Campbell Breakout Board

[hybidder]

I have a 5/ 12 volt supply aleady in the machine and I have a computer 5/ 12 power supply I can use as the second supply. Thanks for the headsup Torchead, I had not thought about needing a second power supply for isolation.

[Torchhead]

Originally Posted by hybidder I have a 5/ 12 volt supply aleady in the machine and I have a computer 5/ 12 power supply I can use as the second supply. Thanks for the headsup Torchead, I had not thought about needing a second power supply for isolation.

Computer power supplies typically have a common ground (chassis) and the safety ground of the AC.....That will tie everything together and defeat any optoisolation advantages for ground loop prevention or ground conducted noise issues.

The whole grounding thing gets confusing because no two grounds more than a few inches apart are at the same potential. (ground is not Ground!) The more current there is between the systems and the higher the frequencies the more pronounced the difference. For logic level circuits a volt or two of noise can produce unwanted effects.


Two opto isolated systems must have separate power supplies that do not share the same ground (common). The whole point of the isolation is have the "galvanically" isolated.....no chance for current to flow for any reason.

Since the Campbell card comes with two separate supplies on the card and they are already hooked to the right place all that issue is resolved.

I am not a big fan of triac based (solid state) relays unless you KNOW what the load is going to be. Highly inductive loads can cause triac misfires and jittery operation. That noise can be reflected back into the AC line. They don't work with softstart router controls or DC anything...including logic to VFD's or a plasma torch on signal. Conventional electromechanical relays are more reliable in a world where you never know what will be hooked to them.

Speed controls made for routers use the fact that a universal motor's RPM is proportional to the applied voltage....unfortunately so is the torque. The same is true for DC motors. At a given voltage when you load them the RPM drops. Unless you have some form of torque feedback from the motor maintaining anything close to a constant speed with a simple phase controller is impossible. As you crank down the RPM it's more pronounced. Constant RPM with an AC speed control is fairly straighforward. For a DC motor it's more difficult.

Sometimes the devil is in the details. Just adding components to a board does not always solve the problem....than takes engineering.

Tom Caudle
www.CandCNC.com

[hybidder]

Originally Posted by Shepard I'm using the Campbell breakout board plus not the combo board and there is no onboard spindle control. I know the cnc4pc board has spindle control and if memory serves it has a lot of features for half the price of the combo board. I don't know about the combo board but home/limit is a pain with the breakout board plus. I originally went with the Campbell board because it supplies the 5volts for the geckos. I'm sure everyone's experience is different but I was never able to get ANY customer service after numerous emails to Campbell and they have no phone number. Anyway, I'm planning the cnc conversion of my lathe and will be using the cnc4pc board. They have answered my email questions within 24 hours and they run at my friend's house 8-10 hours a day.

I finally had some spare time to wire up my C11G breakout board to my Gecko 203v drivers. Everything (so far anyway) is working as well as I had hoped. No glitches and my motors are running much smoother than they did with the outdated Centroid boards. I spent an hour or two with a ballpoint pen in my spindle and a piece of paper taped on a scrap aluminum plate drawing shapes as I ran through some of the wizards in Mach3. I finally felt confident enough to put an endmill in and cut a 2.5" circular pocket which turned out to be a 2.321" pocket so I have some step count tuning to do but I'll work on that in the next few days. I only ran the X & Y since I need to do some work on my spindle but hopefully in the next few days I can get it back togther.

Anyway- back on topic, I don't have any exposure with the Cambel board, courtesy of this threads suggestions, but from my early experience with the CNC4PC C11G board, I feel safe to recomend it. It was shipped quick and my emails regarding the sale were answered within a couple of hours. The directions were adequate, but for a novice such as myself, a little more detail would have been nice however I managed to get it all togther without asking for service support.

[dimaker]

i just purches a breakout board from cambel designs. i removed the cheapie board and wired in the new board. i have only the 110 volt and the step/dir/com wires to my gecko 203v 's. when i try to jog the motors will no reverse. it appears my pin assignments are correct. running mach 3. with my meter i am not geting any direction switching on the dir terminal out of the board. help.

[dimaker]

nevermind i got it working

[dimaker]

nevermind my nevermind, i only got thedrives working by changing pin asignments to x dir2, x step 3, y dir 4 x step 5, z dir 6 z step 7. bob cambel said this should not work. none of myhome switches are working with cambels recomended pin asignments. im back to me cheapie board.
i would like to get my cambel board working. nothing works right when i use thier recomended pin asignments. i tried two boards, two computers and same results. any ideas?

[Torchhead]

The proper pins are X Step 2, X Dir 3, Y Step 4 Y Dir 5 etc. You have to use the correct polarity to the Gecko Common (PC Ground) AND the Step signals HAVE to be POS (red X) in the Ports & Pins/Motor Outputs. Probably the reason it's working like you set the pins is that the polarity of the signal is correct (Dir polarity just determines the direction the motor spins. Go back and set the pins correctly and flip the Motor Output STEP active low on each axis to POS (red X).

TOM CAUDLE
www.Candcnc.com

[jetflatline]

"There are no stupid questions, only stupid people."

Can I run the servo/encoder Gecko G320s with the Sound Logic Combo Board (the one with VFD support)? Bob says the Combo Board is a direct upgrade of the Encoder Interface, but the docs for the Combo Board only talk about steppers while the Encoder Board mentions both.

This is my first experience with servo/encoders and I'm thinking that the STEP and DIR is going to work on the Combo Board the way it would on the older Encoder Board. Am I about to get what I deserve for "thinking"?

[Torchhead]

Originally Posted by jetflatline "There are no stupid questions, only stupid people." Can I run the servo/encoder Gecko G320s with the Sound Logic Combo Board (the one with VFD support)? Bob says the Combo Board is a direct upgrade of the Encoder Interface, but the docs for the Combo Board only talk about steppers while the Encoder Board mentions both. This is my first experience with servo/encoders and I'm thinking that the STEP and DIR is going to work on the Combo Board the way it would on the older Encoder Board. Am I about to get what I deserve for "thinking"?

As far as MACH is concerned, there is no difference between a Stepper or Servo setup. All of the encoder feedback on a servo is done at the G320X. The BoB just has to supply the normal Step & Dir logic signals to the drives.

[jetflatline]

sigh.

I went and re-read the G320 manual and now it makes sense. I'm so used to reading position upstream that I was completely oblivious to the fact that the G320 was taking care of reading the encoder for for me.