KNACRO DC 12V 3-Channel 30A Relay Control Module Bi-directional Isolated control module

VREF: photoelectric isolation control terminal reference ground, -If a high level control is used: this signal should be connected to the negative of the user's control panel power supply; -If low level control is used: this signal should be connected to the positive terminal of the user's control panel power supply; CH1-3: relay control interface, -If VREF is connected to the power supply negative: When this port is high level (relative to VREF), the corresponding relay is engaged; -If VREF is connected to the power supply positive: When this port is low level (relative to VREF), the corresponding relay is engaged; Note: the isolated relay module in order to adapt to the electromagnetic environment is relatively poor or relatively high signal requirements of the occasion, if you want to achieve a complete isolation effect, the user control panel power supply (that is connected to the VERF reference power) and the relay module power supply (DC + / DC-) should be separated, if the two power supply shared ground, then the effect is not fully isolated, then the user can use the standard relay module. Relay output: 9 interfaces, all interfaces have terminals, user-friendly wiring 1, NO1-NO3: relay normally open interface. 2, COM1-COM3: relay common interface. 3, NC1-NC3: relay normally closed interface. Package Included: 1*DC 12V 3-Channel 30A Relay Control Module