Messages

7021

General Mach Discussion / Re: Purposly Making a Weak Spot

« on: May 16, 2017, 02:04:30 AM »

Hi,
just about all the servos specs I've read, and I've looked at quite a few, comparing various units for the purposes of making a high torque
spindle have both a voltage and current coefficients. While the voltage coefficients are commonly quoted in different units and so can be
somewhat confusing when comparing units the current coefficients are almost always in Nm/A. As a matter of principle the higher the coefficient
the more torque can be achieved for a given amount of current, very useful to glean differences between models and manufacturers.

Craig

7022

Mach4 General Discussion / Re: Configuration of Mach4 for homing with reference contacts

« on: May 14, 2017, 12:21:30 AM »

Hi MaBoeck,
I have been experimenting at my machine and believe I've got a workable solution.

Mach4 core has a container for the 'home in place' flag. With the container variable false when the 'ref<axis>' or 'ref all' button
is pressed the machine will home to the switches in the order, direction and speed you specify as normal. The motion plugin/controller
actually does the work.

If however the 'home in place' flag is true for a given axis it will not drive anywhere but reset its machine co-ord to zero and home
in its current location.

Machs API has some instructions you can use to manipulate the 'home in place' flag programmatically.
The first is:

homeInPlace, rc = mc.mcAxisGetHomeInPlace(
      number mInst,
      number axisId)

which allows you to inspect the status of the flag for a given axis and:

rc = mc.mcAxisSetHomeInPlace(
      number mInst,
      number axisId,
      number homeInPlace)

which allows you to set the flag as you require. Presumably the flag will eventually be written to your profile and would become permanent
if you left it.
My suggestion for the 'ref all' button script would be:

1) Ref All---drive to home switches per normal
2)MDI---or programmed move to your desired machine home...something like
       mc.mcCntlGcodeExecuteWait(inst,'G53 G0 x500 y500 z-100')   this will hopefully put you at your desired machine home
3)mc.mcAxisSetHomeInPlace(inst,0,1)---sets 'home in place' flag for X axis as true
4) RefX--- given the 'home in place' flag the current X axis location will become X 0.
5)mc.mc.SetHomeInPlace(inst,0,0)---sets x axis 'home in place' flag back to normal
6) Repeat for Y and Zaxes as required.

Craig

7023

General Mach Discussion / Re: Purposly Making a Weak Spot

« on: May 13, 2017, 06:22:44 PM »

Hi,
I go with garylucas on this, the only AC servo I've had any experience with allows me to program a maximum current
ie maximum torque. If I decide 2Nm is the max torque my machine can handle then max current  equals max torque divided
by the torque coefficient, .8A/Nm in the case of my servo spindle.

This method will limit the torque developed by the servo but not the forces that occur if you bury a tool into a rotating
workpiece suddenly. In fact I don't see any 'shear pin ' helping you either.

Craig

7024

Mach4 General Discussion / Re: Configuration of Mach4 for homing with reference contacts

« on: May 13, 2017, 06:05:22 PM »

Hi Daz,
don't know how I missed it...

Still not sure that its going to help. My original suggestion to the original poster was to home to the centrally
located home switches using 'reff all' per normal, MDI to a more sensible machine zero and 'home in place' at that
location.

It rather looks like the 'home in place' option in Mach allows one or t'other method.

Craig

7025

Mach4 General Discussion / Re: Configuration of Mach4 for homing with reference contacts

« on: May 13, 2017, 02:49:07 AM »

Hi,
what build ESS plugin, I have 186 installed but it doesn't have home in place.

Craig

7026

Mach4 General Discussion / Re: Configuration of Mach4 for homing with reference contacts

« on: May 11, 2017, 07:42:22 PM »

Hi,
its not so much that offsets don't work but rather they're totally different to what you want.

Trying to find a 'home in place' instruction, if you are familiar with Mach3 it was an optional facility you could use to reference your machine.
I can't find a direct equivalent in Mach4. Mach4 Core does have a 'home in place' flag but the expectation is that the motion plugin actually does
the work. I use an ESS and I cannot see that 'home in place' is implemented.

I've yet to try... but from Mach4 API I found:
rc = mc.mcAxisHomeComplete(
      number mInst,
      number axisId);
which may do as you require. I will experiment some and report back.

Craig

7027

General Mach Discussion / Re: MAch 3 Input switch issues, no Switch recognition.

« on: May 11, 2017, 03:03:41 PM »

Hi,
it rather sounds like Mach is not communicating with the BoB.

To start with try to make PC/Mach/PP communicate with the BoB. To do this I suggest assigning pin 2 port 1 as X direction and enable it.
Note you don't need the motors hooked up, in fact better if there're not. With Mach enabled jog X in positive direction and note the voltage
of pin 2 with a multimeter. Now jog X in the negative direction and again measure the voltage at pin 2. If PC/Mach/PP is communicating
with the BoB and the BoB is working then the voltage should be high when jogging in one direction and low in the other.

Can you post a manual for your BoB?

Craig

7028

Mach4 General Discussion / Re: File operations, reading a line of position data

« on: May 10, 2017, 07:28:09 AM »

Hi,
I have written a macro that reads a Gcode file line by line, makes a  correction to each line, adds the corrected line
to a new file until the end of the input file.
To get the file uses a file navigation panel as above and uses the following to open:

Code: [Select]

local file = wx.wxFileDialog(panel, "Select G code File", "", "", "All files (*.*)|*.*",
                             wx.wxFD_SAVE,wx.wxDefaultPosition,wx.wxDefaultSize, "File Dialog" );
    local pathCode;
    if(file:ShowModal() == wx.wxID_OK)then;
        pathCode = file:GetPath();
    end;
I use this line to open the file:

Code: [Select]

local hin=assert(io.open(pathCode,"r"));
And these lines to read line by line until the end of the file:

Code: [Select]

while true do;
        inline=hin:read("*L");
        if inline==nil then break end;
The body of the loop has LUA string statements necessary to effect the correction I need made.
The description of the string manipulation tools can be found at:
https://www.lua.org/pil/contents.html
While the string functions seem a bit simplistic they can be combined to offer nearly all the ANSI string functions. They could very handily
be used to extract data points from a comma separated file for instance.

In fact this link is my primary resource for LUA coding help. Doesn't have any Mach API stuff or any wxWidgets but everything else LUA.

Craig

7029

General Mach Discussion / Re: Working with 6axis breakout board

« on: May 10, 2017, 06:55:24 AM »

Hi,
the drivertest sounds good. If you can get the Estop to work then it also establishes that communication between Mach3
the PP and BoB is working. While it is a simplistic test it often allows you to move on to more demanding communications
like pulse streams for stepper motors.

Quite frankly if the manufacturer doesn't have a manual and some proper circuit diagrams then I think you've bought a dud.
Its entirely hard enuf to get Mach working with a good BoB covered by good documentation, to try the same with a board that
you have no idea how it works internally is near impossible. If the manufacturer won't help you with proper documents insist they
take it back and if they don't throw the damn thing away and buy a decent one. By all means post your experience so that others
may avoid crap products.

Craig

7030

General Mach Discussion / Re: Problem getting torch to fire - Mach3, Proma TCH, Thermal Dynamics Cutmaster 38

« on: May 09, 2017, 10:44:24 PM »

Hi,
4 wires... sounds right. Two wires for PIP.

With all parts in place test for continuity between all 4 wires, there should be continuity between two of them, the PIP wires.
The other two are therefore the trigger wires.

Where the torch attaches to the machine open the cable and cut that pair of wires for the trigger. They can be extended and then
attached to the NO contacts of a relay. Note you cannot directly hook them to pin 8 of your breakout board. The 38 will probably
power one of the wires via a resistor, 1k commonly, with 24V. When the trigger is made the two wires are in effect shorted together allowing
a current, 24mA, to flow which the machine detects as trigger active and starts it pilot arc procedure. To hook that trigger wire to a breakout
board is to invite the 24V source albeit current limited to blow the output of the breakout board.

Instead use a relay, a 5V relay coil if the breakout board is 5V, a 12V coil for a 12V breakout board, etc. One coil contact of the relay will be hooked to
pin 8 and the other to 0V. The relay should now operate (click) with the output pin. The NO contacts can now be soldered to the trigger wires
as they come out of the 38.

Craig