24VDC Quad (4 Channel) Relay Module

The 4 Channel 24V Relay Module is a control interface device designed for industrial automation and PLC applications. Here's a comprehensive breakdown:

Key Specifications:
- Operating voltage: 24V DC
- Contact ratings: AC 250V/10A, DC 30V/10A (max load)
- Trigger current: 5mA
- Dimensions: 73mm × 50mm × 18.5mm (L × W × H)
- Mounting hole pattern: 67mm × 44.5mm pitch, 3.1mm diameter holes

Technical Features:
1. Isolation and Safety
- SMD optocoupler isolation for electrical safety
- Fault-tolerant design prevents relay activation if control line breaks
- OPTO-isolation provides protection between control and load circuits

2. Interface Configuration
- 4 independent relay channels
- Each channel configurable for high or low level triggering via jumper
- Terminals for all connections (control inputs and relay contacts)

3. Contact Arrangements (per channel)
- NO (Normally Open) contacts
- NC (Normally Closed) contacts
- COM (Common) terminals
- All contacts rated for 10A switching current

4. Status Indication
- Green power indicator LED
- 4 red LEDs for individual relay status
- Visual confirmation of operation

5. Control Interface
- IN1 through IN4 control inputs
- Selectable trigger logic (high/low) via S1-S4 jumpers
- COM terminal for trigger reference

Installation Features:
- Panel mount design
- 4 mounting holes for secure installation
- Terminal block connections for all wiring
- Direct wire connection capability without special connectors

Applications:
- PLC integration
- Industrial automation
- Equipment control
- Process automation
- Power switching applications

This module offers professional-grade features like optocoupler isolation and configurable triggering while maintaining ease of use through straightforward terminal connections and clear status indicators.

Basic Relay Operation: A relay is essentially an electrically controlled switch. When voltage is applied to the control input (IN1-IN4), it energizes an internal coil through the optocoupler, which mechanically switches the contacts. The optocoupler provides electrical isolation between your control circuit (CNC controller) and the switched load circuit.

Contact States:

• NO (Normally Open): Circuit is open until relay is energized
• NC (Normally Closed): Circuit is closed until relay is energized
• COM (Common): The common terminal that switches between NO and NC

Connection to CNC Controller:

1. Power Supply Connection:

• Connect 24V DC power supply to the module:
  • DC+ to positive terminal
  • DC- to negative/ground terminal

2. Control Signal Connection:

• From CNC controller outputs to relay module:
  • Connect controller's ground/COM to relay module's DC-
  • Connect controller's output signals to IN1-IN4
  • Set appropriate trigger jumpers (S1-S4) based on controller output type:
    • For active-high outputs: Set jumper to "H"
    • For active-low outputs: Set jumper to "L"

3. Load Connection (for each channel):

• For devices you want to turn ON when activated:
  • Connect one wire to COM terminal
  • Connect other wire to NO terminal
• For devices you want to turn OFF when activated:
  • Connect one wire to COM terminal
  • Connect other wire to NC terminal

Common CNC Applications:

1. Spindle control
2. Coolant pump control
3. Vacuum/dust collection activation
4. Tool changer operation
5. Emergency stop integration

Safety Considerations:

1. Always verify voltage compatibility between CNC controller and relay module
2. Ensure proper grounding
3. Use appropriate wire gauge for load current
4. Keep high-voltage connections well-insulated
5. Consider adding flyback diodes for inductive loads
6. Double-check all connections before powering up

Example Connection for Spindle Control:

This creates a switched circuit where the spindle only receives power when the CNC controller activates the relay.

Current Limitations:

• Stay within 10A per channel
• For larger loads, use these relays to control larger contactors
• Consider duty cycle for repetitive operations

Testing Setup:

1. Before connecting to actual loads:

• Power up the relay module
• Trigger each input manually
• Verify LED indicators work
• Listen for relay clicking
• Use multimeter to verify contact switching

2. After connecting loads:

• Test each function at low speed/power first
• Verify emergency stop functionality
• Check for any unusual heating