Disabling Axis

[rojhan]

My stepper drivers are setup to require a high on ENA+ relative to ENA- to *disable* the drive (intuitive, eh?).

I've been intending to disable all motors (axis and spindle) unless UCCNC is in control and have done so by adding a C11G as a breakout board and using the charge pump/SCHP. This is working fine. If the computer is off, UCCNC isn't running, or the RESET button in UCCNC is active, the steppers can spin freely.

To support disabling the stepper, I have the enable output pins pulled high with a 1Kohm resistor. XYZ is on one enable pin and A is on the other. ENA- goes to ground. My intent is to be able to disable the A/rotary axis and physically disconnect it when not in use and avoid any remotely possible damage to the drivers when enabled but the stepper removed. What I have found is that enable/disable on the A Axis (XYZ as well) does not actually follow the configuration of the enable pin active high/low. If the RESET button is not active (not reset) the stepper remains enabled even if the axis is disabled regardless of the configuration of the high/low configuration of the enable pin.

Computer power off, motion controller (UC400ETH) disconnected from network, UCCNC not running, or UCCNC in a reset state: Stepper drivers are disabled and steppers spin freely.
UCCNC not in reset, regardless of axis disabled and high/low configuration of the enable pin: Steppers are locked.

It looks like the axis disable button only prevents UCCNC from sending step/direction to the stepper and doesn't touch the status of the enable pin. Is this by design/intent or is it a bug?

If it's by intent, how do I submit a feature request to add this functionality?

Thanks,

[fsli]

My intent is to be able to disable the A/rotary axis and physically disconnect it when not in use and avoid any remotely possible damage to the drivers when enabled but the stepper removed.

The Enable pin tracks the setting of the Axis Enabled check box.

You need to create a new profile which unchecks the A axis "Axis Enabled" box. When working on a project that does not use the A axis, select the profile which does not have the axis enabled. When working on a project which does use the A axis, select the profile which has it enabled.

For example:

[rojhan]

The Enable pin tracks the setting of the Axis Enabled check box.

You need to create a new profile which unchecks the A axis "Axis Enabled" box.

Please read the full post. That is not the behavior I'm seeing.

[fsli]

Please read the full post.

I did, but I'm having difficulty understanding whether you meant the enable/disable based on the output pin setting, or the enable/disable based on the Axis Enabled checkbox.

If you zero the Enable pin number and port, then UCCNC has no way of knowing how to signal to the breakout board that the axis needs to be enabled. So, if you're saying that with the Axis Enabled checkbox cleared, and the Enable pin/port zeroed, that the stepper for the A axis is still getting powered up, then you have a wiring problem.

Are you setting up a different profile, or testing different configurations of the same profile? Are you remembering to Apply Settings between each configuration change?

In that condition (Axis Enabled clear, Enable pin/port zeroed), what does the LED on the C11G for your A axis enable output show?

From what I can tell, the C11G outputs are high by default, so I don't understand the need to pull them up. What stepper driver are you using?

[rojhan]

I thought the C11G was high on disabled as well, but maybe not strong enough for my steppers (need at least 7ma to drive the optoisolator). I do see 5V with nothing attached to the pin. With just the C11G output, the stepper driver remains enabled whether C11G is high or low. If I add a (presumably) stronger pullup, the driver goes to disabled. It may be because I'm paralleling XYZ enable on one pin (and A on another).

With enable, step, and direction pins defined per axis, the stepper drivers remain disabled unless UCCNC is not in reset; UCCNC has to be running and NOT in reset for the outputs to be enabled by the charge pump.

Once the outputs are enabled, however, the stepper drivers remain enabled regardless of the per-axis "Enable" status (regardless of whether the enable pin is active high or low in the configuration).

What's really interesting now, based on a comment you made; I zero'd out the enable pin for the axis and the output pin is being driven low when UCCNC is not-reset. It's happening for the other axes as well. So, something other than UCCNC seems to be driving the pin low (or UCCNC is driving everything low by default).

More to come as I dig deeper....

[dezsoe]

What is the version of UCCNC and which screenset do you use?

[rojhan]

What is the version of UCCNC and which screenset do you use?

I'm using the defaultscreenset with no modifications.
Software version 1.2113
Firmware version: 1.1500
Hardware version: 1.000
API version: 2.1820
Device type: UC400ETH

Additional digging points to not a UCCNC problem:
- If I disable the charge pump input on the C11G, the steppers lock
- Floating/disabled output on disconnected output pins is only 1.6-1.7V when the C11G is disabled and 0v when enabled.

[rojhan]

This is somehow tied to the charge pump on the C11G.

I've normalized all wiring; no pullups. COM is +5V and goes to ENA-. Enable pin goes to ENA+. UCCNC is set enable active high. Stepper drivers are DM556T.

With the charge pump disabled (C11G permanently enabled), behavior is as expected (other than a blip when UCCNC loads - and I'm trying to get rid of the blip).
With the charge pump enabled (C11G only enabled if it sees 12KHz from UCCNC), but no 12KHz, the enable pin is 0.3V and the steppers are locked. Loading UCCNC and deactivating the reset button brings the enable pin to ground.

No other outputs or inputs are connected on the C11G.

[fsli]

COM is +5V and goes to ENA-. Enable pin goes to ENA+.

This is incorrectly wired. You need to connect the ENA- to ground. Leave the output pin you're using for Enable connected to ENA+.

[rojhan]

COM is +5V and goes to ENA-. Enable pin goes to ENA+.

This is incorrectly wired. You need to connect the ENA- to ground. Leave the output pin you're using for Enable connected to ENA+.

Yep. Mistake/typo.