sorry there are some words missing. This is what I meant to say. The general consensus is that you dont use servos on the Z axis of a plasma.
On 2015-01-12 16:22, Marius Liebenberg wrote: > Short reply is - the THCUD does not work for servo loops but is designed > for stepper systems. > You will have to look at rolling your own control and for servos that > might take some doing. > The general consensus is that you dont use servos on the Z axis of a plasma. > Most systems use a > standalone THC system that drives the Z axis independently of the motion > controller. Most of them use a stepper or a dc motor with position feedback. > > I am sure that you could put together a system that uses a PID loop in > linuxcnc and use that to control the THC function. > > On 2015-01-12 13:49, lloyd wilson wrote: >> We are trying to adapt our Techno router (servo, not stepper) to use a >> plasma torch & I'm having some difficulty understanding how to utilize >> the thcud hal component. Conceptually, it seems simple: the component >> sits between the axis and pid modules of the z axis and adds a >> correction to the commanded z height as dictated by the torch height >> controller. I've plumbed the thcud component into the system config >> files and built a simulator to mimic the thc box (up, down, & arc OK >> inputs). All the IO appears to be working properly, but I see no altered >> Z heights when exercising the inputs. >> >> Some questions from reading the component documentation & source: >> >> - the thcud component generates a position feedback value to be fed back >> to the motion component, but the 'normal' servo configuration sends >> position data from the encoder function to both the pid component and >> the motion component. What is the consequence of decoupling the two >> feedback inputs? >> >> - in the code, I don't see where either of the parameters (velocity_tol >> and correction_vel) are initialized. >> Is that somehow done behind the scenes? Or does it need to be done in >> the hal files? >> >> - Also, why is the velocity tolerance divided by 100 in the code? As I >> read the man page, the pyvcp spin box value should associate with the >> tolerance parameter, but the spin box input is already limited to a max >> of 1 - looks like it's taking a percentage of a percentage. >> >> At a more expedient level, can someone point me to a functional >> servo-based configuration that uses the thcud component? >> >> As always, upfront thanks for the help >> >> -ldw >> >> ------------------------------------------------------------------------------ >> New Year. New Location. New Benefits. New Data Center in Ashburn, VA. >> GigeNET is offering a free month of service with a new server in Ashburn. >> Choose from 2 high performing configs, both with 100TB of bandwidth. >> Higher redundancy.Lower latency.Increased capacity.Completely compliant. >> vanity: www.gigenet.com >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users >> -- Regards /Groete Marius D. Liebenberg +27 82 698 3251 +27 12 743 6064 QQ 1767394877 ------------------------------------------------------------------------------ New Year. New Location. New Benefits. New Data Center in Ashburn, VA. GigeNET is offering a free month of service with a new server in Ashburn. Choose from 2 high performing configs, both with 100TB of bandwidth. Higher redundancy.Lower latency.Increased capacity.Completely compliant. vanity: www.gigenet.com _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
