axis behavior with external feed override

Hi,

I'm adding a pendant to my mill and was wondering what will happen if I have a feed override pot attached to my mesa hardware. Let's say the screen slider is at max ipm and the pendant control is set at a low ipm setting what is the expected behavior with axis?

I'd like to keep mouse control over the screen sliders and be able to use the external buttons/rotary increase/decrease feed rate as well.

How do you deal with the different settings between the slider and the pot? I assume a rotary pulser instead of a pot would work best.

Same question applies to axis select (xyz) and jog increment select. Last, does the pendant have to be powered off to let the mouse be used for selection?

Thanks!

AXIS sliders will respond to other UIs requests for change.
The jog rate will not though as linuxcnc has no jograte message.
AXIS has some HAL pins to help:
linuxcnc.org/docs/2.7/html/gui/axis.html#_axisui_pins
Note you cannot set the active axis (in AXIS) externally.

so in general, the rules is last change wins. This can be broken by some programs that constantly send updates.
And yes if you want the screen sliders to be used with real knobs - encoders work best or up/down buttons - anything that the position does not represent an absolute setting.

halui is the program usually used for external control - you could also write a python program too.
another way would be to use a pendant that acts like a keyboard and use keyboard shortcuts to control AXIS.

Chris M

cmorley, thanks for your response. Can you elaborate on what you are saying regarding the jog rate will not respond? Will it not update the gui slider based on external knob position or are you saying I can't control the jog rate externally at all?

How about the feed override? That's the one I'm needing more.

Also can you explain further what you mean by you cannot set the active axis (in AXIS) externally.
The link you posted shows the axisui pins for jog selection.

What I'm trying to do is determine what buttons/switches I can add to my pendant I'm designing. I have implemented MPGs before but always used the mouse and gui to select jog increments /selected axes. I'd like to have the basics now on a remote pendant.
I currently have some nice grayhill rotary switches that I'm thinking of using with a mux component. I have a pot for feed rate (need a pulsing encoder type instead, recommendations??) to adjust feedrate during a program execution.

Maybe a workaround for the last change wins rule is to put the pendant on a momentary switch for axes select and jog increments?

OT-CNC wrote:

cmorley, thanks for your response. Can you elaborate on what you are saying regarding the jog rate will not respond? Will it not update the gui slider based on external knob position or are you saying I can't control the jog rate externally at all?

Jog rate in AXIS will not update based on any other external control.

OT-CNC wrote:

How about the feed override? That's the one I'm needing more.

Yes overrides will.[/quote]

OT-CNC wrote:

Also can you explain further what you mean by you cannot set the active axis (in AXIS) externally.
The link you posted shows the axisui pins for jog selection.

Those pins are output so you can use them to tell what AXIS says is active but you can't tell AXIS to change them from something else.
They were intended for control of a single MPG for jogging

OT-CNC wrote:

What I'm trying to do is determine what buttons/switches I can add to my pendant I'm designing. I have implemented MPGs before but always used the mouse and gui to select jog increments /selected axes. I'd like to have the basics now on a remote pendant.
I currently have some nice grayhill rotary switches that I'm thinking of using with a mux component. I have a pot for feed rate (need a pulsing encoder type instead, recommendations??) to adjust feedrate during a program execution.

AXIS really doesn't play nice with external controls - it was never intended to. So some compromise is required.
-You can set an external jog rate using halui but it will be separate from AXIS- all AXIS controls will use AXIS jograte, all halui controls will use halui jograte. - really means you must learn to use the separate controls only.
-You can use HALUI and a MPG to control feedrate, rapid and maxvelocity override and AXIS will show the changes and changing AXIS will change the setting - this works well.
-You can use a keyboard emulator (or a hacked up keyboard) to use AXIS's short cuts to control AXIS.

OT-CNC wrote:

Maybe a workaround for the last change wins rule is to put the pendant on a momentary switch for axes select and jog increments?

there is no way to control AXIS's idea of selected axis and selected jograte. You would be using HALUI's idea of selected axis and selected jograte. (I lied a bit you can connect AXIS selected axis to HALUI, so that AXIS will select HALUI's active axis)
Whew I hope your not too confused!

AXIS is a lot like Apple products -its great if you like what it does, it does them very well - but it does not like you trying to do anything else.
Hopefully others will chime in with more real world answers to workarounds.

Chris M

Chris,

Thanks for your help. So it looks like HALUI will work for what I want and it will update axis's gui to reflect the external control's switch positions. My confusion now is, will I still be able to use the mouse for those controls on the gui or am I locked into physical buttons only?

If you uses an MPG and HALUI for overrides then AXIS controls will still work (you can use either)
If you use a rotary switch and HALUI - i can't remember exactly either AXIS controls would not work properly or it will be last-one-wins.

AXIS says 'set it to this number' but also listens to see if anyone else 'set it to a number' and will reflect that.
an MPG basically says 'whatever it is now add a little to it'
a rotary switch with HALUI says 'set it to this number' but can not change based on anything else (obviously)

Chris M