Advice re. 4-20mA signal readouts
All the pressure sensor is going to do is send you a signal from 4mA to 20mA in which 4mA represents (usually) the lower limit of its sensing range and 20mA represents the upper limit. I don't think your Hobo unit will be able to log the output of the sensor, since it doesn't seem to have an input for an external sensor. It just logs temperature and humidity using sensors built into it. But there are a lot of data loggers available that could just plug into the sensor. Like this one. I suspect that this one would just log the current reading; there may be others that will let you define how the 4-20mA range maps to whatever units you are actually measuring.