Module description:
1. The module adopts genuine quality relay, the maximum load of the normally open interface: AC 250V/10A, DC 30V/10A;
2. Using double optocoupler isolation, strong drive capability, stable performance; trigger current 5mA;
3. The module operating voltage is 5V;
4. Each channel of the module can be triggered by jumper high or low level;
5. Fault-tolerant design, even if the control line is broken, the relay will not move;
6. Power indicator (green), 4 relay status indicators (red)
7. User-friendly interface design, all interfaces can be directly connected through the wiring terminals, very convenient

Module interface:
1. DC+: Connect to the positive pole of the power supply (Pressure relay 5V)
2. DC-: Connect to the negative pole of the power supply
3. IN1-IN4: According to the setting of each channel, the corresponding relay can be controlled by high or low level.

Relay output:
1. NO1-NO4: Normal open interface of the relay. Before the relay is closed, it is left unconnected. After picking up, it is shorted to COM.
2. COM1-COM4: Relay Common Interface
3. NC1-NC4: Normally closed relay interface. Before the relay is closed, it is short-circuited with COM.

High and low level trigger selection:
1. S1-S4 is the high and low level trigger selection for Relay 1-4 channel;

2. When com is shorted to low, the corresponding relay is a low level trigger. When com is shorted to high, it is a high level trigger.