Voltage Scale and Auto Volts

More
20 Dec 2021 23:46 - 20 Dec 2021 23:50 #229582 by phillc54
Hmm, there certainly is some weird behaviour there.

Can you make a backup of your config from the parameters tab and post it.

EDIT: I re-read your post and you say that the voltage is falling as the torch is rising, I would have expected the opposite.
 
Last edit: 20 Dec 2021 23:50 by phillc54.

Please Log in or Create an account to join the conversation.

More
20 Dec 2021 23:55 #229583 by CFE
Replied by CFE on topic Voltage Scale and Auto Volts
Hi Phil,

I have attached a backup of the config.

Well, exactly, we would expect to see the THC lowering the torch as the voltage drops, but instead it keeps moving up. I watched it again and I can see the Z-axis moving up, voltage drops a couple of volts but the THC is not correcting. That is what baffles us.

Cheers, Peter

File Attachment:

File Name: Plasma_V1....2.tar.gz
File Size:14 KB
Attachments:

Please Log in or Create an account to join the conversation.

More
21 Dec 2021 00:00 #229585 by tommylight


EDIT: I re-read your post and you say that the voltage is falling as the torch is rising, I would have expected the opposite.

 

That is not the symptom, it is the cause.
The voltage is falling so the torch is raising to compensate.

Please Log in or Create an account to join the conversation.

More
21 Dec 2021 00:00 #229586 by phillc54
Normally if the voltage drops then the torch is raised, which is what you are describing is happening. As the torch is raised the voltage should increase but because the voltage is falling THC is trying to raise the torch.

Please Log in or Create an account to join the conversation.

More
21 Dec 2021 00:09 #229587 by CFE
Replied by CFE on topic Voltage Scale and Auto Volts
Rigtho, so I can clearly see the torch rising and at the same time the voltage falling instead of increasing. This got me stumped.

Can it be that I have to switch the Z-axis scale ?

Please Log in or Create an account to join the conversation.

More
21 Dec 2021 00:10 #229588 by tommylight
Do you access to a DVM with memory?
Also can you do a hal scope of the encoder velocity and set it to trigger when the velocity drops?
This has all the makings of a bad contact on the plasma cutter or THCAD.

Please Log in or Create an account to join the conversation.

More
21 Dec 2021 00:18 #229590 by CFE
Replied by CFE on topic Voltage Scale and Auto Volts
Hi Tommy,

I will have a go with HAL Scope. The plasma cutter is only a couple of months old, I like to think that should be alright. And don't forget, this thing cuts no worries on 12 and 16mm plate, with the THC working (and working fast too, pretty amazing to see). But as soon I get to 25mm the thing plays up.

Another thing I just noticed : I am cutting test pieces, rectangular 250x25mm with 5mm corner radii. Sometimes when it comes out of a corner the torch lifts up, and then sometimes it doesn't. Can velocity anti dive or void anti-dive interfere in any way ? I am just clutching straws here.

Cheers, Peter

Please Log in or Create an account to join the conversation.

More
21 Dec 2021 01:32 #229592 by CFE
Replied by CFE on topic Voltage Scale and Auto Volts
Hi all,

Just out of curiosity I have set the encoder scale to -1 : setp encoder.0.position-scale -1 to see what happens. Reasoning that the voltage should increase instead of decrease when the torch lifts up. I am no expert on HAL, but I assumed that's how I could reverse the voltage scale. It didn't make any difference though. I can clearly see the torch lifting up substantially before there is a drop in the voltage, and it gets worse from there.

Please Log in or Create an account to join the conversation.

More
21 Dec 2021 03:34 #229599 by CFE
Replied by CFE on topic Voltage Scale and Auto Volts
Hi all,

I will let it rest till after New Year. Just cut 1.6mm at 45A, 6000mm/min and the THC works fabulously. I got a spare THCAD-10 here which I will use when I get to it, there is something in the voltage reading on the thick material that is bugging me.

Thanks for all your help and suggestions again, I know this is all a work of love and understand the time and effort that goes into a piece of software like this. Much appreciated !

Cheers, Peter

Please Log in or Create an account to join the conversation.

More
21 Dec 2021 03:35 #229600 by phillc54
The plasmac component uses the absolute value so changing the sign will have no effect.

 There is a hal pin name plasmac.target-volts that may be worth watching, that shows the voltage that THC is trying to maintain.

Please Log in or Create an account to join the conversation.

Moderators: snowgoer540
Time to create page: 0.141 seconds
Powered by Kunena Forum