Oscilloscope settings for G320 servo tuning + trouble

[giorgiocnc]

Hi everyone!

I'm currently setting up my G320's and have read in the installation notes, that you need and Oscilloscope for proper tuning. So I borrowed one. At the encoder testing section the notes say: place the probe on the test point and the ground clip to the blue capacitor ground lead. This is clear. But, at the Gain and Dump section it says: use channel 1 on the test point and channel 2 on the DIR input. Set trigger to normal, trig source to Ch. 2. trig edge to +. Where do I put Ch .2 ground? To the same place, blue capacitor gound lead? Do the same setting (2 volts/cm vertical, 1 ms/cm horizontal) apply to this measurement also? Has anyone done this before?

Any help would be greatly appreciated.

Giorgio

[giorgiocnc]

I've just took apart my Gecko, and again, the manual is quite confusing. The schematic picture on the 2nd page is wrong, the test point ground should be the gnd leg of the big blue capacitor, right? I've measured the voltage and it is 5.36 V, which doesn't seem ok to me. Also the Fault light is not lit for 3 sec when turning on power, but only for about 1 second. When checking the STEP/DIR wires, again its lit only for 1 sec. If I use external power supply for the encoder, since it should be around 130mA according to the documentation, the motors never stop slowly rotating, even when STEP/DIR isn't connected at all. If I use the internal power supply however, the motor rotates about 45 degrees, Fault light goes up, after 1 sec it goes down, motor rotates again, fault light up, ... over and over again. Did it with two motors of the same kind, Sanyo Denki Super-R720 012E-18. I have tried 40V DC power supply, 50 V and 60 V, the motor is rated at 75 V. There are no shorts in the wiring, there is a heatsink on the Gecko, but it doesn't even get warm, fuses are installed, I draw +5VDC from the computer. Does anyone have any ideas, please?

Br, Giorgio

[Runner4404spd]

i'll be tuning my servos tonight and will get back with you later on what i discover. if you come up with anything please post it so i can follow what you did. i'm running 24V motors and getting the 5V from another supply. the computer generated 5V may not have enough amps to run the geckos and the enconders.

[giorgiocnc]

This forum wasn't much of a help (actually it wasn't help at all ), but I got a very usefull reply on the Geckodrive Yahoo group from Les. His answers:

>Where do I put Ch .2 ground? To the same place, blue
>capacitor gound lead?
>
Either to the same place or leave it disconnected. They are both
connected together inside the scope.

> Do the same setting (2 volts/cm vertical, 1
>ms/cm horizontal) apply to this measurement also? Has anyone done
>this before?
Yes, use the same settings.

>I've just took apart my Gecko, and again, the manual is quite
>confusing. The schematic picture on the 2nd page is wrong, the test
>point ground should be the gnd leg of the big blue capacitor, right?
>I've measured the voltage and it is 5.36 V, which doesn't seem ok to
>me.
>Is the -Ve side of your power supply grounded? If not you may well
measure an odd voltage there.

> Also the Fault light is not lit for 3 sec when turning on power,
>but only for about 1 second. When checking the STEP/DIR wires, again
>its lit only for 1 sec.
Don't worry about it.

> If I use external power supply for the
>encoder, since it should be around 130mA according to the
>documentation, the motors never stop slowly rotating, even when
>STEP/DIR isn't connected at all.
This is a classic symptom of the drive not seeing the encoder pulses.
You have connected your external power supply's ground to the Gecko's
encoder ground haven't you? Also see the above comment about grounding
the drive power supply.

The Geckos are up and running now, I'm still fine tuning them. Br, Giorgio

[DennisCNC]

giorgiocnc :This forum wasn't much of a help (actually it wasn't help at all )


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