Messages

1

SmartBOB controllers and dedicated accessories / PMDX-424 - Backlash comp any time soon?

« on: February 02, 2018, 08:33:55 AM »

I just ran into an issue where I needed backlash comp while running a part.  I had to tear down the setup and move the part to another machine that is still running Mach3. So I looked at the latest firmware and it appears it is still not implemented yet.  Any plans for this in the near future?

2

SmartBOB controllers and dedicated accessories / Re: Homing - 0.050" Move

« on: January 04, 2017, 05:08:29 PM »

Hi, I noticed there was an update in December.  Is the homing move adjustable in this new version?

3

SmartBOB controllers and dedicated accessories / Re: Homing - 0.050" Move

« on: October 21, 2016, 08:17:41 AM »

Sorry for the late reply, I must not have email notifications set up.

Yes it is over 1 million counts per inch.

4

SmartBOB controllers and dedicated accessories / Re: Homing - 0.050" Move

« on: September 20, 2016, 01:58:05 PM »

Thank you!

5

SmartBOB controllers and dedicated accessories / Re: Homing - 0.050" Move

« on: September 20, 2016, 01:07:27 PM »

The problem is that the axis movement and shaft rotation are not 1:1.  The shaft is about 4" diameter.  It has to rotate 37.8947? to move the axis 0.0010".  If you calculate the linear distance the shaft moves per thousandth move in the axis, it comes out to about 1.3228".  So in other words,  .0010" on the axis translates to 1.3228" along the switch - or - for the shaft move along the switch .050" The axis would have to move .000037"

Attached is a drawing of a similar machine.  Item 120 is the home switch.

6

SmartBOB controllers and dedicated accessories / Re: Homing - 0.050" Move

« on: September 20, 2016, 11:40:50 AM »

    I will just manually home the machine for now.  Will there be an option to change this value lower in a future release?  Attached is a pic of the existing switch.

7

SmartBOB controllers and dedicated accessories / Re: Homing - 0.050" Move

« on: September 19, 2016, 09:30:23 PM »

That would probably work, but I would hate for mistakes to be made on a final grinding operation over a number translation issue.

8

SmartBOB controllers and dedicated accessories / Re: Homing - 0.050" Move

« on: September 19, 2016, 04:41:20 PM »

Well the home switch on this machine is not the traditional setup. The switch is not on the actual axis because it is not practical on this machine.  There is a large shaft that turns the feed screw, the shaft has a protruding finger that hits the home switch when it is in the right spot.  It has a decent length of engagement on the switch, but it is probably only 0.001" - 0.002" (just a guess) of travel on the axis.  It has a very fine feed screw.  I am not sure the model of the switch,  but they look like high end switches.  They are from the original control unit made by GE.

9

SmartBOB controllers and dedicated accessories / Homing - 0.050" Move

« on: September 19, 2016, 03:45:49 PM »

I am trying to set up homing on my machine and from what I can tell the PMDX-424 wants to travel 0.050" past the point where it sees the home switch.  My axis only has .060" of travel because it is a very fine grinding wheel outfeed. This causes the machine to bury the axis before homing is complete. Is there a way to change this setting?

10

SmartBOB controllers and dedicated accessories / DRO from encoder input - PMDX-424

« on: August 12, 2016, 04:09:07 PM »

     I have an DRO panel set up that is reading my encoder input just fine.  I would like for the DRO to display inches instead of encoder pulses.  What type of script would you use and where would you put it?  I understand how to calculate my pulses per inch, I am just unsure of which type of script would be best to interact with this input.

11

SmartBOB controllers and dedicated accessories / Re: PMDX424 - Controling pneumatic Z-axis?

« on: May 18, 2016, 01:30:43 PM »

Bob - Could you post on example on how to set up a DRO with these inputs when the new plugin is released?

12

SmartBOB controllers and dedicated accessories / Re: PMDX424 - Controling pneumatic Z-axis?

« on: May 11, 2016, 10:30:02 AM »

Thanks Bob.  Is the PMDX424 capable of reading the encoder signal to display as a DRO in Mach 4?

13

SmartBOB controllers and dedicated accessories / PMDX424 - Controling pneumatic Z-axis?

« on: May 07, 2016, 08:04:05 AM »

Posted this in the Mach4 forum but maybe this is a better place:

"I am in the process of re-retrofitting a Jig grinding machine I did a long time ago.  The machine is sort of a hybrid between the old control and Mach3.  Mach3 controls the X,Y and U (wheel outfeed) Axis.  The old control still handles the Z axis which is pneumatically driven with glass scale feedback.  I would like to take control of the Z in Mach.  This axis does not need to be precision controlled, I just need to be able to set and upper and lower limit so the Z axis will reciprocate between those limits.  I have done something similar in LinuxCNC using a Moog hydraulic servo valve with glass scale feedback to control the position of a hydraulic cylinder, but I have not done this in Mach3 or Mach4.

I am thinking I should take control of the relays that operate the pneumatic solenoid and use a script to monitor the position of the axis.  Once the position hits the upper or lower limit it would activate the relay to change direction.  Does this sound feasible? Is there a better way to do this?"

I understand that Mach4 only monitors the signals at 10Hz. The axis moves at a max of 250ipm. Would there be a better way to set this up with the PMDX424?

Here is a pic of the current control: