My experience of getting data out of simple equipment via RS-232 is you send it a code effectively saying "what is XXXXX (the parameter you want)?" and it returns a number which sometimes needs decoding.
I am afraid without the manual and these codes you have little chance.
LabView is very good at getting data and then displaying it. But pricy.
Robert

My spelling is not bad. I am typing this on a Medigenic keyboard and I blame that for all my typos.