How to Use TK4S-24RR: Examples, Pinouts, and Specs

The TK4S-24RR is a solid-state relay (SSR) designed for efficient and reliable switching applications. Unlike mechanical relays, the TK4S-24RR uses semiconductor components to perform switching, ensuring a longer lifespan and faster operation. Its compact design and high reliability make it an excellent choice for controlling AC loads with minimal input power. Additionally, the relay provides electrical isolation between the control and load circuits, enhancing safety and performance.

• Industrial automation systems
• HVAC (Heating, Ventilation, and Air Conditioning) control
• Motor control and protection
• Lighting systems
• Home and building automation

1. Input Side (Control Circuit):

   • Connect the positive terminal of the DC control signal to the Input (+) pin.
   • Connect the negative terminal of the DC control signal to the Input (-) pin.
   • Ensure the input voltage is within the specified range (3-32 VDC).

2. Output Side (Load Circuit):

   • Connect the AC load between the Output (AC1) and Output (AC2) pins.
   • Ensure the load does not exceed the maximum output current rating (4 A).

3. Power Supply:

   • Verify that the AC load voltage is within the specified range (24-240 VAC).
   • Use appropriate fuses or circuit breakers to protect the relay and load.

4. Mounting:

   • The TK4S-24RR is designed for PCB mounting. Ensure proper soldering and spacing to avoid short circuits.

• Heat Dissipation: Ensure adequate ventilation or heat sinking to prevent overheating during operation.
• Electrical Isolation: The relay provides isolation between the control and load circuits, but ensure proper grounding for safety.
• Inductive Loads: When switching inductive loads (e.g., motors), use a snubber circuit or varistor to suppress voltage spikes.
• Testing: Before connecting the relay to a live load, test the control circuit with a multimeter to ensure proper operation.

The TK4S-24RR can be easily controlled using an Arduino UNO. Below is an example circuit and code to toggle an AC load using the relay.

• Connect the Input (+) pin of the relay to Arduino digital pin 7.
• Connect the Input (-) pin of the relay to the Arduino GND.
• Connect the AC load to the Output (AC1) and Output (AC2) pins of the relay.

// Define the pin connected to the relay
const int relayPin = 7;

void setup() {
  // Set the relay pin as an output
  pinMode(relayPin, OUTPUT);
  
  // Start with the relay off
  digitalWrite(relayPin, LOW);
}

void loop() {
  // Turn the relay on (AC load ON)
  digitalWrite(relayPin, HIGH);
  delay(5000); // Keep the load on for 5 seconds
  
  // Turn the relay off (AC load OFF)
  digitalWrite(relayPin, LOW);
  delay(5000); // Keep the load off for 5 seconds
}

1. Relay Not Switching:

   • Cause: Insufficient input voltage or current.
   • Solution: Verify that the control signal is within the specified range (3-32 VDC).

2. Overheating:

   • Cause: Excessive load current or poor ventilation.
   • Solution: Ensure the load does not exceed 4 A and provide adequate cooling.

3. AC Load Not Turning On:

   • Cause: Incorrect wiring or damaged relay.
   • Solution: Double-check the wiring and test the relay with a multimeter.

4. Voltage Spikes When Switching Inductive Loads:

   • Cause: Lack of a snubber circuit or varistor.
   • Solution: Add a snubber circuit or varistor across the output terminals.

Q1: Can the TK4S-24RR switch DC loads?
A1: No, the TK4S-24RR is designed specifically for AC loads. For DC loads, use a DC-specific solid-state relay.

Q2: What is the maximum switching frequency?
A2: The relay has a switching speed of ≤10 ms, making it suitable for low to moderate frequency applications.

Q3: Is the relay polarity-sensitive on the input side?
A3: Yes, the Input (+) and Input (-) pins must be connected correctly to the DC control signal.

Q4: Can I use the relay without a microcontroller?
A4: Yes, the relay can be controlled using any DC voltage source within the specified range (e.g., a 5 V power supply).

By following this documentation, users can effectively integrate the TK4S-24RR into their projects and troubleshoot common issues with ease.