lot of things.

Since I strongly believe that I can make it work against all odds,,,I decided to have my own thread continuing my path towards making the UHU a success on my machine!

here is the latest update!

After the power supply issues were sorted out I connected the 110V supply to the HP UHU, initially the motor locked and when I tried to run Mach and start the motor tuning the motor started vibrating - approximately the shaft was having forward and backward movements of around 40degree to 60 degree contineously, the motor also became very hot!

next the error issue continues as stated earlier - I set the error as per Henrik's suggestion to around 30 and it when I run the circle g code it came to error very soon after less than a turn. again it kept on oscillating.

after a few minutes of oscillating the oscillations stopped suddenly and the motor became free wheel.

Now i decided that I would not test this board and go ahead and build a new one as the older one had gone thru all the odds!

Now my question is

I had removed the 1uF 400v film capacitors across the larger capacitors in the power supply, are those causing the oscillations?

how to suppress the oscillations and the motor getting hot issue!

How exactly to determine if the motor is of a good quality? do you guys think that I should disassemble and check?

does any one of you think that moving to higher voltages might introduce interfering signals on the encoder line (my encoder cable is shielded and the shielding is grounded on the machine side to the mains ground.

one more thing is that many of my friends here state that the mosfets are very delicate, if so can any one guide me how to handle them exactly.

well thats it for now

Thanks for all the help folks!

Regards
IRfan

[contactirfu]

HI folks was finally happy today the machine moved very well!

the parameters set on the UHU were
P - 1000
I - 21
D - 255
T - 150
M - 0
H - 7000

C was default 10000 and I could not change it ?

problems

1. was able to set Error to 2000 and not below? this is very saddning, at this time the voltage at the drive was 105V, I did not measure the current, when I increased the current setting on the UHU the value improved to 1950, but still the UHU would fault when the g0 cycles were ending, I really dont know if this is the problem with the motor if it is really heavy.

2.G0 cycles in mach gave very jerky motions this is evident in the video below I initially thought that tthis would be mechanical problem but it persisted even after the belt was removed ie., the motor jerked in between!

"http://www.youtube.com/watch?v=MlTBGdx7zHc"]YouTube - uhu cnc

I did not note down what IPM it was.

hope some one can help me here now.

RGDS
Irfan

[contactirfu]

[H.O]

Hi Irfan,
First, the jerking. Looking at the video it seems like if the step-pulses from the computer is suddenly interrupted. This indicates that the computer running Mach3 has one or more processes running in the background that interferes with Mach3's timing. Energy-saving apps, multimedia-apps (Quicktime especially) and on board graphics drivers are all known to cause to this.

Try running msconfig.exe and turn off everything that is in the Startup-tab, then reboot and run drivertest.exe located in the mach3 folder, when it runs it should look something like the screenshot attatched to this message. The less "noice" there is on the "trace" the better - mine is quite good.

I'm pretty sure the jerking you're experiecing is due to the computer.

Now, the Error, you need to adjust the acceleration setting in Mach3 to match what the machine actually can acomplish. If you have the accel setting maxed out it may try to accelerate/deccelerate the machine faster than what it can keep up with. You really shouldn't need to set the Error-setting above 100.

I'm also a bit concerned about the C-setting, are you sure it says 10000? The manual says that default is 63 and allowd values is between 30 and 200.

Hang in there Irfan!

/Henrik.

[contactirfu]

Hi Henrik,

was at the inlaws today, will try the settings tomorrow or Tuesday, anywayz I am trying to change the computer ,

the one running Mach is a celeron 500MHz 256mb ram vintage and the new one is a celeron 1.7GHz 256mb ram.

hope it will do better on the new computer.

I will try setting a lower acceleration values in mach.

well its true I cannot set the C values? how they affect the performance I dont know!

well I am going tomorrow to get extra parts for 3 more HP UHU boards tomorrow.

cya later all!

RGDS
Irfan

[H.O]

Hi Irfan,
Although I have heard about people running Mach3 on a 500MHz it is way below the minimum requirements of 1Ghz - I'm actually surprised it runs at all....

The C-value is the recalculation interval expressed in tens of microseconds, that means how often the UHU-processor runs the PID-loop. A value of 10000means that the PID-loop is run at around 10Hz which really shouldn't work at all. The default value is 63 which equals to around 1.5kHz.

I have NO idea why your says 10000 or why you can't change it. Is there any chance you might have change the C-setting by accident? Can you try changing to UHU-processor to another one?

[contactirfu]

Hi Henrik,

had been to get the parts for the UHU, well it does work well in the 500MHzm i will convert that to just a UHU parameter setting PC from now on.

I will try changing the processor tomorrow and update you.

RGDS
IRfan

[kreutz]

Hi Henrik,

had been to get the parts for the UHU, well it does work well in the 500MHzm i will convert that to just a UHU parameter setting PC from now on.

I will try changing the processor tomorrow and update you.

RGDS
IRfan

Thanks for the updates!,

Kreutz.

[H.O]

Hi Irfan,
Any progress (or setbacks) on the issue?

/Henrik.

[contactirfu]

HI Henrik,

I have been trying to get the E stop online and working toward that side. wanted to be safer than sorry! but its taking more time than what I estimated and I am also getting th e proximities set up for limits and home, meanwhile I had to build two more HP UHU's as currently I have only one working.

Last week was quite busy at office, with late nights and long hours. so work on the router got delayed further.

I fixed up the Y- axis motor yesterday and put the new timing belt in. Just completing what I can - when I can. The software tuning parts takes most of the time so kept it for this weekend.

will update you once I have more data to share with every one, and yes I made the heatsink clamps with 3mm thk hylam pasted using super glue with nuts in between.

one more thing .... henrik you were right on the computer end, the 500MHz celeron does give problems with the curve, the new computer dosent!

RGDS
Irfan

[H.O]

one more thing .... henrik you were right on the computer end, the 500MHz celeron does give problems with the curve, the new computer dosent!

That's what I wanted to hear... You are a hard working man, Irfan - keep it up but don't forget to sit back and enjoy once in a while too!

/Henrik.

[contactirfu]

Hi all,

progress on new UHU boards.

got 3 assembled ....