How to Use БК-24-RS485-01: Examples, Pinouts, and Specs

The БК-24-RS485-01 is a robust communication module manufactured by Bolid, designed for RS-485 serial communication. It facilitates reliable and efficient data transmission over long distances, making it ideal for industrial and commercial applications. The module supports multi-device communication on a single bus, adhering to the RS-485 standard, which ensures noise immunity and differential signaling for enhanced reliability.

• Industrial automation and control systems
• Building management systems (BMS)
• Security and fire alarm systems
• Data acquisition and monitoring
• Communication between microcontrollers and PLCs
• Long-distance serial communication in noisy environments

1. Power Supply: Connect the V+ pin to a regulated 24V DC power source and the GND pin to the ground of the power supply.
2. RS-485 Bus Connection:
   • Connect the A (Data+) and B (Data-) pins to the corresponding lines of the RS-485 bus.
   • Use twisted-pair cables for the A and B lines to minimize noise and signal degradation.
3. Shielding: Connect the Shield pin to the cable shield or ground to improve noise immunity.
4. Termination Resistor: If the module is at the end of the RS-485 bus, add a 120-ohm termination resistor between the A and B lines to prevent signal reflections.
5. Device Addressing: Ensure each device on the RS-485 bus has a unique address to avoid communication conflicts.

• Cable Selection: Use high-quality, twisted-pair cables with shielding for long-distance communication.
• Grounding: Properly ground the module to prevent ground loops and ensure stable operation.
• Baud Rate: Match the baud rate of all devices on the RS-485 bus for successful communication.
• Device Count: Do not exceed the maximum of 32 devices on a single RS-485 bus without using repeaters.
• Electrostatic Discharge (ESD) Protection: Handle the module with care to avoid damage from ESD.

The БК-24-RS485-01 can be used with an Arduino UNO for RS-485 communication. Below is an example of how to connect and program the module:

#include <SoftwareSerial.h>

// Define RS-485 communication pins
#define RX_PIN 3  // Arduino pin connected to RS-485 Data- (B)
#define TX_PIN 2  // Arduino pin connected to RS-485 Data+ (A)

// Initialize SoftwareSerial for RS-485 communication
SoftwareSerial rs485Serial(RX_PIN, TX_PIN);

void setup() {
  // Start serial communication for debugging
  Serial.begin(9600);
  Serial.println("RS-485 Communication Test");

  // Start RS-485 communication
  rs485Serial.begin(9600);
}

void loop() {
  // Send data over RS-485
  rs485Serial.println("Hello from Arduino!");

  // Check if data is available to read
  if (rs485Serial.available()) {
    String receivedData = rs485Serial.readString();
    Serial.print("Received: ");
    Serial.println(receivedData);
  }

  delay(1000); // Wait for 1 second
}

1. No Communication Between Devices

   • Cause: Incorrect wiring or mismatched baud rates.
   • Solution: Verify the A and B lines are correctly connected and ensure all devices use the same baud rate.

2. Signal Degradation Over Long Distances

   • Cause: Poor-quality cables or lack of termination resistors.
   • Solution: Use high-quality, twisted-pair cables and add 120-ohm termination resistors at both ends of the RS-485 bus.

3. Interference or Noise in Communication

   • Cause: Improper shielding or grounding.
   • Solution: Ensure the Shield pin is connected to the cable shield or ground.

4. Overheating of the Module

   • Cause: Exceeding the power supply voltage or improper ventilation.
   • Solution: Use a regulated 24V DC power supply and ensure adequate airflow around the module.

Q1: Can the БК-24-RS485-01 be used outdoors?
A1: The module is designed for industrial environments but should be housed in a weatherproof enclosure for outdoor use.

Q2: How many devices can I connect to a single RS-485 bus?
A2: The module supports up to 32 devices on a single bus. For more devices, use RS-485 repeaters.

Q3: What is the maximum communication distance?
A3: The maximum distance is 1200 meters at a baud rate of 9600 bps. Higher baud rates may reduce the effective distance.

Q4: Is the module compatible with 5V microcontrollers?
A4: Yes, but you will need a 5V to 24V DC converter for the power supply. Ensure proper voltage level shifting for data lines if required.