How does an A4988 work?

How does an A4988 work?

The A4988 driver allows microstepping by allowing intermediate step locations. This is achieved by energizing the coils with intermediate current levels. For example, if you choose to drive NEMA 17 having 1.8° or 200 steps per revolution in quarter-step mode, the motor will give 800 microsteps per revolution.

Do stepper motors need capacitors?

Slo-Syn manual on a stepper motor ran as an AC synchronous motor shows a resistor required in series with the cap. The required value should result in a phase shift of 90° between the winding pair. For unknown motors, they recommend using a resistor & capacitor substitution boxes in order to achieve max.

Why decoupling capacitors are used?

If the input voltage drops, then a decoupling capacitor will be able to provide enough power to an IC to keep the voltage stable. If the voltage increases, then a decoupling capacitor will be able to absorb the excess energy trying to flow through to the IC, which again keeps the voltage stable.

How do I reset my A4988?

The RESET pin is floating on the breakout (not pulled high or low), you can simply connect this to the SLEEP pin if you want, otherwise you will want to (so it will be pulled high also), or control it as you wish. The ENABLE pin is pulled low on the breakout, this pin is active low, so by default the board IS enabled.

What is the output capacity of the a4988 stepper motor driver?

A4988 Pinout click on image to enlarge The A4988 is a complete Microstepping Motor Driver with built-in translator for easy operation. The driver has a maximum output capacity of 35 V and ± 2 A.

What’s the maximum current rating of the a4988 driver?

The A4988 driver IC has a maximum current rating of 2 A per coil, but without a heat sink it can only supply about 1 A per coil before it starts to overheat. The driver usually comes with a small adhesive-backed heat sink, which I recommend you to install right away.

What is maximum voltage for Pololu a4988 stepper?

Under the right conditions, these spikes can exceed the 35 V maximum voltage rating for the A4988 and permanently damage the board, even when the motor supply voltage is as low as 12 V.

What kind of capacitor do you need for a stepper driver?

One way to protect the driver from such spikes is to put a large (at least 47 µF) electrolytic capacitor across motor power (VMOT) and ground somewhere close to the board. Four, six, and eight-wire stepper motors can be driven by the A4988 if they are properly connected; a FAQ answer explains the proper wirings in detail.