Author Topic: Physical buttons for plasma  (Read 82776 times)

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Offline Hood

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Re: Physical buttons for plasma
« Reply #340 on: April 30, 2016, 06:11:27 AM »
Saw this fan on eBay, any thoughts on its suitability?
http://www.ebay.co.uk/itm/Industrial-Duct-Fan-Cased-Axial-Fan-Commercial-Extractor-450mm-4-Pole-/191541803309

Also anyone know where I can get 15 core (or more) curly cable, suitable for a hand held pendant,that can extend to 3m? Have found lots but none can stretch to that length.

Hood

Offline stirling

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Re: Physical buttons for plasma
« Reply #341 on: April 30, 2016, 07:30:57 AM »
Re: the cable: You could always stick a jack box at the mid point and plug your coiled cable into that - voila - you'd only need 1.5m.

Or - how about using infrared - no cable needed.

Offline Hood

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Re: Physical buttons for plasma
« Reply #342 on: April 30, 2016, 01:21:50 PM »
I had thought about having the wire halfway and strapped along the front of the table and may end up doing that. If I do then I probably won't require curly cable as I can make it a good fit so it doesn't sag.
Regarding IR, not keen on wireless for controlling a machine and as this is with the CSMIO MPG module I not even sure if  it would be possible.

Hood

Offline robertspark

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Re: Physical buttons for plasma
« Reply #343 on: May 04, 2016, 09:02:22 PM »
Well tried bench testing to minithc (thought it would be easy... First failing)

Basically fed it a slow 2v square wave at less than 0.2 hz.

This allowed me to see that it was reading the voltage about 2 volts higher than it was (calibrated scopemeter), although this is without the plug in pmx45 50:1 adapter.... Hence there may be some effect from the filter circuit in that on the read voltage.

Unfortunately I was not able to get a specific cutoff frequency of saturation, and it seemed relatively low, but this I suspy was from feeding it a 2v to 2.4v square wave switching from zeo to the set voltage which is a little unrealistic given the voltage would be jumping from 0v to 100 or 120v on an increasing frequency.... Basically I need to stop a smaller varying input voltage 0.02v to 0.05v .... With an offset of 2.4v....

And I've not got the inclination at the moment....but may come back to it
Rob

Albert Einstein ― “If you can't explain it to a six year old, you don't understand it yourself.”

Offline Hood

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Re: Physical buttons for plasma
« Reply #344 on: May 06, 2016, 02:56:17 AM »
Oh well, suppose we will find out how well it performs once one of us gets it hooked up to the plasma :D

Hood

Offline Hood

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Re: Physical buttons for plasma
« Reply #345 on: May 07, 2016, 05:17:01 PM »
I have not got power to the cabin yet other than running an extension lead. I am waiting on the boatyard crane to move the cabin round a bit so access will be easier for material, once they do that then I will run in some 3 phase.
 Today however I decided to power up a drive at a time from single phase supply.
 
 The racks and pinions on both axes still need adjusted properly but it was fine for this test.

Got the Y set up first, did a rough tune and set up the Index homing. It went reasonably well but I am probably going to have to drive both sides as at 20m/min rapids and  jogging back and forth in very short bursts I could see the far side getting out of shape. I will see how it performs at the fastest I will ever cut, probably 6-7m/min, and if it looks reasonable I will delay driving the second side until later.
I can then decide whether a rod/tube  through the gantry or a motor on the other side will be the best way to proceed.

Anyway here are a few vids,
First is the X axis going at roughly 20m/min.

https://www.youtube.com/watch?v=SfoXmz3j8Jw

Next is Y axis doing the same

https://www.youtube.com/watch?v=ZeuYbyCnFs0

Lastly  it is the Y axis doing the Index homing.

https://www.youtube.com/watch?v=bof2LoSPxoE

As can be seen in the vid I am monitoring the encoder via a netbook connected to the drive, the encoder count is spot on each time, jitters between -1996 and -1997 encoder counts. The tuning is not perfect yet but it was good enough for today's tests.
The prox I am using to trigger the Index homing is on the non-driven side so it shows that there is not any flex at the lower speeds of the homing (5m/min)

Hope to get the Z Axis tried out tomorrow, hopefully the tiny motor will be up to the job.

Hood

Offline Davek0974

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Re: Physical buttons for plasma
« Reply #346 on: May 08, 2016, 03:24:29 AM »
Looking good, don't forget - it's not the speed that will stress it but the acceleration. ;)
Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Physical buttons for plasma
« Reply #347 on: May 08, 2016, 05:22:22 AM »
Yes, well mainly, velocity will also affect things as having a very high accel but a lowish  velocity will likely not stress things as much as it would having a higher velocity with the same accel.
At the moment I have it so it takes 1/3 second to get the 20m/min

Hopefully will get the Z tested out this afternoon, may even get a chance to try all 3 axes together, that will depend on whether the extension cable can handle things, not worked out what the current draw would be off of one phase.

Hood

Offline Davek0974

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Re: Physical buttons for plasma
« Reply #348 on: May 08, 2016, 08:39:01 AM »
As a general setting I have found the 1/10th rule to work pretty well - say you have 2000mm/min velocity then you set 200mm/s/s acceleration.

From my own tests it works pretty well as a bog-standard setting to work up from.
Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Physical buttons for plasma
« Reply #349 on: May 08, 2016, 03:13:39 PM »
Happy to say the wee motor on the Z works well.
Have it set to 5m/min and 5000mm/s/s rapids.
Here is a vid of it homing with a G28.1 and then doing a few up and down rapids.

https://youtu.be/ZEd4OS09KM8

Just had enough time to set up the home to current value in the drive and give it a quick test. It is looking promising but I will need to do some more testing to make sure it will be good enough for touching off.
Here is a vid of the initial test.

https://youtu.be/8oM4dTONGyc

Torch lowers, touches material, current increases because motor is starting to push against the material and it then stops and  sets that as home in the drive, it then backs off an amount I have preset.

Hood