Thank you for your post.
It is possible to measure 4-20mA with our equipment. This can be achieved by using a shunt resistor between gnd and channel. The software can the use scaling files to convert it to a pressure unit. I would recommend that you look at the ADC-11/12, this is an 11 channel unit, 12 bits of resolution. There is also a terminal board available with screw terminals to make connecting your cables easier. The shunt resistor can also be placed onto the terminal board.
Unfortunately, I am not familiar with SCADA systems, but our software does not link with other systems. The ADC-11 has to be connected to a PC at all times and the software needs to be running at all times whilst in use.
It is possible to use the drivers to write your own software if you wished to go down this route.