Messages

21

Mach SDK plugin questions and answers. / Re: MPG over USB?

« on: June 12, 2015, 11:44:02 PM »

IN MPG mode it should operate as  step mode . Each click moves a determined amount as defined in the MPG setup. You SET the resolution of the steps.
.0001, .0010, .0100, .1000, or 1.000.

Just a thought(;-) TP

That is how the pendant behaves, but I don't believe it is consistent with the normal meaning of an MPG controller. As you said, each click moves on step based on the current step size. If you turn the wheel faster than the step can be performed, it caches the steps and continues moving even after the wheel has stopped. My understanding of "true" MPG mode is that the machine will move as you turn the wheel. Turn fast, the machine moves fast. Turn slowly, the machines moves slowly. Stop turning the wheel, the machine stops. No caching steps, no dependance on the current step size. And that is why I suspect it can't be implemented in a USB card. Mach3 has to send raw steps (as in stepper motor steps), and I wonder if this is possible via USB.

22

Mach SDK plugin questions and answers. / MPG over USB?

« on: June 12, 2015, 09:48:54 AM »

Sorry for cross-posting, but it seems this might be a better forum to post this question:

I have Mach3 connected via USB to a Xulifeng (aka Leafboy) controller card. I just bought an XHC HB04 pendant with an MPG. All the functions work except for the MPG. The wheel itself works in continuous and step mode. In MPG mode it operates as if it's in step mode. After much head-scratching is occurs to me that the MPG might be incompatible with this setup. Unlike parallel cards where Mach3 is sending steps, the USB interface is sending some higher level commands. It occurs to me that the USB interface might not support MPG, either because Mach3 doesn't offer low enough level commands, or because the vendor didn't implement the MPG level commands. Anyone know which of these many possibilities is correct?

Thanks

23

General Mach Discussion / USB controller card and MPG

« on: June 10, 2015, 09:32:11 PM »

I have Mach3 connected via USB to a Xulifeng (aka Leafboy) controller card. I just bought an XHC HB04 pendant with an MPG. All the functions work except for the MPG. The wheel itself works in continuous and step mode. In MPG mode it operates as if it's in step mode. After much head-scratching is occurs to me that the MPG might be incompatible with this setup. Unlike parallel cards where Mach3 is sending steps, the USB interface is sending some higher level commands. It occurs to me that the USB interface might not support MPG, either because Mach3 doesn't offer low enough level commands, or because the vendor didn't implement the MPG level commands. Anyone know which of these many possibilities is correct?

Thanks

24

General Mach Discussion / Re: what is Mach3 sending to the controller over the USB connection?

« on: April 10, 2015, 12:01:05 PM »

As Gerry noted, it's not sending g-code or step pulses. What it is sending is a bit of a mystery to me. The USB probe shows a pretty constant interaction - packets going back and forth every couple of  milliseconds. Not enough for steps, way too much to be any sort of high level trajectory control.

I've looked at the SDK but unfortunately it contains no documentation other than commented code (or at least none that I could find.) Kind of a hard way to get an overview of how the interface is designed.

I haven't been able to force the error to occur while the USB snoop was in operation, so I don't know where it's occurring. The nature of the problem appears to be that a move is commanded but at some point the movement stops but Mach 3 thinks it's continuing to the end of the commanded motion, then motion starts up again with the next g-code, but the machine has lost position, possibly by thousands of counts (many inches). This failure could be anywhere - the PCs USB stack, the controller, ... hard to tell, esp since it's random.

I suppose something to try is the read-ahead latency in the plug-in, though without repeatability knowing if it fixed the error will be hard to determine.

25

General Mach Discussion / what is Mach3 sending to the controller over the USB connection?

« on: March 30, 2015, 11:15:43 PM »

Is Mach3 sending step pulses, some higher level trajectory information, or perhaps even g-codes? Perhaps different USB controllers accept different level inputs. Is there an easier way than snooping on the USB port to tell what's going back and forth?
For what it's worth, I'm using a Xulifeng Mach3 USB Board, sometimes labeled as the AKZ250. The USB interface is handled by an ATMEL mcu, it looks like the stepper pulse formation in going on in an Altera CPLD.

26

General Mach Discussion / Re: program skipping commands (not steps)

« on: March 28, 2015, 12:26:04 PM »

Code is 492 lines, containing no comments.
Error is occurring around line 7

Note that the error is NOT repeatable

27

General Mach Discussion / Re: program skipping commands (not steps)

« on: March 28, 2015, 11:25:46 AM »

It's an AKZ250 supplied by JCut on a 6090A router.

28

General Mach Discussion / Re: program skipping commands (not steps)

« on: March 28, 2015, 10:56:27 AM »

ger21 wrote:

It's most likely a case of your steppers losing steps which is causing the lost position. Try reducing your acceleration and velocity in motor tuning by about 20%.

It seems a rather remarkable coincident that both the x and y axes would skip a number of steps exactly equal to those commanded in the G1 command.
In addition, the program consists of the same sequence of moves being made repeatedly, just shifted in Y, but never again are steps missed.

29

General Mach Discussion / program skipping commands (not steps)

« on: March 27, 2015, 11:07:22 PM »

I was running a fairly simple program today and the machine appears to have skipped over two G1 commands. The reason I say skipped commands instead of skipped steps is that when I checked the machine location after the program ran, it was off by exactly .5" in X. The program was taking .25" steps in X, so this would be consistent with skipping over two G1 commands. This has happened once or twice before in the past couple of months. It is not repeatable, and it is not an error in the program, since I can run the program again and get a correct cut (as well as run it in OpenSCAM and get a correct visualization).

Any thoughts on how to prevent this in the future, or at least confirm this is the problem?

I'm running Mach3 on a Core 2 Duo Windows 7 machine, talking to the router via a USB controller board.

30

General Mach Discussion / Re: Spindle requires two inputs for control

« on: October 16, 2014, 12:14:47 PM »

Thanks for this additional info. Clearly I'll need to learn about macros and the capabilities they provide. At the moment I'm trying to get my CNC router running. It came with no instructions other than eight screen-shots of Mach3 setup screens, and three of those were wrong. I'm new to Mach3, so this information is tremendously useful.