THCAD-300 and Plasmac User Guide questions
- snowgoer540
- Topic Author
- Away
- Moderator
- Posts: 2140
- Thank you received: 687
I recently converted a working gmoccapy install to Plasmac, and I am trying to get things right for my THCAD-300. It seems the Plasmac userguide specifically shows examples for the -10, and I am having some trouble getting numbers that make sense for the -300. I am in fact using F/32 as a jumper setting.
0V = 120 kHz
300V = 920.4 kHz
Under 22.1, the divider ratio for the THCAD-300 is said to be 29. I am wondering where this came from? I am guessing it is a known value from Mesa?
For 22.2, the example shown is for a 10v board. Being that mine is a 300v board, is the new formula simply Divider_Ratio/((300v_frequency-0vfrequency)/32/300)? When I plug in my numbers I get 29/((920400-120000)/32/300) = 0.347826. This leaves my display on Plasmac bouncing around between 5-8 volts. It seems like I am missing something simple here? But maybe I made incorrect assumptions when using the 10v formula for the 300v board.
Lastly, for 22.3, there's a new line since the last time I looked at the documentation:
setp hm2_7i96.0.encoder.00.filter 1
I am assuming that this just turns on the low pass filter as specified in section 4.11? Which also makes me assume that you need to add the line: setp plasmac.lowpass-frequency 100 to the HAL file as well? I am not quite sure I follow what this is useful for? Where did 100 kHz come from?
Thanks in advance for the help!
-Greg
Please Log in or Create an account to join the conversation.
- tommylight
- Online
- Moderator
- Posts: 15159
- Thank you received: 5059
That is all, as 29 multiplied by 4 to 5 you are getting will give 116 to 145.
Please Log in or Create an account to join the conversation.
forum.linuxcnc.org/plasma-laser/32585-scalethcad-component
I still use this today and set plasmac to have a scale of 1 and an offset of zero but I have dropped the included filter.
I think your offset = 120000/32 = 3750
So your full scale = 920400/32 = 28762.5
So your range from 0v to 300v = 28762.5 - 3750 = 25012.5
So your scale (frequency count per volt) 25012.5/300 = 83.375
So enter 3750 and 83.375 in plasmac and see how you go.
Please Log in or Create an account to join the conversation.
- snowgoer540
- Topic Author
- Away
- Moderator
- Posts: 2140
- Thank you received: 687
You do not have a divider so do not use the 29.
That is all, as 29 multiplied by 4 to 5 you are getting will give 116 to 145.
That makes sense. Sounds like the voltage divider should actually just be 1 then.
But I am curious, why does the user guide say that it is 29?
Please Log in or Create an account to join the conversation.
- snowgoer540
- Topic Author
- Away
- Moderator
- Posts: 2140
- Thank you received: 687
I've never really agreed with the idea that you need to do some maths to configure a piece of software. I really found this confusing when I started and thats why I wrote this component that lets you enter all of the parameters and no need to do any maths
forum.linuxcnc.org/plasma-laser/32585-scalethcad-component
I still use this today and set plasmac to have a scale of 1 and an offset of zero but I have dropped the included filter.
I think your offset = 120000/32 = 3750
So your full scale = 920400/32 = 28762.5
So your range from 0v to 300v = 28762.5 - 3750 = 25012.5
So your scale (frequency count per volt) 25012.5/300 = 83.375
So enter 3750 and 83.375 in plasmac and see how you go.
I will definitely have to check that component out, I didnt know it existed. I thought to myself "why cant my frequencies and which THCAD I have just be part of the configuration?". I am sure there are lots of other things on the priority list though.
I think the scale is looking for a really small number though. Everything you said makes it more clear, but I'm thinking it's looking for a really small number for scale though, would it be (1/83.375) = scale (0.011994)?
So you said you dropped the filter. Why? I'm still not sure I understand what the filter is supposed to do exactly.
Lastly, someone recently brought the hypersensing to my attention. Guess I have to order another THCAD now LOL. Good work there!
Please Log in or Create an account to join the conversation.
I think you need one of these:I think the scale is looking for a really small number though. Everything you said makes it more clear, but I'm thinking it's looking for a really small number for scale though, would it be (1/83.375) = scale (0.011994)?
- 29/((920400−120000)/32/10) = 0.01159420289855072464
- 1/((920400−120000)/32/300) = 0.01199400299850074963
Because then it would lock PlasmaC into one hardware vendor.I will definitely have to check that component out, I didnt know it existed. I thought to myself "why cant my frequencies and which THCAD I have just be part of the configuration?". I am sure there are lots of other things on the priority list though.
No, this not the lowpass filter, it is a filter in the encoder. From memory that was recommended by PCWI am assuming that this just turns on the low pass filter as specified in section 4.11
Edit: forum.linuxcnc.org/27-driver-boards/3659...hcad?start=30#135396
Please Log in or Create an account to join the conversation.
- snowgoer540
- Topic Author
- Away
- Moderator
- Posts: 2140
- Thank you received: 687
Good point on locking Plasmac to one vendor, didnt think of that.
Thanks for the reply, it helps a lot!
Please Log in or Create an account to join the conversation.
jscalc.io/calc/NTr5QDX6WgMThBVb
[EDIT]
Reference post forum.linuxcnc.org/plasma-laser/35449-an...ent?start=910#135473
Please Log in or Create an account to join the conversation.
Please Log in or Create an account to join the conversation.
- snowgoer540
- Topic Author
- Away
- Moderator
- Posts: 2140
- Thank you received: 687
I made a little calculator for this a while ago
jscalc.io/calc/NTr5QDX6WgMThBVb
AWESOME! Thank you so much!
If those numbers are confirmed can I put a link to that in the PlasmaC docs.
This works out to what I ended up calculating. My machine has no voltage divider, so 1 makes sense there.
Please Log in or Create an account to join the conversation.