Divided by 4 Counter for 2000 pulse encoder

[chrugel]

That is the problem, you are having cross-conduction problems, that is why your UHU chip is resetting. That is also the reason of the HP_UHU modification.

If you dont need the high current capabilities of the HP UHU design ahmedrehan you could use the IRF640. This devis has seriously low gate capacitance and should give you the possibility of up to 160 V and maximum 3-5 amps without cross conduction.

regards
chris

[kodalo]

Hi Ahmed,

Here's a screenshot of the UHU terminal software. I added some text to it.... The motor is an Indramat PMDC servo rated at 19A continous, 150A peak. Drive is HP-UHU with current limit set to ~20A. Encoder is 625lines (2500 counts/rev). I wish there was some kind of scale in the software so you could see just how big the error actually is.....oh well....


The motor is still on the bench so it's not driving anything. I suspect that actually driving a load will dampen the small ringings a bit but will most certanly require retuning.

I had Mach3 loop thru a simple test like this:
G0 X25
G4 P1.5
G0 X0

And here's a screenshot of the motor tuning dialog in Mach3:

You can see that I have the steps/unit set to 2500 which is the number of steps in one revolution and the speed is set to 1800rpm. It accelerates to 1800 in roughly 0.25 seconds.

When running with the UHU-terminal active (ie the Analyzer is turned on) I get some O-counts at this speed but not if I turn off the analyzer.

Hope this helps.

/Henrik.

Hi,
I have the old layout (20/10/2005) and problem with position error. I am using encoder with 500 lines. There is no O-count, but motor always go left. More precisely, if I have started from 0 and G01 X100, G01 X0, (several times)…. G01 X0 after some period it finished at X -2 or similar, not at 0. Analyze shows that left point (X100) has smooth sinusoid (only few oscillations), but changing direction at 0 has more and bigger amplitudes.

It looks like that:

 
                        0 --------- 100
                        --------- 
                      --------- 
                     --------- 
                    ---------

I have tried various paremeters, but without success.
Motor is "pancake" type, and table with specification is damaged, but I think is has 3000 rpm and 90V. I have tried various voltage, but only 16V and slow rev gave acceptable result.
A also have tried with other motors with known specification (24V) and try with voltage up to 30V (115% of nominal) but simptoms are the same.

Why my controller alway run left?

[ahmedrehan]

Hi,
I have the old layout (20/10/2005) and problem with position error. I am using encoder with 500 lines. There is no O-count, but motor always go left. More precisely, if I have started from 0 and G01 X100, G01 X0, (several times)…. G01 X0 after some period it finished at X -2 or similar, not at 0. Analyze shows that left point (X100) has smooth sinusoid (only few oscillations), but changing direction at 0 has more and bigger amplitudes.

It looks like that:

 
                        0 --------- 100
                        --------- 
                      --------- 
                     --------- 
                    ---------

I have tried various paremeters, but without success.
Motor is "pancake" type, and table with specification is damaged, but I think is has 3000 rpm and 90V. I have tried various voltage, but only 16V and slow rev gave acceptable result.
A also have tried with other motors with known specification (24V) and try with voltage up to 30V (115% of nominal) but simptoms are the same.

Why my controller alway run left?

Which breakout board you are using ? try to bypass the optocoupler on breakout board . if you are using laptop then check the result with desktop pc
else your left side circuit of uhu has fault maybe faulty ir2184 or some diode.
check the waveform on oscope at the input / output of bridge circuit.

Ahmed

[kodalo]

Which breakout board you are using ? try to bypass the optocoupler on breakout board.

There is no additional BoB. Only optocoupler on main (UHU PCB CNCECKE from http://www.gertronik.de/cncecke/servo.zip)
What is suggestion for breakboard?

if you are using laptop then check the result with desktop pc

No I am using desktop, but I can try with laptop.

else your left side circuit of uhu has fault maybe faulty ir2184 or some diode.

I have two identical boards and both of them has similar symptoms, so I think components are OK.

check the waveform on oscope at the input / output of bridge circuit.

I will see it.

[kodalo]

Problem solved. Changed optocoupler and now everything works fine.

[ahmedrehan]

Problem solved. Changed optocoupler and now everything works fine.

Thats good news.