BeagleBone Black Comms Cape

Hello,

I am working on a project with the Beaglebone Black Comms Cape (Link Below). I am having trouble with the 4-20mA input on the AI. When I send a 20mA signal into the input on the BBB reads 0.684. I would assume that 20mA should be = 1.

I am using a 12 VDC 4-20mA signal generator to supply the 4-20mA signal.

Comms Cape Link

Thanks.