From steps/s to mm/s speed conversion

[Loni]

Hello everyone

I am working with a phidget controller model 1067, together with a stepper motor that has a step angle of 1.8 degrees. The motor doesn't have a gearbox. It is attached to a ball screw.
When the motor does 1 rotation, the distance performed by the block attached is 3.6mm.

Could you please provide a bit of support on how to translate the speed units shown in the program as 100 steps/s to mm/s units?

I thank you for your time and hope for your understanding.

Kind Regards

[mparadis]

"Position" in our libraries is measured in microsteps, which are 1/16th of a step. You can figure out the conversion with unit analysis:

Code: Select all

1 step     16 microstep        360°
______  x  ____________   x  ________   =  3200 microsteps/rotation
 1.8°         1 step        1 rotation

Then, if your ball screw moves 3.6mm per rotation,

Code: Select all

3200 microsteps        1 rotation
_______________   x   _____________ = 888.889 microsteps/mm
  rotation              3.6mm

So if you set your target position to 889, the ball screw should move 1mm.
If your "3.6mm" number was determined experimentally, you may want to use the actual gear ratio of the ball screw to get a more accurate conversion.

[Loni]

Hello mparadis

Many thanks for your reply.

Actually, I have a DBX1204-100 type linear actuator, and a stepper motor model 42BYGH48. I have checked the linear actuator, but I can't find the actual gear ratio of the ball screw.

Perhaps from your experience, do you know what would be the most typical gear ratio for this type of actuator.

Many thanks

[mparadis]

Sorry, I don't know what the gear ratio would be.

Another way you can improve the accuracy of your conversion is by measuring the distance of the actuator at multiple positions. So if you record the distance at position 1000, 2000, 3000, etc.. and plot a bunch of points on a graph in excel or google sheets, you can take the line of best fit and then use the equation of that line to convert any position value to a displacement.

[Loni]

Thank you for your reply.
I might need to open the old recipes and see if I can contact the manufacturer of it.

Have a nice day.