Analog Inputs?

I am using two 1734-IE2V cards on an AB PointIO for a 0-10V input from a potentiometer. When I connect one single potentiometer to the first card, The reference works correct. When I connect another potentiometer, the reference drops significantly on both inputs. It drops each additional potentiometer that I connect. I am using 4 conductor shielded cable and I have tried to ground the shield on one end, then both ends, then isolated. I have exhausted every combination that I can think of, so any help would be greatly appreciated.

Assuming you are wiring it correctly to http://samplecode.rockwellautomation.com/idc/groups/literature/documents/in/1734-in027_-en-e.pdf.

Have you checked the voltage to verify it actually dropped when you connect additional input? Put up a drawing of your wiring diagram.

How much current are you drawing through your potentiometers? What is the resistance of your potentiometers, are you dragging the voltage of your 10Volt power supply down from drawing too much current through your pots? Check the voltage like "harryting" suggested and it may reveal your problem.