Post your program so we can see how the card is configured. If you have more then one card tell us which one it is and tell us which channel it is.
Its .rsp file , zip it first.
If the card is configured for 0-4095 and your analog input is scaled 4-20ma = 0-300
then a 50 PSI input should give you about 683 counts (raw data value)
The card may not be configured for 0-4095.
Have you verified the milliamp signal is correct? Can you tell us what it is ? And what the raw data value is (N10:4)