Description: Stepper motor driver A4988 RepRap - green
Designed for 3D printers chip driver A4988 allows you to control a stepper motor with active limitation of the maximum current.
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Despite the fact that the quality of performance of print and soldermask is not high, the controller remains fully operating. In our offer you will also find high quality module A4988 from Pololu company. |
Connection driver
In order to rotate the motor one step, you must specify the STEP output high (logical unit), another sequence of zeros and ones moves the motor one step, etc. The choice of direction is accomplished by depositing a correct state on the output DIR (e.g. low - momentum clockwise, low - counterclockwise). The driver also has the choice of resolution of the motor operation.
Power supply
To power the logic part of the module, you need the voltage range from 3 V to 5.5 V, which should be brought into contact VDD. The motor supply voltage is in the range from 8 V to 35 V is supplied to pin UMOT.
The system can control the motors with a rated voltage lower than the required 8 V. In this case, it is necessary to limit the maximum current through the potentiometer, so as not to exceed the maximum voltage of the motor. For example, for a motor with a resistance of 5 Ohms on the coil and a current consumption of 1 A, the nominal supply voltage of 5 V. Power voltage of 12 V to limit the current, so it does not exceed 1 A.
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Attention! The connection and disconnection of the motor while the driver is turned on can damage the system. |
Resolution
The step size is selected via the inputs MS1, MS2, MS3. Possible settings are shown in the table below. Inputs MS1, MS2 and MS3 have internal resistor pull-down (100 kω).
| MS1 | MS2 | MS3 | Resolution |
| low | low | low | Full step |
| high | low | low | 1/2 step |
| low | high | low | 1/4 step |
| high | high | low | 1/8 step |
| high | high | high | 1/16 step |
One pulse on the specified pin STEP causes one step of the motor in the direction selected by making the appropriate logic state on the output DIR. Outputs STEP and DIR are not internally pulled up. If the motor should only rotate in one direction the DIR pin can be permanently connected to VCC or GND.
The system has three inputs for monitoring power consumption: SLP EN RESET and their description is in documentation. Please note that the pin RESET to nothing pulled. If not used, you can connect it to the surrounding contact SLEEP.
Current limit
The system can control the motors with a rated voltage lower than the required 8 V. In this case, it is necessary to limit the maximum current through the potentiometer, so as not to exceed the maximum voltage of the motor. For example, for a motor with a resistance of 5 Ohms on the coil and a current consumption of 1 A, the nominal supply voltage of 5 V. Power voltage of 12 V to limit the current, so it does not exceed 1 A.
Heat
The board was designed so that it can conduct heat when the current consumption is about 1A per coil. If the current is much higher, use an external heatsink to which the assembly can use thermoconductive glue.
Specification of stepper motor driver A4988 RepRap:
- Motor supply voltage: 8 V to 35 V
- Current: 1 a max. per coil
- Voltage digital logic supply: 3 V - 5.5 V
- Simple control interface
- Work in 5 different modes: full step, 1/2, 1/4, 1/8 and 1/16 step
- Ability to adjust the current consumed by the motor with a potentiometer
- Soldered goldpin connectors
Useful links |
