rtu resolution

I'm planning on using an RTU to transmit the level on a water tower. The RTU states it has an 8 bit resolution. I want to measure 0-30' by feeding a 4-20 signal into the RTU. Should I be able to get a resolution of approx. 1.5"?(30'x12"/255) I'm just wondering if I am understanding this correctly.
Thanks

Assuming your RTU is using an UNSIGNED 8 bit number, you're right. You'll get a resolution of 30' / 255, which is about 1.4" if my calculator skills are still sharp this time of night.

AK