Электронный магазин частей для минироботов Миниробо

Описание

Описание

Данный продукт представляет собой плату с установленными на него микрошаговым драйвером A4983 DMOS от Allegro и схемы обвязки, поэтому мы рекомендуем внимательно ознакомиться с документацией на  A4983 (368k PDF) перед использованием этого продукта. Драйвер шагового двигателя позволяет управлять одним биполярным шаговым мотором током до 2 А на катушку. Вот некоторые из основных особенностей драйвера:

• 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
• 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

Included Hardware
The A4983 stepper motor driver carrier comes with one 1×16-pin breakaway 0.1" male header. The headers can be soldered in for use with solderless breadboards or 0.1" female connectors. You can also solder your motor leads and other connections directly to the board.

Using the driver

Power connections
The driver requires a logic supply voltage (3 – 5.5 V) to be connected across the VDD and GND pins and a motor supply voltage of (8 – 35 V) to be connected across VMOT and GND. These supplies should have appropriate decoupling capacitors close to the board, and they should be capable of delivering the expected currents (peaks up to 4 A for the motor supply).

Размер шага (и микрошага)
Шаговые двигатели, как правило, имеют спецификацию шага (например, 1,8 ° или 200 шагов на оборот), которая применяется к полным шагам. Микрошаговый драйвер такой как A4983 позволяют получить более высокое разрешение путем определения промежуточных шагов, что достигается за счет возбуждения катушек с промежуточными токовыми уровнями. Например, двигатель имеющий 200-шагов на оборот в четверть-шаговом режиме, с помощью четырех различных токовых уровней, даст 800 микрошагов на оборот.

Входы MS1, MS2, MS3 - это селектор входов разрешения (размер шага) который предоставляет выбор из пяти разрешений в соответствии с таблицей ниже. MS2 and MS3 have internal 100kΩ pull-down resistors, but MS1 does not, so it must be connected externally. For the microstep modes to function correctly, the current limit must be set low enough (see below) so that current limiting gets enganged. Otherwise, the intermediate current levels will not be correctly maintained, and the motor will effectively operate in a full-step mode.

Control inputs
Each pulse to the STEP input corresponds to one microstep of the stepper motor in the direction selected by the DIR pin. The chip has three different inputs for controlling its many power states: RST, SLP, and EN. For details about these power states, see the datasheet. Please note that the RST pin is floating; if you are not using the pin, you can connect it to the adjacent SLP pin on the PCB. 

Current limiting
To achieve high step rates, the motor supply is typically much higher than would be permissible without active current limiting. For instance, a typical stepper motor might have a maximum current rating of 1 A with a 5Ω coil resistance, which would indicate a maximum motor supply of 5 V. Using such a motor with 12 V would allow higher step rates, but the current must actively be limited to under 1 A to prevent damage to the motor.

The A4983 supports such active current limiting, and the trimmer potentiometer on the board can be used to set the current limit. An easy way to set the current limit is to put the driver into full-step mode and to measure the supply current to the board without clocking the STEP input. The measured current will be 1.4 times the current limit (since both coils are always on and limited to 70% in full-step mode). Please note that the current limit is dependent on the Vdd voltage.

Another way to set the current limit is to measure the voltage on the “ref” pin and to calculate the resulting current limit (the current sense resistors are 0.05Ω). The ref pin voltage is accessible on a via that is circled on the bottom silkscreen of the circuit board.

Schematic Diagram

FAQ`s

FAQ`s

Ресурсы

Ресурсы

Галерея

Галерея