What do I need to be able to probe Z.with 411 and g540

[crchisholm]

I want to be able to set Z zero with a probe using the PMDX 411 and gecko g540.  Can someone point me in the right direction for something that won't break the bank?

[Steve Stallings]

Nothing fancy is needed, just a flat conductive plate for the tool to touch.
The underside of the plate should be insulated so that it cannot touch
any metal parts of your machine. You will need a wire connection from
the plate to one of the inputs on pins 1, 2, 3, or 4 of the green screw
terminal strip on the back of the G540 and a wire from the the power
Gnd on pin 12 of this same terminal strip to a clip that can be attached
to the cutting tool while probing. Note that this wire will share the
connection from your power supply for the G540.

You will need to configure your software to monitor parallel port pin
10, 11, 12, or 13 to see a "digitize" input. You will also need to know
the thickness of the touch plate so that your touch-off macro can
correct for this offset.

See the MachSupport forums for information about a tool length
touch-off macro.

[Fishcat]

Steve, What am I doing wrong that makes my Z go + instead of - while finding the material top?  Thanks, Bill

[Steve Stallings]

Without knowing what you are doing, I have no way to guess what you are doing wrong.

Please post the commands that you are using.

[Fishcat]

Sorry Steve, I am pushing the lower right icon on the Touch popup box. I was expecting Z to come down and touch my puck to set Z for this work piece but it went up (minus) instead. Sounds like something really simple that I should know already.  Thank you, Bill

[Steve Stallings]

It sounds like your perception of CNC axis definitions is confused and
as a result you have mis-configured the direction of movement of the
Z axis. The positive direction of the Z axis should increase the distance
from the cutter to the work piece. See:

http://www.qhunt.com/2015/10/how-to-indentify-axis-in-cnc-milling.html

[Fishcat]

Well, at least I did know that Z+ is up and my jog buttons are correctly oriented. Where should I look to tell the the Z that the touch pad is Z-?

[Fishcat]

Ok. Got the polarity direction thing sorted out. Next project is Homing. I can turn their lights on by turning off the Active Low switch but my machanical switches don't seem to be communicating with the board. Sorry to bug you with such simple crap. I'll see if I can work this one out without smoking the board.   Bill

[Steve Stallings]

Your mechanical switches for homing connect between the inputs on the
G540 and ground on the G540.

You can monitor the status of the signals at the PMDX-411 by using the
Real Time Signal monitor available in Config > Plugins > PMDX SmartBOB
by using the button in that dialog to launch our monitor panel. The panel
can left open while running, and can be moved around on the screen so
it is out of the way.

Remember that X Home and X-- (and other limit inputs) are different signals
inside Mach4 and you may need to assign the same PMDX-411 input signal in
several places if it has more than one meaning.

[Fishcat]

Sorry Steve, I kind of butted in to this thread. I have the 424 and 407 boards. I have homing switches and ++ and -- switches. It looks like there are 8 Inputs on J16 and J17 but some are already assigned as I am using your PMDX-424-Sample as as a base for my profile. Can these do double duty if so assigned in the Inputs Configuration? Also do I need to wire the +12V and Neg on J16 and J17?    Thanks, Bill

[Steve Stallings]

Mach4 allows a single input to have multiple events associated with it.
For example, it is common to use a single input for a switch that is
interpreted as both X Home and X-- limit. If multiple switches are to
be fed to a single input they must be wired such that the input will
see either switch activate. Normally closed switches should be wired
in series. Normally open switches should be wired in parallel.

When a single input has multiple meanings, you need to put the
same configuration information beside each of the intended meanings
in the table of Input Signals in Config > Mach.

You are free to remove example input configurations, but should keep
one for E-Stop if possible.

The GND  on J16 and J17 are required as the reference for proximity
sensors or as the return for mechanical switches. The +12V can be
ignored if not needed to power proximity sensors. Proximity sensors
can be externally powered, but the GND connection is still needed.
Proximity sensors must be NPN to work directly with the PMDX-424.

[Fishcat]

Well Steve, I believe I have it all connected. They will light up on the Machine Diagnostics page when I change them to Active High and go back out on Active Low. Alas the switches do nothing to the program when I push on them. I feel that I am missing a step on the setting up.

[Fishcat]

1 more.   I ran grounds to J16 and J17Please tell me what I haven't done yrt.  Bill

[Steve Stallings]

Your first screen capture shows setups for the Mach4 signals named Input #1, Input #2 etc.
These are NOT the same thing as the inputs number 1, 2, etc. on the PMDX-424. They are
signals that can be accessed by LUA macros in Mach4, but have nothing to do with Home
or Limit sensing. You do not need to assign signals to them, though it should not be causing
the problem that you have.

You can monitor the status of the signals at the PMDX-424 by using the
Real Time Signal monitor available in Config > Plugins > PMDX SmartBOB
by using the button in that dialog to launch our monitor panel. The panel
can left open while running, and can be moved around on the screen so
it is out of the way. Please try this to determine if your signal inputs are
making it to the PMDX plug-in.

[Fishcat]

I apoligize for my ignorance on this stuff Steve but I wired J16 and J17 to ground but no go. So I looked at the switches and they have 0V opposite the wires going to the 424. Will I screw up the board if I put 0V where the ground is designated? Or should I get a 12V source for J16 and J17 12V pin. Bill