Servo Tuning detailed How To.
superlen wrote: The drives are configurable so I can configure them for velocity or torque mode and let Linuxcnc do the tuning if necessary. I take it that is the most common way of configuring Linuxcnc (with it handling motion control). I keep thinking that the motion control should be outside the PC in embedded hardware, but I realize that with the power of Linux & RTOS this isn't as prevalent as it once was, particularly with a FPGA doing some of the heavy lifting in between.
The most common setup is a velocity-controlled servo drive (velocity loop in the drive, an tuned in the drive) and a position loop in LinuxCNC (tuned after the velocity loop is tuned)
The fundamental point of EMC (which became LinuxCNC) was to be a motion controller that ran on commodity PC hardware rather than on specialised hardware. Whereas Mach3 had commercial reasons to support external motion cards like the Smoothstepper, LinuxCNC has no such commercial incentives, so the philosophy is that LinuxCNC is a motion controllerm and if you don't want it to do that, then use something else. But I digress.
after studying the current setup in more detail, they aren't. They are receiving an analog voltage from a PCI motion card (similar to Mesa, but not supported by Linux CNC),
Are you sure? What card is it?
Thanks for the information on the velocity loop vs. position loop.
The drives are KollMorgen ServoStarCDs. The PCI card is an Acroloop 8020. With the reasonable price of the Mesa Cards it was way more obvious to just purchase and play, rather than write a driver. The Mesa ethernet version(s) simplifies some wiring for me as well.
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