Allen-Bradley 1746-IV8 SLC 500 24VDC Sourcing Input Module By wayne No Comments on Allen-Bradley 1746-IV8 SLC 500 24VDC Sourcing Input Module 3 Min Read The Allen-Bradley 1746-IV8 offers eight 24VDC sourcing inputs for your SLC 500 system. It features an 8ms signal delay and a 10-30VDC range.