Allen-Bradley 1734-IB4 POINT I/O 4-Channel Sinking Input Module By wayne No Comments on Allen-Bradley 1734-IB4 POINT I/O 4-Channel Sinking Input Module 3 Min Read Procure the Allen-Bradley 1734-IB4 POINT I/O module. This 4-channel DC sinking input module operates at 24VDC for distributed control systems.