Downdraft design questions

rodw wrote: Awesome work but remember it did not happen unless there is video. (and a full report!)

+1

rodw wrote: Awesome work but remember it did not happen unless there is video. (and a full report!)

Full report is I did what you told me to do! I still have much to learn, but this was a good day.

Next is prox sensors, then THCAD, and finally I would like to connect the VFD (that runs the blower) so that it is controlled by the Mesa card.

Nicely done!

tommylight wrote: Nicely done!

I would never have gotten this far along if it were not for the members of this forum.

Very cool. Thanks for sharing. We await the next one with smokey burning rags.... or even better a torch arc!

I think the next challenge will be to decide when the fan should be turned on and if the fan speed needs controlling from gcode.

Have a look at halui linuxcnc.org/docs/2.8/html/man/man1/halui.1.html
and also motion linuxcnc.org/docs/2.8/html/man/man9/motion.9.html

You could probably use spindle.0.on (described in motion) and the S command (spindle speed) for fan speed if its actually necessary.. I think there would be time during probing for the fan to get up to speed if you went this way. The downside is that the fan will cycle a lot. halui.machine.is−on might be a better option.

But then you could use one of the coolant pins and control it from gcode. But you may need to modify your post processor.

Watch a few pins in halshow before making a decision.
The pin you want may already be in use in Plasmac so the signal is probably already created.

By now you should know how to connect any pin in hal to an output to make things happen. If you don't, study what we've done so far as its a great example.

rodw wrote: Part of the job is already done for you in your main ini file where you will find blocks like this:

Code:

# ---setup home / limit switch signals--- net x-home-sw => joint.0.home-sw-in net x-neg-limit => joint.0.neg-lim-sw-in net x-pos-limit => joint.0.pos-lim-sw-in

Before these lines, probably where it says
# external input signals
you just need to define these signals

Code:

net x-home-sw <= hm2_7i76e.0.7i76.0.0.input-12-not net x-neg-limit <= hm2_7i76e.0.7i76.0.0.input-13 net x-pos-limit <= hm2_7i76e.0.7i76.0.0.input-20-not

This is where its important to check everything with halshow to know if you need to use the -not signal and everything is working as expected when you trigger a physical input

I installed all six proximity sensors today. Only had time to test the ones on the gantry, but they do change yellow/red in halshow. What is '-not' ? I am sure it's in the manual, my best guess is it means normal open.

Can I use a sensor for an axis home AND positive limit? I did not have limits on my old table, only home switches... so I am not familiar with exactly how limits work.