Feature:
Module Size: 73*50*18.5mm
With 4 fixed bolt holes, diameter 3.1mm, spacing 44.5*67mm

High and low level trigger selection:
Trigger current is 2-4mA, trigger low level is 0-4V, trigger high level is 4.5-12V 
1. S1 1 way relay high or low level trigger selection;
2. S2 2 way relay high or low level trigger selection;
3. com and low in short circuit, the relay is low level trigger, com and high end in short circuit, the relay is high level trigger.

Input Interface:
1. DC+: to connect the power positive (voltage as the relay required 12V)
2. DC-: to connect the power negative 
3. IN1-IN4:can set the high or low level control relay

Output Interface:
1. NO1-NO4: relay normally open interface, suspend the relay before pulling, then short connect with COM
2. COM1-COM4:relay common interface
3. NC1-NC4: relay normally close interface, short connect the relay with COM before pulling, then suspend