Sensors - How to convert 4-20mA output to temperature and pressure values?
You need to search for a better data sheet such as this one for the OS136A.

So, for the OS136-1 device, 4 mA represents 0 degF and 20 mA represents 400 degF. You can assume that the reading will be linear between these two points but, if in doubt, contact their sales team.
Here's the PDF for the pressure sensor so I'd tak a look through it to check.