- The supply voltage of 8.2 V - 45 V
- Continuous current through the coil: 0.75 A
- Maximum short-term current per coil: 1.2 A
- Voltage digital logic supply: 2.5 V To 5.25 V
- Resolution: 1, 1/2, 1/4, 1/8, 1/16, and 1/32-step
The module is based on the DRV8824 driver of Texas Instruments, allows you to control a stepper motor with maximum current consumption of up to 0.75 A per coil (with the use of cooling up to 1.2 A). Is supplied with the voltage in the range from 8.2 Volts to 45 VOLTS. It is recommended to see the documentation driver the DRV8824. Below are some of the characteristics of the main product:
- The module has a simple control interface step and direction
- Has the capability of operating in six modes: full-step, half-step, 1/4-step, 1/8-step, 1/16-step, and 1/32-step
- Provides control of maximum motor current with the potentiometer, which allows the use of higher than the nominal supply voltage for the stepper motors, this allows you to get a higher speed of execution of steps
- The engines can be powered with voltage from 8.2 V to 45 V
- Maximum input current 1.2 A ( 0.75 A without external cooling)
- Thanks to the built-in voltage regulator, you should not allow additional power logical parts.
- DRV8824 works with systems with a voltage of logical parts such as 3.3 V and 5V.
- Is protected against too high current and temperature and short circuit protection and interlock system for the start at low voltage
- To increase the surface oddającej warmth tiles have been manufactured in technology czterowarstwowej roughly cover copper
- The open fields of the mass from the bottom allowing you to solder the cooling elements
- The module is compatible from the point of view of dimensions and insights with a system based on driver A4988
In our offer there is also a version DRV8825 for engines with higher power. DRV8825 allows for input currents up to 1.5 A to the coil (up to 2.2 And with additional cooling).
The set includes all the essential elements for driver connection module and connector for self soldering. On request, we can provide the model with zlutowanymi senior. For this purpose, please leave the details in comments to the order.
To control a stepper motor bipolarnym it is necessary to connect the system in accordance with the following figure. The driver allows to work with some engines unipolarnymi, the details are in the instructions.
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. Conclusions 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 power control: RESET SLP and EN, their description is in documentation. Please note that these conclusions are connected to anything. If they will not be used to control the power modes, it is necessary to pull them outwardly to the supply voltage (specify the status of the highest logical unit in the range of 2.2 V to 5.5 V).
The DRV8824 driver also has output marked as a FAULT. The status of the low (logical zero) indicates the occurrence of disturbances in the system, for example, the tripping of safety. On the Board output is connected with the contact SLEEP, and thus giving a high position to SLEEP pulls the pin to VCC (pull-up), as well as GUILT. Through the application of consistent protective resistor output "FAULT" can also be connected to the voltage VCC, which makes the module is pin-compatible with the version of the A4988.
The chip can be powered with voltage from a range of 8.2 Volts to 45 VOLTS is connected between the terminal UMOT (+) and GND (-). The voltage must be filtered through the external capacitor placed as close as possible to the tile driver. Its capacity depends on the maximum current consumed by the motor.
In certain conditions, even a relatively low supply voltage may lead to stiletto high amplitude, exceeding the allowed value of 45 V. This situation causes irreversible damage to the system. One way to avoid this problem is the placement of the capacitor (at least 47 uF) as close as possible to UMOT and GND pins of the controller.
The connection and disconnection of the engine while the driver is turned on can damage the system.
Driver mikrokrokowy like the DRV8824 allows engine operation with high resolution to 1/32 step. The step size is selected via inputs MODE1, MODE1 and MODE2 - available modes are presented in the table below. By default, all three pins they downloaded to ground via a resistor (pull-down) 100kΩ. Leave them not connected means that the choice of mode full step. For example, when using a motor with a resolution of 200 steps per revolution, mode ¼ steps means working with a resolution of 800 positions per revolution.
To maintain high switching speed steps, you can use a higher motor supply voltage than nominal. You should only limit the maximum current value (directory engine) passing through the coil.
The module 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 at pin REF (marked with a circle on the PCB), as well as the calculation of the current limit (measuring resistors have a value of 0.330 Ohm). The current limit can be calculated from the formula:
Current Limit = VREF * 0,61
For example, if the engine can get up to 0.5 A, the voltage reference VREF of the pine trees must have a value of 0.82 V.
The tile was designed so that it can conduct heat when the current consumption is about 0.5 A to the coil. If the current is significantly higher, you should use an external radiator, which can be installed using 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.
The main differences from version A4888
Module DRV8824 was designed to be compatible with the version of the system, based on A4988. The plates have the same shape, size and location of the contacts. However, there are several different between them:
- Pin is used as supply voltage logic part of the A4988 has been replaced with the FAULT contact because the DRV8825 does not require additional power. FAULT connected through a protective resistor, and hence may be used in system design for the A4988 module, this pin is the supply voltage, in the list of logical (2,2 V to 5,5 V).
- In module DRV8824 SLEEP pin default pulled up through a resistor pull-up) for power, combined with a FAULT output through a 10K resistor. In systems designed under the A4988 chip, using a voltage of a logic part connected to the FAULT, the 10K resistor pulls the SLEEP voltage setting is high.
- The potentiometer which limits the maximum current for motors is in a different place
- DRV8824 allows you to work in 1/32 steps, while in the A4988 worked down to 1/16-step
- DRV8824 has lower energy efficiency, but has a wider supply voltage range 45 Volts (A4988 to 35 V), which also makes it less vulnerable to short electric pulses of high amplitude (so-called studs)
- O have different names but perform the same function