After setting up the G540 yesterday I was playing with the motor tuning......
Here is the setup as it sits.
Minitech Minimill2 1/2-10 tpi precision acme lead screws, xylotex 269 OZ steppers (2.8A) G540 driver and a 24V power supply.

I had the power supply from my first Xylotex kit that took a swan dive on me a year ago. Also for the resistors, I needed 2.8K but the local rat shack only had 2.2K So I am severely under powered by the limit resistors and the low voltage PSU.

Here is a short video I took of it running a test toolpath.
YouTube - Minitech minimill 2 gecko G540 test run

SO what do you think? Can you notice a difference now with it being underpowered or is it just the same? Im inquiring because it has been on my list of things to pick up. Thanks

i notice it in torque as with a little bit of pressure, I can stall the motors. But I am only machining wax. With a 48V PSU and the right resistors, I cant imagine what this sucker will do. As it is, I can go to 45,000 kernel speed and top out the motors in motor tuning. which is just under 3450 mm per minute and it will Rapid all day long. The video was run at 2000 MM per minute. My xylotex/maxnc combo will run reliable at 700 mm per min. But that is apples to oranges

while the jogging looks cool, it all boils down to if the part comes out right, and I am saddened to say that I will re returning the g540. Man I had such high hopes!

So your saying your xylotex is better than the 540?

I am going to say that the xylotex that I have is 1000% better then the g540 that I have. Why? because while the g540 tosses the machine around fast and smooth. When it comes down to making a part. I cannot get the g540 to cut a simple design in wax. it comes out ugly wrong!!!!!!! If it cannot faithfully produce a model for me, then its useless. I put the xylotex kit from the maxnc on the minitech mill and it cuts fine.

Thats really odd, I have yet to set my 540 on the mill. I'm sure some of you remember about 4 months ago my whole Xylotex problems???? I was skipping steps, couldn't even cut a piece at 1 IPM. it was horrible, went back to my "No name" drivers and cut like butter.


-Jason

because while the g540 tosses the machine around fast and smooth. When it comes down to making a part. I cannot get the g540 to cut a simple design in wax.

Weird, think it can't handle complex 3D moves?

im still testing......

There was a Recall on my Gen 2, new one came in the mail today. But it doesn't constitute to your problem.


-Jason

for those of you who haven't seen my thread in the gecko section, My stubbornness paid off, I was finally able to get a descent wax cut with the g540. I figured I would spend one more day on it before sending it back.

Come to find out, that when I enabled the sherline 1/2 pulsing mode in mach 3 all my problems went away and I was able to cut my models just fine.
Speed, I dont know if this will effect you and your EMC2 setup but keep it in mind buddy.

I was even able to cut a model at 2500 mm`s per minute and while the wax had a few minor flaws due to the speed. I was greatly impressed.

After setting up the G540 yesterday I was playing with the motor tuning......
Here is the setup as it sits.
Minitech Minimill2 1/2-10 tpi precision acme lead screws, xylotex 269 OZ steppers (2.8A) G540 driver and a 24V power supply.

I had the power supply from my first Xylotex kit that took a swan dive on me a year ago. Also for the resistors, I needed 2.8K but the local rat shack only had 2.2K So I am severely under powered by the limit resistors and the low voltage PSU.

Here is a short video I took of it running a test toolpath.
YouTube - Minitech minimill 2 gecko G540 test run (http://www.youtube.com/watch?v=E1YCCgS6EAg)

Here are the resistors you need you get 100 of them for $1.00
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=170040546439

So am I correct in reading that your machine error was in the software pulse setup not anything to do with the drives?

I've seen a lot of hype about the 540's but haven't really followed them closely. I needed a bit larger than the Xyoltex could provide (and I wanted headroom) so I went with 203Vs but understood they were essentially the same backbone just stripped down a tad.

It is correct in saying (To an extent) that my issue was software setup. With help from friends, and the forum and process of elimination I stumbled upon the fix. Dont ask me why the machine works when I turn on sherline 1/2 pulsing mode. I do not understand it, but the machine works. So with that being that............ its clean up time and production time again, I have to get caught up.

What does the 1/2 pulse mode do?

my standard answer to that question has been "it makes my stuff work!!!"

What I believe it does, it sets a different us value, just like in EMC2, mach seems to have this for people with different drivers, keling drivers will differ from Gecko drivers and so will the timing "us", by you changing this, it must of set it to the correct value.

Hope that makes sense.

-Jason

What does the 1/2 pulse mode do?

Sets the pulse width to 40us in Mach3.

Then it was a software/setup fault, and not a driver fault. So the new G540 IS actually working as it should...?

i am strill trying to find out "WHY" i hae to be in the sherline mode for it to work right, from my other thread, I have gathered that this is NOT the norm. Nothing I do is ever easy......

Isn't there anywhere in Mach where you can set the correct pulse width? If there is, then try setting it to 40us, and turn of the 1/2 step mode.

If the 1/2 step mode does change the pulse width, then thats your problem.

From Marris at gecko, he says that the pulse width should be 2. That is a long stretch from 40. also I have found you can manually set it up to 15 in the motor tuning. but setting it that high may crash the computer.......

You might want to try faster kernel speeds. I believe that I read that if the PC can handle the faster kernel speed, you may get a more consistent pulse stream.

i have tried all kernel speeds, I believe that the weak point in the system is the power supply. When I get the means to upgrade it I will and try the tests again. But for the time being I am going to try and get the machine to pay for the new drive soon :)

I think I know what is going on. The computer you are using to control the gecko 540 is probably newer and as a result your parallel port can't source enough current to drive the optos on the G540 with two microseconds. On modern computer parallel ports only 40 us of pulse width is long enough to fire optos reliably with the low current modern parallel ports have. Without the Sherline 1/2 stepping mode Mach3 seems limited to 15us pulses at maximum.

Just add a buffer chip between the parallel port and the G540, then run whatever pulse width you want and the buffer chip will drive the optos in the G540 with plenty of current.