Messages

71

General Mach Discussion / Re: here is pic.of my drive test ,can you help me to see...

« on: October 18, 2010, 05:08:14 PM »

I can, but the dxf files are only text files to the jpg files on your desktop. None of the files contain any information only file locations on your computer
It would be better if you saved the information as pdf as anyone should be able to open those but you may be limiting your audience posting in dxf

...Sweep

72

General Mach Discussion / Electronics experts - Why wont this work?

« on: October 18, 2010, 05:04:00 PM »

Introduction
Building a circuit board for datums, overtravels, and spindle speed monitoring.
Will have seperate X, Y, Z homing inputs but single daisy chained overtravel.
See attached drawing of planned circuit.
CN1 = 24v taken from 250mA supply off one of my drive cards.
CN6 = 5v taken from PC parallel port
CN8 = loop to X++, X--, Y++, Y--, Z++, Z-- overtravels
CN2, CN3, & CN4 = X, Y, & Z home switches which are 2 wire type Baluff proximity switches
CN5 = Spindle speed monitor which is also 2 wire Baluff proximity switch
CN7 = Inputs to Mach3 via parallel port
Circuits for X, Y, & Z home, and spindle speed are copied from original Denford drawings but modified to accept my 24v supply.

Condition
PC on, Mach3 running, parallel port cable connected, input ports assigned, 5V supply to CN6 present, 24v supply to CN1 present.
Mach3 set to display 'diagnostics' screen. Test circuit built on breadboard.
I have tested the circuit on a simulator progam and everything seems to works fine!

Problem
When only overtravel loop is connected, osilloscope shows very clean switching of input pin on CN7 (pin1) from 0v when 'away from home' and a good 5V when 'at home.'
When only Z home is connected, osilloscope shows switching of input on CN7 (pin2) from 0v whilst in 'safe area' and a good 5v when the OT switch is triggered.
When I connect both Z home and Overtravels (haven't built breadboard with Y & X homes yet), and monitor on 2 channels of oscilloscope, both traces show 0v whilst in safe area, but when I move the Z axis towards home I only get 1v until I continue moving the Z axis to trigger the Overtravel at which point both traces hit 5v. Obviously 1v isn't enough to trigger an input to Mach3, so what have I done wrong or need to do to fix it?
As I have plenty room on my standard 100mm x 160mm blank circuit boards i'd prefer to keep all these functions on the same board.
I would also prefer not to use another 5v ouput if that is the problem as I am running out of pins and I plan a 4th axis in future.
And yes, i know I could use the Overtravels as homes but that's admitting defeat and I ain't doing that  

So, and as usual, your guidance would be appreciated.

...Sweep

73

General Mach Discussion / Re: here is pic.of my drive test ,can you help me to see...

« on: October 18, 2010, 04:21:17 PM »

You seem to have posted in dxf format. Was this intentional?

...Sweep

p.s. how do you spell 'intentional/intensional' as neither seem to look right?

74

General Mach Discussion / Re: Required spindle power

« on: October 18, 2010, 12:32:41 PM »

To follow up on my own post, I have found the site on the attached link that seems to work out power requirements though I haven't tried it out yet.

...Sweep

http://www.mapal.us/calculators/milling/CalculatorMilling.htm

75

General Mach Discussion / Re: Initial setup - spindle PWM ok, axis PWM not ??

« on: October 08, 2010, 02:04:14 PM »

Sorry for wasting everyones time, but I seem to have a bit of an issue on my homemade circuit board ...forgot to take all my transitors back to ground

76

General Mach Discussion / Re: Initial setup - spindle PWM ok, axis PWM not ??

« on: October 05, 2010, 04:11:49 PM »

Do you get a nice square wave and what are your v/div and timebase settings?

thanks ...Sweep

77

General Mach Discussion / Re: Initial setup - spindle PWM ok, axis PWM not ??

« on: October 05, 2010, 04:03:10 PM »

Hi Hood,

I probably unticked (unchecked) the spindle speed box as I thought I would concentrate on the XYZ and try solve one problem at a time.
The port address is 0x378 for port 1, and 0xdff0 for port 2.

...Sweep

78

General Mach Discussion / Re: Initial setup - spindle PWM ok, axis PWM not ??

« on: October 05, 2010, 02:27:37 PM »

Hope you can make some sense of this XML file and that the problem is obvious.
If possible I could also do with an idea of what the scope trace should look like, and what the voltage/division and time base should be set to as i'm getting nothing. i would have thought it should be, say 1v/div and a nice square wave.

thanks ...Sweep

p.s. whilst the title mentions that the spindle pwm works, it doesn't !

79

General Mach Discussion / Re: Initial setup - spindle PWM ok, axis PWM not ??

« on: October 05, 2010, 02:51:17 AM »

Ok, so it has taken a while to get back to this issue but, as my last post mentioned, I was away for the weekend in Amsterdam ...phew!!
Tried the x axis last night assigned to port1, pin1 and couldn't get a scope trace and it wouldn't step the motors. Tried active, high active low, scoped at my driver trigger board, breakout block, 25pin cable, but nothing. I thought I would see a nice clean square wave.
If someone could tell me where to find the XML file Hood mentioned I will quite happily post it.

thanks ...Sweep

80

General Mach Discussion / Re: Required spindle power

« on: September 30, 2010, 03:12:45 PM »

Thanks for the replies.
I will check out Kennemetal site to see what I can find and also have a play about with the CNC cookbook stuff, though the frontpage doesn't mention absorbed power.
i have fitted an ammeter to my machine panel that monitors supply current to the motor so if all else fails I can make some swarf doing some practical experiments.

...Sweep