For Configuring a DP Flow Transmitter, we have to enter two ranges in the flow transmitter using HART communication.
First Range : Pressure Range or mmWC range
Second Range : Flow Transmitter OUT scale, which is in m3/hr, kg,hr, ton/hr like that as per need.
So as it is a DP flow transmitter, some pressure difference will be measured (in units like mmWC) and then flow transmitter automatically converts this mmWC measured value into respective Flow value units like m3/hr, ton/hr like that. The scaling/conversion depends on the ranges of first range - mmWC and second range Flow meter out scale.
Yes, you can use DP flow transmitter for level measurement.
Note : For every level transmitter (DP type) we calculate the mmWC or pressure based on installation, so with 100% level some pressure value will be calculated say 2500 mmWC pressure 100% level in a vessel. Every DP type transmitter have some mmWC range say - 5000 mmWC to +5000 mmWC, so inorder to use a DP flow transmitter, your calculated mmWC at 100% level i.e. in our example which is 2500mWC value must be within the DP Flow transmitter mmWC scale.