Schmitt trigger
14 Feb 2019 21:34 #126496
by thadwald
Replied by thadwald on topic Schmitt trigger
Yes, those might work. My “need” is based on what I asked the machine operator what they would like and is also subject to part availability and number of available input pins. 
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- Richard J Kinch
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15 Feb 2019 06:22 #126524
by Richard J Kinch
Well, yes, but that's cheating because you asked how to do it with the analog wiring you already have in place.
If you're going for digital instead, then you have the option for a rotary phase encoder instead of selector. Then you only need two digital inputs for any number of selections instead of log2(selections). You keep and display the state of selection in software, so you can change it anytime without fussing with the physical wiring. You keep the satisfying physical knob, but you do lose the satisfying physical display of the setting.
Replied by Richard J Kinch on topic Schmitt trigger
An ideal solution to this would actually be a rotary selector switch with as many switch positions as you want the control to have in the first place.
Well, yes, but that's cheating because you asked how to do it with the analog wiring you already have in place.
If you're going for digital instead, then you have the option for a rotary phase encoder instead of selector. Then you only need two digital inputs for any number of selections instead of log2(selections). You keep and display the state of selection in software, so you can change it anytime without fussing with the physical wiring. You keep the satisfying physical knob, but you do lose the satisfying physical display of the setting.
The following user(s) said Thank You: thadwald
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27 Nov 2019 05:14 #151335
by csbrady
Replied by csbrady on topic Schmitt trigger
After dealing with bobble with analog overrides and erratic spindle speed displays I created a hal component to filter, add hysteresis and do rounding. The results are excellent! I set my analog feed override to provide nice crisp 5% increments. Also my spindle speed bounces around making it difficult to read. Now the display shows nice 50 rpm steps. All very stable with no bobble.
If interested the source with a makefile and a hal sample is available at bradyz.com/hyst.tgz
If interested the source with a makefile and a hal sample is available at bradyz.com/hyst.tgz
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27 Nov 2019 17:42 #151372
by andypugh
Replied by andypugh on topic Schmitt trigger
Do you want to add it to LinuxCNC?
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27 Nov 2019 17:58 #151374
by csbrady
Replied by csbrady on topic Schmitt trigger
Yes it I would like to add it to LinuxCNC. I suspect that others would find it helpful.
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27 Nov 2019 18:07 #151375
by andypugh
Replied by andypugh on topic Schmitt trigger
Are you able to submit a pull-request on github? (There are other ways, but that way is least likely to get lost). Just adding the .comp file in the src/hal/components directory will be enough, the build system will then compile it automatically. A standalone .comp should be safe for 2.8
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27 Nov 2019 21:23 #151398
by csbrady
Replied by csbrady on topic Schmitt trigger
Sorry but I don't know what a pull-request is. Can you give me some guidance?
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30 Nov 2019 01:50 #151552
by andypugh
There is a guide here: guides.github.com/activities/hello-world/
Though it isn't 100% relevant to your situation.
You would need to create a githib account, make a fork of linuxCNC, add your file, make a commit and then make a pull request.
If you think that you might get in to the habit of working on LinuxCNC then it is worth doing all that. If this is a one-off then it is probably easier for one of us to add the .comp file by hand. Though I don't think that you get a "credit" for the work that way.
Replied by andypugh on topic Schmitt trigger
Sorry but I don't know what a pull-request is. Can you give me some guidance?
There is a guide here: guides.github.com/activities/hello-world/
Though it isn't 100% relevant to your situation.
You would need to create a githib account, make a fork of linuxCNC, add your file, make a commit and then make a pull request.
If you think that you might get in to the habit of working on LinuxCNC then it is worth doing all that. If this is a one-off then it is probably easier for one of us to add the .comp file by hand. Though I don't think that you get a "credit" for the work that way.
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26 Jul 2020 15:09 #175908
by roland
The hyst component works very well.
I use it for the analog feed pots.
It would be nice if this component could be integrated into linuxcnc.
Replied by roland on topic Schmitt trigger
After dealing with bobble with analog overrides and erratic spindle speed displays I created a hal component to filter, add hysteresis and do rounding. The results are excellent! I set my analog feed override to provide nice crisp 5% increments. Also my spindle speed bounces around making it difficult to read. Now the display shows nice 50 rpm steps. All very stable with no bobble.
If interested the source with a makefile and a hal sample is available at bradyz.com/hyst.tgz
The hyst component works very well.
I use it for the analog feed pots.
It would be nice if this component could be integrated into linuxcnc.
Please Log in or Create an account to join the conversation.
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