Modbus - Trying to read a float from an Energy Meter

[BJM]

Hope you guys can help me. I am trying to read an Energy Meter through ModBus RTU. I am able to read holding registers that are 4x registers, but not the Input registers that are 3x Registers. The instruction says to read the registers in pair to obtain the float value. When trying to read a input register I get an error "Modbus Failure On State sending Get More About It By Logging". I use the Modbus Read note and read e.g. funktion code 4, register 30001, quantity 2.