Serious CNC Progress

Sorry I haven't posted any updates in awhile. Women. lol.

We've received our CNC4PC board in the mail, it was delayed cause they were out of stock. It will control the spindle, it is controlled by an RJ45 port. (ethernet)

I've been working with Noobie on AirsoftRetreat to develop a new hopup solution. We've made considerable progress on that, I will release more information as we release it to the public. I made some prototypes and sent them to him for testing by USPS.

Troy tested a few of some old ATX powersupplies and used a jumper to quickly test the output of the powersupply. This website tells you how to jump it. Interesting...
http://www.duxcw.com/faq/ps/ps4.htm

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Troy and I fabricated the Stepper Power Supply from the various parts we've gathered and purchased. This consisted of:
-Antek Toroid (36VAC/18VAC/12VAC)
-Bridge Rectifier
-22,000 microFarad Cap
-7Amp Breaker.
-Old Pentium II Case
-Blade connectors
-12 Guage Wire (I think)

Troy was hoping to use a cap diode to condition the DC side of the power supply to cause a voltage drop to 36V. On our first test this resulted in a surprising catastrophic explosion of the diode. It was startling, and certainly opened our eyes a bit. We later realized this was because there was no load. Troy surmised to utilize that method would require a lot of resistors that could sap about 100Watts of power - not feasible. We also pondered Voltage Regulators - but they would require too many to properly work.

Forgive if my memory fails me for some of these stats... From the Transformer we were getting 36VAC, and through the Bridge rectifier we were getting 33VDC??. Through the capacitor we were getting 48VDC? This was too high. We measured the voltage in parallel to the capictor with the multimeter. We didn't completely think it through with the transformer because we thought the 36Volts would be DC not AC. Due to the nature of Vrms and the circuit we yielded the high 48VDC. Fortunately the transformer had a couple other power configurations. At 18VAC you get 24VDC through our circuit. So we undid our quick solders and switched over to blade connectors as Troy originally suggested as they are much easier to use. (Yup you were right Troy lol.)

This went off without a hitch, other than the scary part of discharging the huge cap. (as sparks fly) Something about it just feels wrong to drain the capacitor that way... (arcing it with a pair of insulated pliers.)

With the functioning 24VDC power supply we used that to test the connections on the control board. With the board layout properly verified with the multimeter Troy installed the remaining three driver chips to the PCB. I then pulled out an old Athlon computer I had located. We verified the potentiometer settings were correct with the power supply, control board, and multimeter. With the 2Amp rating for the steppers in unipolar mode that yields ~ 0.28VDC on the potentiometer. This stat was found on the specification that came from hobbycnc documentation. They were each set and the cap was drained. We waited several minutes and then refered to:

- http://www.kelinginc.net/KL23H286-20-08B.pdf
- http://www.cnczone.com/forums/showthread.php?t=61976

These were very helpful, and verified our interpretation of keling's documentation. Troy wrote a translation table between the controlboard and stepper documentation which I will take a picture of later. He wired one stepper up to the board after the capicator was less than 0.1Volts. After that, Troy had to leave. Bryan helped me out from then on. We installed Mach3, checked the pulse generation to be a bit shaky for the machine - it seems a bit slow. Sadly, the 750mhz computer has been tweaked for maximum performance already. I have it down to about 16 processes (this is very low.) We were ranging in the 25K to 15K PPS range.

We spent awhile configuring Mach3 attempting to jog the X-axis (the only stepper we had connected.) We figured out how to disable the E-stop break by switching the activelow signal. While this allowed us to green light the machine (make it ready,) we were unable to move the stepper. After a while, we decided to go buy food. Then we stood up and I noticed I hadn't plugged in the Stepper Power supply. LOL. We booted up again, and attempted to jog - no dice. Tired after a long day we got food and headed home.

I hope to figure out the issue by tommorow. I suspect software configuration is at fault.(and hope this too, I don't want to have to resolder the board.) I am certain patience, and persistence will get us through this hurdle.

The prospect of making an axis work is just too exciting! Pictures to come!!