[Bobbyr70]

Is there anyone that has set up and using an ohmic sensor with plasma cutting? I have one I purchased from a guy in Turkey and I don't know enough about the wiring on the breakout board to get it to work.
What I have so far is: power to the sensor. I have the wiring connected to the breakout board for up and down. I have messed around with mach3 settings a bit but still have questions about the proper arrangement and also what post processor I would use to make it work. I also have a thc300 but it wont stop diving around corners. Any help would be greatly appreciated, Thanks.

[jimcolt]

Ohmic sensing is simply sensing electrical contact between the shield (front most part of a Hypertherm plasma torch) and the plate. This is used to determine where the surface of the plate is located before each cut cycle.....so that the z axis electronics can retaract the torch to the recommended pierce height before firing the torch. On some torch height controls it is also used during cutting or traversing to detact collisions with the plate....to stop motion or to force the z axis to retract to counteract the collision.

To make it work you need the proper plasma torch and retaing cap that has a wire connection for the shield.

Diving in corners is caused by the machine having to deaccelerate....which causes the arc voltage to increase....which causes the arc voltage based height control to move closer to the plate to correct the voltage. You can minimize this diving by increasing the acceleration rate to the point that the diving is minimized, although the best fix is to use the software to monitor the speed .....and when the cut speed gets to 80% of the programmed value..the z axis should freeze.


Jim Colt Hypertherm