Fueler1 wrote:. I can add the braking resistor and board Automation recommended.
. The only unclear point is whether the Automation board allows control of spindle orientation via it's rpm feature.
. Perhaps can do spindle orientation with the rpm feature and the rest is PLC work or some other coding?
. Yes, I don't understand yet what is supposed to do what.
. Clear it up for me please on how this orientation is accomplished.
I think if you look on the back wall of the cabinet, partly hidden behind your GS3 spindle drive, you will see that you already have a braking resistor installed.
How is orientation accomplished?
Usually, it is handled by specialized software in the spindle drive (VFD). That is why the usual recommendation is to purchase a drive that specifically features orientation capability in the software. As Marty points out, the Delta C2000 is one such drive. The GS3 is not.
Given a drive with orientation capability in its software:
- The CNC control's PLC sends an "Orient" command signal to the spindle drive.
- The CNC control then sits and waits for an "Orient Complete" signal back from the spindle drive.
- The spindle drive rotates the motor as needed to locate the encoder's index pulse; then rotates it an additional number of counts set in a parameter (to get around to a chosen orient position that is not necessarily at the index pulse); then stops there, and continues to apply current as needed to hold the motor shaft at that location. The spindle drive then closes the "orient complete" signal to the PLC.
At this point the spindle drive is running closed-loop position control, much like what your Centroid control does with the X, Y and Z axes: if you do anything to push the spindle away from the orient position, the drive will see this on the encoder, and will apply more and different current to the windings, to push it back where it needs to be.
As an alternative, given a spindle drive that does not have its own orientation software, but which (1) does reliably control speed all the way down to zero (rather than shutting off current below some non-zero minimum frequency), and which (2) accepts a bipolar analog signal to control speed and direction (so that the PLC can reverse the spindle simply by making the analog speed command voltage go negative, instead of by switching relays), then it is possible to write orientation software into the Centroid PLC program.
However, I would be surprised if the GS3 had reliable speed control ability all the way down to, and past, zero, even with an encoder card installed. You could try contacting Automation Direct to ask about that, though.