Messages

161

General Mach Discussion / anyone here from Johannesburg South africa??or south africa??

« on: April 10, 2015, 10:27:45 AM »

Hello there - please introduce yourself !!
I live in Kensington

162

General Mach Discussion / Re: ative low or active high??

« on: April 10, 2015, 10:24:36 AM »

OK Stirling now i got it
the reference is in section 4.6.3 and refers to the general settingh up of stepper motors.
the reference is as follows  (typo's excluded)
"Stepper drive electronics usually use Active  Lo configuration mach3 should be set up so these outputs are acrtive lo
..... " it goes on to say that inverted setting up will resuly in very rough and unreliable running

163

General Mach Discussion / Re: ative low or active high??

« on: April 10, 2015, 06:35:13 AM »

Hello There
Page 4.7 of the mach3 turn manual-- sorry will be more precise next time
I will find the detail of the pin no tonight when I get home and put that in

regards

fred

164

General Mach Discussion / Re: ative low or active high??

« on: April 09, 2015, 03:54:15 AM »

Thanks David-- the machine is functioning OK so looks like I was worrying about nothing
I am at work at the moment and will check up tonight to see if I have perhaps
misinterpreted the tick or the cross-.
many thanks

165

General Mach Discussion / qestion on pvmbasefreq

« on: April 08, 2015, 01:27:51 PM »

Hello chaps
in the setup instructions it is recommended in ports and pins that pvmbase frequency be set
to between 5 and 10 for optimum performance.
The installer who installed my OMRON PVM set the base frequency to 500
what effect would this be having on the running of the machine??
regards

fred
 

166

General Mach Discussion / ative low or active high??

« on: April 08, 2015, 01:17:49 PM »

having now (after many months) a basic understanding of gcode,Mach3, Ports and pins etc and my machine
sort of running ok i decided to start again at page 1 of the manual and go through it step by step for about the
umpteenth time!!

This is the first of a few questions concerning some thing needing  explaining
Quite a few guys have been helping and each with his own suggestions resulting in
some unknown differences being made to the setup and settings.
 
Machine setup Page 4.7 says i must tick the active low button on in ports and pins  but i see my
setup has active low off ?? is this a serious issue?
What difference does it make?? anything i could detect when using the machine

all comments gratefully acknowledged

fred evans

167

General Mach Discussion / Re: pulley ratio ,feedrate and motor tuning

« on: April 06, 2015, 12:13:39 PM »

thanks Jim-- i have done a step loss  program but didnt mix g0 and g1 like you suggested so i will try that

You mention "slowing down the rapid" > Am i correct in assuming that this is done by slowing down
the velocity slider in motor tuning dropdown??

thanks

fred
 

168

General Mach Discussion / Re: pulley ratio ,feedrate and motor tuning

« on: April 04, 2015, 03:09:04 AM »

Thank you rich for this info-- My steppers are Kelling i know not what but i will try and
identify then first then i will go through your advice in detail.
I have not made any changes to the electronics so i presume that i am still using
the voltage that the breakout board is putting out. I am presuming that this voltage
will be a constant?? Can i take a voltage reading by connecting a meter  to the stepper
wires and which wires must i use ?

169

General Mach Discussion / pulley ratio ,feedrate and motor tuning

« on: April 03, 2015, 10:48:31 AM »

Hello Chaps,
I am having a lot of trouble getting repeatable sizes on my lathe x axis.

I dont know how to tell if steps are being lost but i suspect that this may be the
cause of the problem.

If steps are being lost can it be heard or how can i tell. When I do the steploss
check ( backwards and forwards 50 times to return to a zero point) it seems to be
ok - but i do not know what happens when the machine is taking a cut.

I think I might have found a possible cause.

when I mounted the stepper motors i didnt understand the torque characteristics
of the stepper. In my wisdom I decided to gear down by means of toothed belts
by a ratio of about 1 to 3 - the smaller pulley being on the motor. In theory i thought
that the gearing would prevent overloading of the stepper.
But now it has been pointed out to me that the stepper is at its most powerful
at very low revs and there is a decided reduction in torgue as very speed increases.

Am I correct in assuming that if I reduce the gearing and bring it 1 to 1 that i will
be better utilizing the torque characteristic of the motor?
My steps per mm will be much less and the motor would then be running at lower
revs at which the motor is delivering its maximum torque?.
At low revs  is there any chance of overheating the motor?

Best regards and thank you

Fred Evans



  

170

General Mach Discussion / Re: wizards and feedrate per rev

« on: April 03, 2015, 10:27:28 AM »

Thanks rich - i did it with the idboring wizard and the setup string was changed after posting code
as was suggested
I am  posting another topic about pulley ratio- please have a look at ity

best regards

fred