How to Use OXY-LC Interface Board: Examples, Pinouts, and Specs

The OXY-LC Interface Board (OXY-LC-485), manufactured by SST Sensing, is a specialized circuit board designed to interface with OXY-LC oxygen sensors. It facilitates seamless communication and data transfer between the sensor and external devices such as microcontrollers, PLCs, or industrial systems. The board supports RS-485 communication, making it suitable for robust and long-distance data transmission in industrial and environmental monitoring applications.

• Industrial Process Control: Monitoring oxygen levels in manufacturing processes.
• Environmental Monitoring: Measuring oxygen concentration in air or water.
• Medical Equipment: Integration into devices requiring precise oxygen sensing.
• Research and Development: Prototyping and testing oxygen sensor-based systems.

1. Power Supply: Connect a regulated 5V DC power supply to the VCC and GND pins of the interface board.
2. Sensor Connection: Attach the OXY-LC sensor to the 4-pin Molex connector on the board.
3. RS-485 Communication: Connect the A (TX+) and B (TX-) pins to the RS-485 bus of your microcontroller or PLC.
4. Baud Rate Configuration: Ensure the baud rate of your microcontroller matches the default or configured baud rate of the interface board (default: 9600 bps).
5. Data Reading: Use the RS-485 protocol to send commands and receive oxygen concentration data from the sensor.

• Power Supply: Use a stable and noise-free 5V DC power source to avoid communication errors.
• Termination Resistor: For long RS-485 bus lines, add a 120-ohm termination resistor between A and B lines at both ends of the bus.
• Grounding: Ensure a common ground between the interface board and the connected device.
• Cable Length: RS-485 supports long cable runs, but keep the length within 1200 meters for reliable communication.
• Sensor Warm-Up: Allow the sensor to stabilize for a few seconds after powering up before taking measurements.

Below is an example of how to interface the OXY-LC Interface Board with an Arduino UNO using an RS-485 module.

#include <SoftwareSerial.h>

// Define RS-485 communication pins
#define RX_PIN 10  // Arduino pin connected to RS-485 RX
#define TX_PIN 11  // Arduino pin connected to RS-485 TX

// Create a SoftwareSerial object for RS-485 communication
SoftwareSerial rs485Serial(RX_PIN, TX_PIN);

void setup() {
  // Initialize serial communication for debugging
  Serial.begin(9600);
  // Initialize RS-485 communication
  rs485Serial.begin(9600);

  Serial.println("OXY-LC Interface Board Communication Started");
}

void loop() {
  // Send a command to the OXY-LC sensor (example command: 0x01 0x03 0x00 0x00 0x00 0x01 0x85 0xDB)
  byte command[] = {0x01, 0x03, 0x00, 0x00, 0x00, 0x01, 0x85, 0xDB};
  rs485Serial.write(command, sizeof(command));

  // Wait for a response
  delay(100);

  // Check if data is available
  if (rs485Serial.available()) {
    Serial.print("Sensor Response: ");
    while (rs485Serial.available()) {
      byte response = rs485Serial.read();
      Serial.print(response, HEX);
      Serial.print(" ");
    }
    Serial.println();
  }

  // Wait before sending the next command
  delay(1000);
}

• Replace the example command with the appropriate command for your specific application.
• Ensure the RS-485 module is properly connected to the Arduino UNO.

1. No Communication with the Sensor

   • Cause: Incorrect baud rate or wiring.
   • Solution: Verify the baud rate and ensure proper connections between the interface board, RS-485 module, and microcontroller.

2. Unstable Readings

   • Cause: Noisy power supply or improper grounding.
   • Solution: Use a regulated power supply and ensure a common ground between devices.

3. Data Corruption on Long Cables

   • Cause: Missing termination resistors.
   • Solution: Add 120-ohm termination resistors at both ends of the RS-485 bus.

4. Sensor Not Responding

   • Cause: Sensor not properly connected or damaged.
   • Solution: Check the sensor connection and replace the sensor if necessary.

• Q: Can I use a 3.3V microcontroller with the OXY-LC Interface Board?
  A: Yes, but you will need a level shifter to convert the 3.3V logic to 5V for RS-485 communication.

• Q: What is the maximum cable length supported by RS-485?
  A: RS-485 supports cable lengths up to 1200 meters, but ensure proper termination and shielding for long runs.

• Q: How do I change the baud rate of the interface board?
  A: Refer to the OXY-LC Interface Board user manual for instructions on configuring the baud rate.

• Q: Can I connect multiple sensors to the same RS-485 bus?
  A: Yes, RS-485 supports multi-drop communication. Assign unique addresses to each sensor.

This documentation provides a comprehensive guide to using the OXY-LC Interface Board effectively. For further assistance, consult the manufacturer's datasheet or technical support.