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Stepper Motor Driver A4988 (HCMODU0068) 
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Post Stepper Motor Driver A4988 (HCMODU0068)
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This module is based upon the Allegro A4988 stepper motor driver and is ideal for use in 3D printer, CNC, and other applications where precise control of a stepper motor is required. Its pinnout is compatible with the StepStick design. This module can be used on its own (controlled by a microcontroller), or used with a RepRap compatible RAMPS shields such as our item number HC3DPR0002. .

The A4988 is a complete microstepping motor driver with built-in translator for easy operation. It is designed to operate
bipolar stepper motors in full-, half-, quarter-, eighth-, and sixteenth-step modes, with an output drive capacity of up to
35 V and ±1 A (Although the A4988 device is rated to 2A, this module has a maximum current of 1A). The A4988 includes a fixed off-time current regulator which has the ability to operate in Slow or Mixed decay modes. The translator is the key to the easy implementation of the A4988. Simply inputting one pulse on the STEP input drives
the motor one microstep. There are no phase sequence tables, high frequency control lines, or complex interfaces to program. The A4988 interface is an ideal fit for applications where a complex microprocessor is unavailable or is overburdened. During stepping operation, the chopping control in the A4988 automatically selects the current decay mode, Slow or Mixed. In Mixed decay mode, the device is set initially to a fast decay for a proportion of the fixed off-time, then to a slow decay for the remainder of the off-time. Mixed decay current control results in reduced audible motor noise, increased step accuracy, and reduced power dissipation.
The A4988 interface is an ideal fit for applications where a complex microprocessor is unavailable or is overburdened. During stepping operation, the chopping control in the A4988 automatically selects the current decay mode, Slow or Mixed. In Mixed decay mode, the device is set initially to a fast decay for a proportion of the fixed off-time, then to a slow decay for the remainder of the off-time. Mixed decay current control results in reduced audible motor noise, increased step accuracy, and reduced power dissipation.

This module comes pre-soldered, so is ready to use out of the box. We also include a small heatsink

Specifications
Minimum operating voltage: 8 V
Maximum operating voltage:35 V
Continuous current per phase: 1A (without heatsink or forced airflow)
Maximum current per phase:2A (With sufficient additional cooling)
Minimum logic voltage: 3 V
Maximum logic voltage: 5.5 V
Microstep resolutions: full, 1/2, 1/4, 1/8, and 1/16
Reverse voltage protection?: N

Maximum Ratings
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Electrical Characteristics
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Key Features
Simple step and direction control interface
Five different step resolutions: full-step, half-step, quarter-step, eighth-step, and sixteenth-step
Adjustable current control lets you set the maximum current output with a potentiometer, which lets you use voltages above your stepper motor’s rated voltage to achieve higher step rates
Intelligent chopping control that automatically selects the correct current decay mode (fast decay or slow decay)
Over-temperature thermal shutdown, under-voltage lockout, and crossover-current protection
Short-to-ground and shorted-load protection

Schematic
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Wiring Diagram
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Datasheet
Attachment:
HCMODU0068_Datasheet.pdf


Warning: This carrier board uses low-ESR ceramic capacitors, which makes it susceptible to destructive LC voltage spikes, especially when using power leads longer than a few inches. 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. 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.

Warning: Connecting or disconnecting a stepper motor while the driver is powered can destroy the driver.


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Tue Aug 19, 2014 2:34 pm
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