Messages

1241

General Mach Discussion / Re: Gaining steps...maybe? with Servo Drive

« on: July 26, 2011, 08:39:09 AM »

Tweakie may well be right, but as a shot to nothing I may have an idea why noise could cause extra steps in one direction only AND why it might be worse the slower the feedrate. To check it out, try leaving your axis stationary a while and see if over time, it gently creeps upwards.

Cheers

Ian

1242

General Mach Discussion / Re: Gaining steps...maybe? with Servo Drive

« on: July 26, 2011, 06:52:06 AM »

but why would noise only affect one direction? If it was on the step line then surely it would affect both directions. If it was on the dir line then sure a LOW direction signal is (I think) more susceptible to noise, but it would (theoretically) momentarily reverse the intended direction and therefore look like LOST steps albeit predominantly in one direction.

Sorry - no help I'm sure - just bouncing thinks.

Ian

1243

General Mach Discussion / Re: Motor issues

« on: July 26, 2011, 04:17:45 AM »

Hi Rod, OK if my maths is correct everything checks out pretty good. The only thing that is amiss is that your kernel speed no way needs to be 100KHz. The plain vanilla 25KHz setting is more than twice what you'll ever need from the info you've posted.

Whilst a 64V supply would give the "optimum" torque/speed curve for your motors, as you never go much above 1300 full steps/sec your 42V should be fine (according to the torque curve for your motors - different driver but probably close enough). Plus of course your driver's max voltage is 50V anyway.

JFI - are you sure your steps/pers are correct for all your axes? They're slightly "funny" numbers. X is CLOSE to an inch lead, Y and Z are CLOSE to 5mm lead and A is CLOSE to 1mm lead.

Anyway set that kernel to 25KHz and see what occurs.

Ian

1244

General Mach Discussion / Re: Motor issues

« on: July 25, 2011, 10:40:20 AM »

Hi Rod

what microstep setting are you using on your drivers? dip sw 5,6,7 and 8
also your driver dynamic current setting? dip sw 1,2 and 3

Cheers

Ian

1245

General Mach Discussion / Re: Motor issues

« on: July 25, 2011, 09:35:20 AM »

Hi Rod, Can you post any/all info (data sheets if possible) on motors, drivers, specs of power supply plus your xml please.

Cheers

Ian

1246

Newfangled Solutions Mach3 Wizards / Re: Digitize Wizard Issues

« on: July 23, 2011, 04:22:58 PM »

Open menu item Operator/Gcode Var Monitor and enter 2002 in one of the Var address boxes. Then from the MDI screen use something like G31 Z-10 to probe the styrene or whatever (the actual value (-10) doesn't matter as long as it's well lower than the surface of the styrene). Then you'll see the value of var 2002 change. That is indicating the Z position where the trip actually occured and the Z DRO will show where the Z axis actually stops.

If the difference between these two readings (the deceleration distance) is greater than the probe travel then assuming you've set your acceleration in motor tuning to the optimum value for your machine, then all you can do is lower the feedrate at which you probe. That will reduce the deceleration distance, because just like in a car, the slower you go, the quicker you can stop.

Ian

1247

Newfangled Solutions Mach3 Wizards / Re: Digitize Wizard Issues

« on: July 23, 2011, 03:33:35 AM »

The seat profile is 15" x 15". The maximum -Z dimension is -.75". Do you think a .2" step-over in the x and y axes will produce enough points to generate the surface? Those parameters generate 11K lines of code, which seems lengthy. This could be more of my ignorance showing tho.

depends on the detail of the surface you want to capture. If there's no fine detail then you could probably get away with much greater stepover. Can't see the seat from here so hard to say. Try larger stepover and if it doesn't capture the detail you want then reduce it. Until you get a feel for it you could start with an inch stepover.

The pressure exerted by the probe during the process seems to be inordinately high. It is actually dimpling the walnut original. Is this to be expected

Absolutely NOT. The probe should trip "feather light" - something is very wrong. Either your probe spring is way to heavy OR see see below.

or is there a method to adjust the response time of the software to the probe signal to reduce the reaction time and thus the pressure exerted?

Mach's response time is "step instant". That is: Mach will start to decelerate the instant a step causes a probe trip. BUT - how long it takes your probe to actually stop is a function of your machine's acceleration and probing feedrate. If the distance it takes to decelerate causes the probe to hit end travel then you'll be forcing the probe into the surface.

Ian

EDIT: To test whether your deceleration DISTANCE is less than your probe travel (which it ALLWAYS should be if you don't want to break something), probe something soft enough to give, but firm enough to trip, like a piece of polystyrene and then compare your Z DRO with gcode var 2002 when the probe has stopped. The difference is your deceleration distance at your ACTUAL probing feedrate.

1248

General Mach Discussion / Re: Blank screen

« on: July 21, 2011, 01:10:42 PM »

Thanks Tweakie - If you're bored, this might amuse you http://www.machsupport.com/forum/index.php/topic,18390.0.html. Sometimes I do wonder why I bother.

Ian

1249

General Mach Discussion / Re: Blank screen

« on: July 21, 2011, 12:11:40 PM »

I guess it must be me...

1250

General Mach Discussion / Re: Blank screen

« on: July 21, 2011, 03:56:05 AM »

Do you mean it doesn't load the screenset? I've noticed that the latest version takes longer to load the screenset than earlier versions, but it does do it after a few seconds. I'm wondering if your XML has become corrupted and points at a non-existant screenset OR your screenset has gone awol.

what happens if you do a view / load screen and browse for a screenset?

Ian