Thread: dynapath axis lag

HI I'm having trouble with my tree 310 running from one line to another .The in position asterick is not coming on all the time for all of the axis . some members think the servos need tuned. the axis lag shows .0027 on all of the axis when there is nothing moving. If you jog a axis with the handwheel it may go up to .100 or higher. How is this adjusted thanks again for all the help

Gary

I am lucky to have a relative who happens to be a generous & very highly trained CNC technician. He adjusted the axis lag on my Dynapath 20 control. It was explained to me in a 'horse & carriage' analogy, but think of the connection between them as a rubber-band: The control & servo is the horse; the carriage is the table. The delay in postition between where the control is & where the table following it *actually* is should be zero, ideally.

Here's what he did:

1) Go to Mode select...5....(Setup).....enter
choose TM4 ....Servo Adj....enter
Now go back to Mode...0 ....enter

On the display (ideally) you should now see this:

Axis Lag
X +000.0000
Y +000.0000
Z +000.0000

(but your display probably will *not* show zeros....that's why I'm writing this.....that's what you're trying to do)

2) Open the big control box and find the servo-amplifier boards....they might even be labeled. You MUST find the X & Y & Z. Hint: there are 6 tiny adjuster-pots on the edge of each board. The voltages here are quite low...so you won't get a shock BUT cover the open terminals of the transformers if you're clumsy &/or nervous. I dropped a screwdiver on these once...a near miss....almost shorted-out the transformer)
Find the pot marked 'Bal' for balance.

3) While a friend, associate, wife, or other trustworthy person observes the display, particularly the Axis Lag numbers, you are down on your knees with your nose close to the servo-amp boards: Tweak the 'Bal' pot on, say, the X-axis. Ask what change in the display...a higher number? Then tweak the other direction. Have your friend report any changes. When the value gets to zero....Stop. This means there is no lag now on this axis.

Now adjust the Y-axis the same way as X. Then do the Z-axis.

That's it. Done. I was told that this value may drift with seasonal shifts in temperature. Check every so often.

Now *REMEMBER TO SET THE CONTROL BACK TO 'TM1'.... Feedrate over-ride.

Hope this helps.

Gary,

The procedure Dogstar explained is exactly what I did to the Delta 50 controller with the exception of my servo amp board having an offset pot which I used to set zero.
I also used signal input pot to adjust amount of lag to get as low as possible. To minumize the lag with signal pot the adjustment must be made with axis moving.

Hope this doesn't confuse the issue.

Doug

very valuable posts gentlement. thanks vey much

Thanks for the info I adjusted thw balance pots but I'm not sure how far you should have to turn them. the lag was about .0027 on each axis turning the screw doesn't seem to make much difference I turned the z azis about 4 turns it did bring the lag down to .0018 but it makes more noise while jogging I may have to hire someone to fix this. thanks again

There`s a bit more to servo tuning than just adjusting the balance pots.I would also be very wary of the statement "the voltages here are quite low,so you won`t get a shock"
Most axis drives I come across are carrying voltages between 160 and 660v which can do more than just give you a shock.

I adjusted the signal pot and the lag went to zero but now it e-stops with a error for the axis in rapid other wise it will run a program. which do I need to tweak the balance or the signal thanks

Gary

I thought there might be more of a problem....As you'll notice there are six trim-pots there and of course they all are there to do something. But I cannot tell you more.... this is the limit of my knowledge about these things. You may have to get a technician....and an oscilloscope.

I haven't pretended to know everything, or even a lot...only what I was shown about trimming the axis lag. I've sent a couple of PDFs to your email address about servos tuning, info that I've found. Good luck. Let us know how it all works out.

i think i have instructions on tuning with an oscilliscope but it is over my head. I'll see if i can find them for you.

If the E-stop only happens in radid it sounds as if you have an axis binding. Your fault message should tell which on had the error.
Also getting the lag too low will cause the increase in noise.

There is more to the complete tuning procedure than a simple adjustment of the bal pot.

The complete instructions are in the installation manual, they may be available from Servo Dynamics also (if you have Servo amps).


Why does this seem to be such a problem with Dynapath machines? Is it just a coincidence we get this question so often about these machines?

I too am having problems tuning a Y-axis servo on a Dynapth 10 control. The machine is a Lagun mill. Anyone have tuning procedures??

Move the axis in each direction and let it stop. Then adjust the balance so that you get the same number in both directions. If you just adjust after stopping in one direction the lag in the other direction will be much greater. It will usually total about the same.

On my x-axis, if I set it to zero in one direction, it read .006 the other. So I adjusted it to .003 in each direction and it worked best.

I think if it is off .0045 in either direction it will have problems. My other axis's were better -about .0015 in each direction. The x-axis was the one that had the same * pause problem you are having.

Our Tree 1050 started doing the same thing on the X-axis about a month ago. We did some trouble shooting and ultimately changed out the servo amp due to a shorted power cable to the X-servo motor (replaced power cables to X & Y motors as well because housing was cracking off of cables). Problem solved, until today when the same problem started happening again on the X-axis. Has anybody in fact solved this issue? Any help is much appreciated.
Josh Taylor