1756-IF16 Issues

I have a two 1756-IF16 in a 17 card chassis with a L72 processor. I have the cards configured for 0-20 mA, low raw 4 mA, High raw 20 mA, low EU 4000 and high EU 20000. All of the inputs on this card are configured the exact same and are all reading the exact same number. It is just about 0 mA, but very slightly above. The electricians have measured 4 mA coming into the cards inputs. I am at a loss on what could be causing this and looking for any kind of ideas. I believe that there are possible wiring issues going to the car being as this is a brand new panel, but not certain.

Single-ended

are you using differential or single ended inputs?

sorry, is the sensor a source or sink? can you show me how it is wired? what kind and model of transducer do you have connected to the inputs

+24 VDC going out to the sensor on the white wire off of the power distribution. The signal comes back on black, which ties into the analog input. And the ground wire is tied to ground.

all of the RTN's on the right side of the terminal block on the card are tied to -24 VDC. But from what I remember, any of the RTN's on the left side of the terminal block (side with inputs) aren't tied into anything.

look at the drawing, you must have a complete circuit. i RTN0,1,2,3 etc must all connect to the sensor ground and the corresponding RTN terminal. It sounds as though you may have a 3 wire trasnducer, and you may have to use differential type inputs. see page 69 through 72 of the following manual

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1756-um009_-en-p.pdf