reading a 32bit value from a modbus slave device using com_mod_mast

I want to read a float value from a mod bus slave device using com_mod_mast.
Is any type casting required to read the value properly in plc, if so then how to do it.
i have defined an array of datatype word of length 2 in the data input of the com_mod_mast block.But Im getting some unknown value of 16828 in the first word of the array while the second word reads zero for a value of 23.5 in the slave device.