Ken,
1.2 Amps, I've been looking at a KFD2-SL-4 from Pepperl and Fuchs. My thinking, if I can parallel the circuits to share the amperage. I cannot get a reply back from them. May have to just buy one and try it.
First of all, the KFD2-SL-4 is not intrinsically safe. So there's that... you can tell because the field terminals aren't blue (which is standard across several brands). The proof of it being IS is a certificate telling this to you. As you can see, no such certificate exists for this model.
The intrinsically safe barriers are also limited in current and will not power this power supply of yours.
Now for your problem...
Your HMI will have something stating its protection method such as Ex e, Ex nA, Ex nR, etc... that tells you the protection method and how to get it connected. Additionally, it will have a certificate number and in it there will be more information that you must follow to install said equipment.
Since that rating is equivalent to ATEX Zone 2, I'm going to say it is Ex nA or Ex e. With this type of protection, you must route your power with a SWA cable and land it with the right gland (if it's Ex e box, then it's going to be an Ex de gland). Ex nA will likely have similar requirement on the glanding.
The cable with the power, however, must not go through a zone 1 or zone 0 or whatever the equivalent is in the US.
Sorry to disagree with you, but the hmi panel must be purged or pressurized, otherwise it must be the nema 7/9 bulky enclosure.
If that is the case, the HMI would have that specified in its IECEX rating as Ex p... for that area, I doubt that it is Ex p and as such that it requires purging or pressurisation. Hopefully op can enlighten us with the model number.