Shielded Cables

[5-0coyote]

I have a few questions about ground and drains for shielded cables for my plasma and later router I will attach picture

The din rail with the green/yellow ground blocks attached to it is where I have my drains from the shielded cables landed. Drains are attached on both sides of the din rail. I believe this ok being the clamp on green/yellow blocks have metal clamps and basically turned the whole din rail into ground bar.

Also if the above is ok, being the din rail is screwed to the back plate would that mean that the whole back plate is a ground bar and drains could be landed anywhere on the back plate without creating ground loops?

The blue terminal block is where I have landed my cpc cable from my Hypertherm two of the wires from the cpc are ran over to the relay for torch fire. My plan is to come back out of the encloser with dc power and 50:1 divider voltage to THC. THC up, down, arc ok back into the cabinet to inputs. Does anybody have pictures of how the resistors are connected for inputs. I am having trouble understanding how they are put in and why. Is it because device like proms has to much voltage for input. Again I just really don t understand resistors and how they work.

Don t beat me up too bad on the wiring, I plan to clean it up some before I m done.

 

[breezy]

@5-0coyote

Hi Coyote

Don t beat me up too bad on the wiring, I plan to clean it up some before I m done

Your wiring is better than what I did when I was at the same stage that you are at now.

being the din rail is screwed to the back plate would that mean that the whole back plate is a ground bar and drains could be landed anywhere on the back plate without creating ground loops?

That's correct, but as you have lots of spare ground din terminals I would use them. What you don't want to do is connect another ground "source" to the other end of your shields/drains, that will cause ground loops.

I am having trouble understanding how they are put in and why. Is it because device like proms has to much voltage for input. Again I just really don t understand resistors and how they work.

As their name suggests they resist the flow of electrons. So using Ohm's law V=I x R, voltage dropped across a resistor equals the current flowing through the resistor multiplied by the resistance. This can be rearranged to I = V/R, the current flowing through a resistor is proportional to the voltage divided by the resistance.

So generally resistors are used to limit current flow. The MASSO inputs are opto coupled and need a +ve signal to operate, the resistor is used to pull up the input to +ve voltage when the input is "open/floating" for ground switching inputs. Without a resistor, supplying +ve voltage to a input that switches to ground would short out the PS, so usually 5.6K resistor is placed in the supply lead and this limits the current to 4.3mA on a 24v supply, when the input triggers.

50:1 divider voltage to THC

This is the other use of resistors. Two resistors with a ratio of 50 to 1 in resistance value are placed in series and tapped in the middle to read the voltage across lower value one.

Hope this helps to explain the usage of resistors.

Regards,

Arie.

PS. A first name signature helps in answering inquires, unless you like being called Coyote!

 

[5-0coyote]

Thank You, Arie for taking the time to answer.

In studying the diagram that Ross posted I believe he was using raw voltage from the plasma to the THC, my Hypertherm has the 50:1 divider board built in will it still need resistors?

Thanks for the help

Curt

 

[breezy]

@5-0coyote

my Hypertherm has the 50:1 divider board built in will it still need resistors?

Curt,

I'm assuming you are using a Proma THC, are you referring to the signals out of the THC, then yes the resistors are required. The only change to Ross' connection is where you connect the output from the Hypertherm to the THC, follow the diagram on the MASSO documentation for the Proma Compact THC 150.

Regards,

Arie.

 

[5-0coyote]

Arie,

Once again Thank You for your help. I m not sure if I will be using the Proma but it seems to be the only one that has had success.

I have seen you post a lot of good info here on the forum and you seem to be pretty darn smart with this stuff. Do you believe the the price unit or one of the other up and down THC will work just like the Proma? I have seen in posts saying any up and down THC will work but never any success stories. It would be nice to get a price to work. I still have about a month before my table will be ready but would like to be ready to go when it is.

Thanks again Sir for your help

Curt

 

[breezy]

@5-0coyote

Curt,

Do you believe the the price unit or one of the other up and down THC will work just like the Proma?

I was trained as a Telecommunication Technician (40 years ago) who progressed into computers and software, so I can answer questions about electronics and Gcode programming, but in regards to Price THC over Proma THC, I can't give answer on that. Until recently I didn't know that THCs existed, all I knew about plasma was they needed clean dry air and made lots of sparks. So in this case we need others to answer.

I have seen in posts saying any up and down THC will work but never any success stories. It would be nice to get a price to work.

And those that asked for help here, have not responded to requests on how they solved their problem.

Ian in this thread has come up with another way to control torch height. THC highjacked from Masso.

Regards,

Arie.

 

[Ross]

Here is a couple of links to look at.

From Ross.

Search results for query: masso-plasma-proma-thc-150-correct-wiring/

www.masso.com.au