Allen-Bradley 1746-IV16 SLC 500 Sourcing Input Module By wayne No Comments on Allen-Bradley 1746-IV16 SLC 500 Sourcing Input Module 2 Min Read Buy the Allen-Bradley 1746-IV16 SLC 500 discrete input module. This 16-channel sourcing module works with 24VDC and offers a wide 10-30VDC range.