LinuxCNC, Plasma, THC questions

tommylight wrote: ........................ from what i remember, there is a setting in mach for setting the reaction speed in regards to the maximum speed and acceleration set for Z axis, and it is in percent. I do not recall the exact naming, but it is there.

Thanks for the response Tom

In Mach3 there is a setting for THC Z axis speed. It is expressed as a percentage of max velocity (or rapid speed) as set in motor tuning.

However the THC up/down move does most certainly NOT include an acceleration ramp. Let me be clear, this is via the LPT driver.

I have no certain knowledge of how external pulse generators like SoomthStepper , for example, handle THC Z axis moves. Although I believe it is the same.

So my question remains, does LinuxCNC make THC Z axis moves the same as Mach3 or does it include an acceleration ramp?

Greolt wrote: So my question remains, does LinuxCNC make THC Z axis moves the same as Mach3 or does it include an acceleration ramp?

The LinuxCNC step-generator has a built-in acceleration limit that you can configure.

There are other options too. But I would start off by simply setting the stepgen accel limit to a suitable value.

andypugh wrote: The LinuxCNC step-generator has a built-in acceleration limit that you can configure.

So does Mach3. Exactly that.

I really don't wish to sound rude or arrogant. Please forgive me if I do. But that does not answer my question.

Sure seems like it answers the question

Thats is if you set the acceleration limits of the stepgen
those limits will be obeyed regardless of where the stepgen
position or velocity command comes from, be it axis position, THC position, THC velocity, phase of the moon, or whatever

Greolt wrote: I really don't wish to sound rude or arrogant. Please forgive me if I do. But that does not answer my question.

If that doesn't answer your question, then I have misunderstood the question.

Can you re-phrase the question in a manner that makes it clear why my answer is not an answer?

(There are many other options, such as limit2 and pid, but for a THC I actually think that setting stepgen accel and velocity limits is sufficient and adequate)

PCW wrote: Sure seems like it answers the question

Thats is if you set the acceleration limits of the stepgen
those limits will be obeyed regardless of where the stepgen
position or velocity command comes from, be it axis position, THC position, THC velocity, phase of the moon, or whatever

"those limits will be obeyed regardless of where the stepgen
position or velocity command comes from"

OK I will take that as a yes.

Thanks very much.