Machine Hold 126 REV C

[todd432]

Hi
I'm building my new controller using the 126c board 134 board, ESS & 107 spindle card pmdx.

Now I want an Estop to kill everything in the box, but I also want to just stop motion at times and resume. And be able to free wheel the gantry with out shutting everything down.

The Estop I figured out ( I think Lol) But the stop and resume (Machine hold) not so sure.... I think it might be best to use Mach for this function. The board has an M Hold, function should I use this? Or just use the software or both.

The 126 also has the disable function for the drives. I believe this will give me the free wheel of the gantry with out restarting Mach. Just re Zero all the axis

Need some input on this
THX
Todd 

[Steve Stallings]

The best way to stop motion and resume is to use the Feed Hold function of Mach3.

Machine hold is more of a safety interlock that allows the machine to power up, but
be prevented from moving but also not issue an E-Stop. This is intended for
machines that have a separate "Enable" button that must be pressed after power
is on, but before the control is allowed to move. Mach3 does not fully support this
concept.

In order to free wheel your motors, you should use the Motor Disable input on the
PMDX-134 as shown in Figure 5 on page 8 of the PMDX-134 manual. Even then you
may not find the effort to move the machine by hand is what you expect. Stepper
motors have residual holding torque even when disabled.

Consider using Mach3 to jog the machine and then reset the offsets or origin as
needed.

[todd432]

Thanks Steve

That's just what I wanted to know.
I will have proxy switch's on the machine to set zero...... but I just know I'll want to free wheel the gantry by hand some time in the future.
That's how I set zero now... by hand. Your right it not like rolling it with out the motors engaged.

One more question.....If you use the software Estop in Mach3 (click the button on the screen). Will it shut down the whole box?
Or like Feed hold but with out the resume feature?

Oh and another question.....On the 134 board the power in, should I put a fuse before the terminal?
I have seen other controllers fuse each driver individually when wired with out the 134 board. I know the 203v's have fuses, but it would be a lot easier to change outside of the drive.

If I fuse the 134 what size? 5 amp or 20 amp or some were in between? I am fuesing the power supply with a 20 amp breaker

[Steve Stallings]

When you click on E-Stop on the Mach3 screen, the PMDX-126 will only know
about it if you have the charge pump function enabled. If you DO have the
charge pump function enabled and Mach3 is configured to NOT provide the
signal for the charge pump when it is in reset, then the PMDX-126 will turn
off all of its outputs including the relays and PMDX-107 spindle controller
if present. This is the normal configuration that we recommend.

When E-Stop is presented directly to the terminals on the PMDX-126, it
will always turn off all of its outputs in response to the E-Stop regardless
of what Mach3 is doing.

We recommend that you fuse the AC mains side of the power supply for
the stepper motors. This avoids issues with back EMF from the motors
not having anywhere to go. If you do choose to fuse the DC input to the
PMDX-134, you will need to choose a fuse that can handle the correct
current for your motors. This is typically 2/3 of the sum of all the motor
currents. If all 4 of the Gecko drivers are running at a full 7 amperes,
then a 20 ampere fuse would be recommended. The internal fuse in each
G203V is 5 amperes.