HX711 Detailed explanation of pin function specifications and circuit principle instructions

The HX711 is a precision 24-bit analog-to-digital converter (ADC) used primarily in weigh scales and industrial control applications to interface with load cells. The HX711 is not associated with a specific brand; rather, it is a part of various components used by different manufacturers. The component's specifications are often used in load-cell systems for weight measurement.

Let's break down the requested details step by step:

Pinout and Pin Functionality (HX711)

The HX711 has a 16-pin package (most commonly in a dual inline package, or DIP, configuration). Here’s a breakdown of its pinout:

Pin Number Pin Name Pin Description 1 VCC Power supply (typically 5V) 2 GND Ground 3 DT Data pin (Digital output from HX711 to microcontroller) 4 SCK Clock pin (Serial clock for communication) 5 NC No connection (reserved or not used) 6 NC No connection (reserved or not used) 7 A- Input for load cell negative (Channel A) 8 A+ Input for load cell positive (Channel A) 9 B- Input for load cell negative (Channel B) 10 B+ Input for load cell positive (Channel B) 11 NC No connection (reserved or not used) 12 NC No connection (reserved or not used) 13 NC No connection (reserved or not used) 14 NC No connection (reserved or not used) 15 NC No connection (reserved or not used) 16 NC No connection (reserved or not used)

Full Pin Function and Usage Description

VCC (Pin 1): This is the power input pin. The HX711 typically operates on a 5V power supply, but it can also work with a supply range of 2.7V to 5.5V. This is where the 5V power for the chip is provided.

GND (Pin 2): Ground pin. It connects to the ground of the circuit, providing the return path for electrical current.

DT (Pin 3): The Data pin is used to transmit data to the microcontroller. It outputs the 24-bit data stream representing the load cell readings. The data can be read serially when the clock (SCK) is pulsed.

SCK (Pin 4): The Serial Clock pin is used to clock data out from the HX711. It signals the chip to transfer data when it is pulsed. Each pulse of the SCK pin shifts out 1 bit of data.

A- (Pin 7) and A+ (Pin 8): These pins are for the differential input from the load cell’s channel A. The HX711 is typically configured for single-ended or differential mode with one load cell connected to this channel. In a load cell configuration, A+ connects to the positive terminal, and A- connects to the negative terminal of the load cell.

B- (Pin 9) and B+ (Pin 10): These pins are for the differential input for load cell channel B. In most cases, only channel A is used in most applications, but this channel can be used for a second load cell or as a differential input for more accurate measurements.

Pin FAQ (20 Common Questions)

1. What is the maximum voltage the HX711 can tolerate on its VCC pin? The HX711 can tolerate 5.5V on the VCC pin.

2. What is the typical operating voltage for the HX711? The typical operating voltage is 5V, but it can work in a range of 2.7V to 5.5V.

3. What does the DT pin do? The DT pin is used for serial data output. It sends a 24-bit digital data stream representing the measurement from the load cell.

4. Can I connect multiple load cells to the HX711? Yes, the HX711 supports two input channels, A and B, which allow you to connect two load cells, one to each channel.

5. How does the SCK pin function? The SCK pin is the clock input. When pulsed, it shifts data out of the DT pin.

6. Why is there a “no connection” (NC) pin on the HX711? The NC pins are unused and serve no function. They are reserved for possible future versions or configurations of the chip.

7. What is the difference between Channel A and Channel B on the HX711? Channel A is the primary channel for load cell measurements, while Channel B can be used for a second load cell or as an alternative mode for higher precision.

8. Can I use the HX711 without a load cell? No, the HX711 is designed to interface specifically with load cells for weight measurement.

9. How do I read data from the HX711? Data can be read by sending pulses to the SCK pin, which shifts out data on the DT pin.

10. Can I use the HX711 with a microcontroller? Yes, the HX711 is designed to be interfaced with microcontrollers, such as Arduino, for weight measurement applications.

11. What is the resolution of the HX711? The HX711 has a 24-bit resolution, meaning it can convert signals from the load cell with high accuracy.

12. Is there any need for external components when using the HX711? You generally need to connect the HX711 to a microcontroller and load cell, but additional filtering capacitor s may be recommended for stability.

13. How does the HX711 handle noise from the load cell signal? The HX711 features internal amplification and filtering to handle small load cell signals, minimizing the impact of noise.

14. What is the maximum clock speed for the HX711? The clock speed of the HX711 is typically limited to 10Hz for accurate data transfer.

15. Does the HX711 require any calibration? Yes, calibration is required to convert the raw data into a meaningful weight value. This involves using known weights to adjust the readings.

16. Can the HX711 operate with a 3.3V power supply? Yes, the HX711 can operate at 3.3V, but you might need level shifting for the SCK and DT pins when interfacing with a 3.3V microcontroller.

17. Is there an internal reference voltage in the HX711? Yes, the HX711 includes an internal reference voltage that determines the input signal’s range.

18. How do I reset the HX711? To reset the HX711, you can power cycle the device or use specific commands via the microcontroller interface.

19. What is the default gain of the HX711? The default gain for channel A is 128, which can be adjusted based on the requirements of your application.

20. Can the HX711 be used in industrial applications? Yes, the HX711 is widely used in industrial applications such as weighing scales and material measurement systems due to its high precision.

This explanation covers the pinout, detailed functionality of each pin, and a FAQ section with comprehensive answers. For further clarity, if you need any specific configuration or additional explanations on interfacing with certain devices, feel free to ask!