Torch On HAL Pin when using 7i76e

snowgoer540 wrote:

I am not quite sure about ohmic, but ohmic3 uses the hal enable pin as a check for whether or not the output is true.

In other words, if the voltage > threshold, and NO ohmic enable input, there is no output from the component.

So you need to provide the enable whether or not you plan to use a relay. I thought this was documented in the hypertherm thread. Maybe it was somewhere else. Either way Rod's guided several people on here through the use of his ohmic3 component. I would seek out one of those threads if it's not in the hypersensing thread I linked earlier.

snowgoer540 wrote:

txtrone wrote:

Ok, also... do I need some sort of custom firmware from Mesa to make hypersense work with the 7i76e?

If you also have a THCAD for THC, then yes.

ohmicsense.ohmic-on

man ohmic

net ohmic-true ohmicsense.ohmic-on => plasmac.ohmic-probe

setp ohmicsense.threshold 22
setp ohmicsense.ohmic-low 1

ohmicsense.ohmic-volts

txtrone wrote:

snowgoer540 wrote:

txtrone wrote:

Ok, also... do I need some sort of custom firmware from Mesa to make hypersense work with the 7i76e?

If you also have a THCAD for THC, then yes.

Where can I find the instructions on the mesa driver installation that I would need?

rodw wrote:

Ok, because you are using a downdraft table and don't have to contend with water splashing around, the best course of action is to use the original ohmic.comp that is part of the Linuxcnc deployment from 2.8 and up.

You have no need for all the fancy crap Ohmic3 does to try and work around the water table problems where the voltage drop can be less than 1 volt between the probe on and off.

The correct pin name for ohmic sense probing is

ohmicsense.ohmic-on

The documentation is here linuxcnc.org/docs/devel/html/man/man9/ohmic.9.html
or available if you type

man ohmic

The suggested connections in your machine.hal file are shown in the documents. Note that on a new installation, the last line

net ohmic-true ohmicsense.ohmic-on => plasmac.ohmic-probe

will be added from pncconf or the Plasmac configurator so it should be omitted

These pins control the voltage threshold:

setp ohmicsense.threshold 22
setp ohmicsense.ohmic-low 1

In this example, the probe comes on when the voltage is > 22 volts and goes off when its < 1 volt.

I would jog the torch down so it touches the material and use halshow to review the voltage on this pin

ohmicsense.ohmic-volts

before setting the upper threshold. On my system I always get 24 volts so a threshold of 22 works for me but you may wish to set it lower (18v maybe?)

And yes the relay to turn the AC side off is optional. I think I have bypassed the relay.

The only reason to turn the power off is becasue there have been some suggestions of the possibility of electrolytic corrosion inside the torch tip on water tables (water shorting out the internal contacts) when machines that are left powered on while idle for long periods. But because you have a dry table, this will not be an issue for you.

So in your case, keep it simple, leave the relay out and just turn the power supply on when you power up the machine!

rodw wrote:

On the mesa product page, there is a zip file that includes lots of bit files for different configs. the one to use ends with pl.bit (where pl = plasma)

You need to use mesaflash to burn this to the 7i76e
I do show how to do this in my video

rodw wrote:

Ok, because you are using a downdraft table and don't have to contend with water splashing around, the best course of action is to use the original ohmic.comp that is part of the Linuxcnc deployment from 2.8 and up.

You have no need for all the fancy crap Ohmic3 does to try and work around the water table problems where the voltage drop can be less than 1 volt between the probe on and off.

The correct pin name for ohmic sense probing is

ohmicsense.ohmic-on

The documentation is here linuxcnc.org/docs/devel/html/man/man9/ohmic.9.html
or available if you type

man ohmic

The suggested connections in your machine.hal file are shown in the documents. Note that on a new installation, the last line

net ohmic-true ohmicsense.ohmic-on => plasmac.ohmic-probe

will be added from pncconf or the Plasmac configurator so it should be omitted

These pins control the voltage threshold:

setp ohmicsense.threshold 22
setp ohmicsense.ohmic-low 1

In this example, the probe comes on when the voltage is > 22 volts and goes off when its < 1 volt.

I would jog the torch down so it touches the material and use halshow to review the voltage on this pin

ohmicsense.ohmic-volts

before setting the upper threshold. On my system I always get 24 volts so a threshold of 22 works for me but you may wish to set it lower (18v maybe?)

And yes the relay to turn the AC side off is optional. I think I have bypassed the relay.

The only reason to turn the power off is becasue there have been some suggestions of the possibility of electrolytic corrosion inside the torch tip on water tables (water shorting out the internal contacts) when machines that are left powered on while idle for long periods. But because you have a dry table, this will not be an issue for you.

So in your case, keep it simple, leave the relay out and just turn the power supply on when you power up the machine!