Dynomotion Forum

Hi everyone
I'm thinking about buying the Kflop controller for my system. I need to use linear encoder on stepper motor system for closed loop operation (because I need to have really small tollerancies on my system, about 1 um) on a Optimum bf20 machine (modified, with c3 ballscrews and precision linear guides). Is it possible? Do you know where I can find any kind of tutorial or example or something that may be usefull? I red something and I saw that Kflop only support linear encoder with TTL output so I'm going to buy one soon. Is there any other kind of hardware I may need?
I'm not sure if this is the right section so, if not, feel free to move the topic.

Thank you in advance.

Hi MattiaGrassi93,

1um is of course extremely difficult to achieve. Linear Scales only correct for some mechanical errors. Is speed also important?

What type of Stepper Drivers are you using?

Try to get encoders with differential outputs. Differential outputs can be connected to differential inputs or single ended inputs. See here for more info.

Here is an article on closed loop Step/Dir mode. Note the example is using rotary encoder feedback but linear scale encoder feedback is similar just with more mechanics in the control loop.

Good afternoon Tom. Can i connect to Kflop rulers with that output? thanks

Hi Igor,

Yes you can connect that differential encoder to KFLOP's single ended encoder inputs by leaving the complementary signals disconnected. However there will be higher noise susceptibility than if you use differential to single ended converters. See also this.

Thank you for answering so quickly. I looked... also there were questions. Can you give me an example of such a connection?

Hi Igor,

You would need to wire the encoder to a KFLOP encoder input.

The Output Mode would be CL Step not CL Micro. Microstepper Amplitude would not apply as your drives control the current. See here.

Don't concern your self with a C Program at this time. Use the KMotion Screens.

I do not understand how to connect pins A, A +, B, B+

Hi Igor,

As I said before to connect differential encoders with A+ A- B+ B- to single ended inputs with only A and B, just connect one of the A and one of the B and leave the other two signals unconnected. Note this will be more susceptible to noise than a differential input that uses all 4 signals.

good afternoon Tom. I 'm getting a mistake. Connected the ruler to pin7-8, often the axis to become yellow is the reason and how to eliminate it. After reloading, the position is inadvertently counted. thanks

Hi Igor,

For us to help you would need to tell us exactly how things are configured and what you are doing.

You should get everything configured, tuned, and tested in KMotion.exe before attempting to use KMotionCNC.

I suspect your Axis Resolutions in KMotionCNC | Tool Setup | Trajectory Planner | Axis Parameters is not set properly. If they are set at zero then trying to use them to convert from counts to GCode units will result in a division by zero. See also here and here.