- The motor supply voltage: 4.5 V to 35 V
- Current: max 1.8 A per coil ( in the cooling up to 2.5 A)
- Voltage digital logic supply from 3.3 V to 5 V
- The simple control interface
- Work in 4 different modes: full step, 1/2, 1/4 and 1/8
- The ability to adjust the current consumed by the motor with a potentiometer
- Overheat protection system
- Module dimensions: 20 x 15 mm
The system allows you to control a stepper motor using a device that allows you to generate the logical state, for example, Aa rduino, STM32Discovoery, Raspberry Pi or any microcontroller. The Pololu module is characterized by a very simple operation. 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 as the output DIR (e.g., low - speed clockwise, as high - on the contrary). The driver also has the choice of resolution of operation of the engine.
To control a stepper motor bipolarnym it is necessary to connect the system in accordance with the following figure. In the case of engine control unipolarnym must read the instructions. If the nominal motor voltage is lower than the required power of the driver (4.5 V), manually, using a potentiometer to set the current limit.
The illustration shows the minimum connection driver. Between the power terminal of motor and ground, you need to put a resistor values are +/- 100 UF
To power the logic part of the module requires a voltage range of 2.5 V to 5 V, which should be brought into contact Sleep. The motor supply voltage range from 4.5 V to 35 V is supplied to pin UMOT. The system can control the engines with a rated voltage lower than the required 4.5 V. In this case, it is necessary to limit the maximum current draw not to exceed the permissible current 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. the Power voltage of 12 V to limit the current, so it does not exceed 1 A.
The connection and disconnection of the engine while the driver is turned on can damage the system.
The step size is selected via the inputs MS1, MS2. Possible settings are shown in the table below. Inputs MS1 and MS2 have an internal resistor pull-down (500 kOhm).
One pulse on the specified pin STEP causing one step of the motor in the direction selected by making the appropriate logic state on the output DIR. If the motor should only rotate in one direction, pin leave the disconnected DIR.
The system has two different inputs for power management: SLEEP, and ENBL their description is in the documentation. Please note that the driver pulls both pins through the internal resistors, reducing 500 ohms. The default state of the SLEEP blocks the operation of the engine, must be in the specified status high (can be connected directly to a power source logic from 2.5 to 5 Volts or can be controlled via the connection to the digital output of the MICROCONTROLLER). The default state of the ENBL to enable the driver, can be disabled.
The FAULT output turns off when the bridges F and H are disabled as a result of overcurrent, overvoltage, or thermal shutdown protection under voltage protection. Is connected to the contact SLEEP through resistor 10 KOhm, which works the same as FAULT. When SLEEP is high status, does not require a connection FAULT.
In the result of the connection, DISCONNECTION and CRASH and malfunction, the voltage at the pines SLEEP may fall below 2.1 V if it is not strengthened enough. It is recommended to use a braking resistor min. 4,7 kOhm with this conclusion or SLEEP connected directly to VCC.
The system can control the engines with a rated voltage lower than the required 4.5 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. the Power voltage of 12 V to limit the current, so it does not exceed 1 A.
Module MP6500 allows the active current limit with the potentiometer. One of the ways the introduction of restrictions to set the driver to full step and measuring the current passing through one coil without signal at the input STEP. The measured current is 70% of the established limit (both coils are always on and limited to 70% of full step). Another way is to measure the voltage on the VREF pin (marked with a circle on the PCB), as well as the calculation of the current limit (measuring resistors have a value of 0.05 Ohms). More detail in the documentation of the MP6500 system.
The tile was designed so that it can conduct heat when the current consumption of about 1.8, And the coil. If the current is much higher, use an external heatsink to which the Assembly can use glue termoprzewodzącego.
The system includes the necessary passive components for the correct operation of the driver. The scheme of connection shown in the figures below.