Stepper motor feedback controller able to dynamically check the positioning of the shaft and prevent any step loss in 3D printing, CNC, etc. It mounts directly on NEMA17 motors.

All management of the controller is entrusted to Microchip's programmed PIC32MX250F256HI / PT microcontroller; while the DRV8843 driver from Texas Instrument, driven directly by PWM pulses, allows stepper motor control even with very dense microstepping. The AM4096 magnetic encoder, equipped with a resolution of 12 bits (4096 steps / revolution), is able to detect the position of the motor shaft and transmit it to the controller.

You can control it through USB interface, I2C port or SPI port.

Furthermore, having the classic EN / DIR / STEP inputs typical of traditional controllers, you can replace your driver with MotorFish.

There is also a reset button, status LED, 4-pole terminal block for the two motor windings and a terminal block for the power supply (8.5 and 45 VDC).

Dimensions (mm): 42.2x42.2x12, weight: 12.5 grams.

Open loop control:
the controller sends a command to the motor without confirmation of the actual movement; if for any reason the motor was unable to move (for example if the print head encountered an obstacle or if the required travel speed is too high) the error is maintained and accumulates with any other subsequent errors .

Closed loop control:
a movement command is given to the motor, but in this case a position sensor on the same is able to provide a "confirmation" of the movement that has taken place or an error signal if this is impossible. The controller can then decide whether to stop everything, try again or go ahead trying to correct the problem later.
This type of control has several advantages over closed-loop control; first of all, the movement no longer depends on the type of motor, but only on the resolution of the motion sensor (an encoder, usually). So we will no longer be obliged to work in discrete steps (step) or microsteps (microstep) but we will be able to have continuous engine operation, with less mechanical vibrations.
Not being at risk of losing position, we can "push" the engine to the maximum without worrying about anything or almost anything; if the engine is unable to follow the commands, the electronics will notice it and be able to remedy it, both by reducing speed and / or acceleration and by correcting errors.
Another advantage is the reduced power consumption. In fact, in an open cycle stepper motor we are obliged to maintain a high current in the windings even with the motor stopped, to avoid unwanted movements perhaps due to rapidly decelerating masses or involuntary tampering with the printer plate; in the closed cycle motor, when it is not in motion, we can reduce the current in the windings to zero, confident that in case of involuntary movements the electronics will be able to immediately correct the position.

• Closed loop control of speed or position
• Various control interfaces:
  • USB for direct connection to PC
  • I²C for use with a microcontroller
  • SPI
  • EN / DIR / STEP inputs typical of traditional controllers, which make it possible to replace them directly with MotorFish
  • Acceleration and deceleration limitation
• Maximum microstepping on a motor with 200 steps is equal to 4096/200 = 20.48 microsteps / step.
• All available I / O are programmable by software, so nothing prevents you from using them for anything else. MotorFish is programmed exactly like an Arduino (or, more precisely, like a Fishino32), with all the necessary possibilities.

• Datasheet PIC32MX250F256HI/PT
• Datasheet DRV8843
• Datasheet AM4096