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cmcgrath5035
ModeratorCool, good luck with the build!
ModeratorI assume you have read this a few times:
And this is somewhat a guess.
I search the wiki, cannot find a definition of mposx or mposz, but guess they are Machine position x and z. (Machine position relative to 0,0,0 after homing cycle)
I’ll also assume that your Gcode is not running in the G53 coordinate system, rather it is running in G54 or perhaps another.
Perhaps the “offsets” you are seeing are the offsets of G54 relative to the Machine (Homed, G53) ?.Perhaps by defining a different SR string, requesting posx/posy/posz rather than mposx, etc., you will see what you are looking for?
There is also a possibility of a bug in the reported position reporting, I know one has been identified in $fb=440.14, cannot tell if it is yours.
You need to know that:
A. tgFX is very much out of date and no longer supported. Don’t design around it and wean yourself off to something else. I doubt it is contributing to this issue.
B. $fb=435.10 is very old, if this is a bug, it will be fixed in $fb > 440.14
You really should update to 440.14, many fixes. High likelihood tgFX will misbehave with 440.14; that will not be fixed.ModeratorAhh, good catch. Thanks for heads up.
EnjoyModeratorI wandered a bit on their website.
Looks like a ball-screw machine with Nema 23 motors, I am going to assume 4 motors but did not actually see the Y axis motors
Key info you need to provide for tinyG setup :
Ball Screw Travel per revolution – for Setting X,Y and Z $_tr
Stepper steps per revolution – 200 or 400? 200 Typical ($_sa = 360/200 = 1.8deg)
TinyG drivers only support 2,4 or 8 microsteps.Assuming there are steppers on each Y rail, do they counter rotate? That would likely provide the best performance, implies Y motors one each normal and reverse polarity.
Start here:
Maybe start with just the Single X motor to get a feel for how parameters interact with a simple axis
ModeratorIt would have to be a substantial diode and perhaps a fuse of some sort – Vmot can be some substantial current Power Supply.
Even with that, Silicon diode might not be adequate.I have had same thought; it is a challenge for sure.
ModeratorThere is no one location for all LED indicators; a good rainy day project I suppose.
You can start here:
Then wander thru other wiki items that will reveal what the LEDs are telling you.
Enjoy
ModeratorThanks for posting the reference.
Thinking about it for a bit more, I was distracted by the comment that it worked with the other 3 controllers.As a general statement, putting two “buck regulated” [transformerless] supplies in series or in parallel is probably not a great idea, there will always be a reference, through the input diode bridge, between the outputs and input AC Line and Neutral.
ModeratorI am not sure what you are asking.
$p1pof = 0.1 means that in the off state, the PWM phase (pulse width) is 10%.
This may, or may not, be the correct value for your PWM controller IF you have one.
$p1pof=0.1 WILL result in the LED being on all the time (actually 10% ON but hard to tell defference between 10% and 100%)If you are using a PWM spindle, you have to set up for your particular controller, etc. The reference I provide is for one particular (and common) interface.
If you are not using PWM, but want the LED to turn off when spindel not running, set $p1pof to 0.0
ModeratorOn this page of the schematic
P1 and P2 are the pots for, I think, motors 1 and 2.
I think the wipers of the pots are what you are looking for as they connect to the driver Vref, pin 8.
There is no layout diagram that I am aware of, likely finding a via, etc would just be luck.
If you are read good at soldering, you could add small wires for clip leads, I suppose.ModeratorYou are running the most current FW, good.
LED is on because , likely, $p1pof=0.1, the default value.
For deeper discussion, see:
ModeratorOff the top, looks odd.
Tells us a bit about
What firmware build are you running? $fb=440.14 is most up to date
What OS do you use to control (Mac, Win, Linux, ) ?
What program to deliver Gcode?(CoolTerm,. Chilipeppr, ) ?When you say “JSON text file that is outputed by the controller.”, you mean the streaming status reports that come back while Gcode is running?
We will likely want to see your full parameter set sooner or later
ModeratorI am still curious as to the origin of a 12V offset between tinyG GND and PC chassis.
The only logical cause I can come up with is that unintentionally the center tap (middle) of your series connected power supplies is referenced to earth (e.g. green wire to the connection in a three wire power cord), but that is not what you decribe.Does the offset go away if you disconnect from your PWM controller?
If so, can you describe what PWM controller and Spindle you are using?
Do you have a separate PwrSup for the Spindle? What V?ModeratorOK, after some digging I realized that you probably did have default settings, $xtr=1.25mm is the key for me, that is a default value. So your would not expect to see changes after the $defa=1. I had you do the defa=1 since it reloads some non-user settable (not visible with $ or $$)internals as well that might have been contributing, based on the experience of others.
Lowering the feed rates was a good experiment, but frankly the motors require very little current to spin when unloaded.
The fact that tinyG fw was misbehaving (disconnecting from PC) is also a good indicator that PSU was drooping, causing logic level voltages to excessively droop on-board, likely causing tinyG to reset. It seems a common failure mode in the supplies is for the current limiting detector to fail, resulting in full output at low amps output but output voltage droops (fails) under load. Since steppers demand current in very short pulses, this can be difficult to diagnose with just a voltmeter.
Since you are NEMA23s, go with the 350W supply. 14A is a bit of overkill, but 6A (the 135W) would be marginal.
If you want to play with your existing supply and it has an “output current adjustment POT”, you could (off line) crank that pot back and forth a couple times, then leave it set to max. A common failure mode is a ‘dirty pot’, sometimes this will yield short term improvement, but frequently the improvement does not last long.
ModeratorI frequently encounter high impedance chassis to chassis voltage offsets due to (??) leakage to “gnd” in switching regulators and supplies, a good example would be a DVD player and an LCD TV, producing a mini-arc when connecting one chassis to the other via a coax, hdmi or USB. Sounds to me like you encountered a low impedance version.
I don’t have any experience with the other three boards you are using.
Do you have the PWM spindle driver output somehow connected to (referenced to) “gnd”?
Most of the hobbyist cnc systems lack the concept of ground bus managementIf of use, you will find the tinyG schematics here
ModeratorAs you describe it, I don’t see how this can be a tinyG issue but I don’t have one in my hand either.
I believe that the tinyG USB shield is connected to the Gnd lug of the Vmotor input. I’ll say I assume your other three boards were same.
If I am reading you correctly, you are measuring 12V between the neg side of your series connected 24V (=12V+12V) supply and the chassis of your computer, ?
If true, why?
Seems one of your two 12V supplies is therefore referenced to whatever the computer chassis is connected to.I am just curious, do you a a PWM spindle supply connected as well?
I find it very difficult to figure out what ground is there.-
This reply was modified 9 years, 2 months ago by
cmcgrath5035.
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This reply was modified 9 years, 2 months ago by
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