Hi dchapman,
Please see other Threads on noise/jitter issues with these capacitive encoders.Planned encoders: CUI AMT 102-V
Step/Dir to Gecko. Gecko closes the position loop. Open loop from the Controllers perspective. I would not refer to it as "KFLOP performing path following". Rather KFLOP is creating the trajectory.Option 1: KMotionCNC->KFLOP->Gecko G320x->brushed servo with quadrature encoder.
Case 1.1. Quadrature encoder connected to Gecko G320x. As I understand it, when the encoders are connected to the G320x, the G320x does closed loop control for each step commanded (allowing up to a configured "count following error" before declaring a fault). In this case, is the KFLOP performing path following in open loop mode (ie. no PID control) expecting that the G320x will keep up?
This doesn't work. The C320X requires encoder feedback to close the position loop.Case 1.2. Quadrature Encoder connected directly to the KFLOP. Does this work? or does the G320x require encoders connected? If it does work, would it allow the KFLOP to "close the loop" during it's path following operations?
SnapAmp is simply an IO device for KFLOP. It has differential encoder inputs so the encoder position can be presented to KFLOP and it allows KFLOP to command a Motor Current. Motor Current basically corresponds to motor torque or acceleration.Option 2: KMotionCNC->KFLOP -> SnapAmp -> brushed servo with quadrature encoder
Case 2.1. Quadrature encoder connected to SnapAmp. When the encoders are connected to the SnapAmp, does the SnapAmp perform closed loop control for each step commanded (like the GeckoDrive 320x does)?
Whether the encoder feedback is connected directly to KFLOP or to SnapAmp doesn't make any difference to the functionality. In both cases the position is available to KFLOP to close the loop, plot the response, monitor following errors, and so forth. The difference is that KFLOP has only single ended inputs and SnapAmp has differential inputs. Differential inputs have less noise sensitivity. When you purchase encoders its best to get differential outputs as they can be connected to either differential inputs or single ended inputs.Case 2.2. Quadrature Encoder connected directly to the KFLOP (as shown in Dynomotion's "KFLOP+SnapAmp DC Brush Motors with MPG" wiring diagram). Does the KFLOP "close the loop" during it's path generation/following operations or is it operating in a similar way to Case 1.1 above where the Gecko is closing the loop for each step command? Is there any benefit in path following capability by using the SnapAmp versus the G320x?
In this configuration there is no need for "steps" or to send the commanded position anywhere. KFLOP performs the trajectory and knows the desired position with floating point precision. The advantage with SnapAmp would be this elimination of steps and the ability to tune and verify the system's performance using the KMotion.exe parameters and tools. Another advantage with KFLOP closing the loop is that KFLOP can track encoder position while the Axes are disabled or have faulted. The allows recovery without loss of position and having to re-home the system.
I've heard good things about PoKeys but not familiar with it. KFLOP only supports Mach3 not Mach4. When using Mach3 or Mach4 you will be using the Trajectory Planner in Mach3 or Mach4. We feel the KMotionCNC Trajectory Planner performs better on complex high-performance jobs.Option 3: Mach -> KFLOP ...
Case 3.1 I understand that Mach is doing the path planning but in open loop mode. In this case what is the advantage of using KFLOP versus PoKey57CNC?
HTH
Regards