Xylem H-3521 - Manual (Page 57)

H-3531
Modbus Protocol B-5
The input registers of the H-3531 FlashLite™ hold the measurement data. When the user sends a
read command to read an input register the register read initiates a measurement sequence and
returns the updated value. Note: The measurement sequence takes approximately 3 seconds to
complete before the requested data is sent. The host must know this so that it does not timeout or
send a retry. These registers are 64-bit floating point (double precision) numbers. Table 3 below
shows the contents of the input register followed by a description of each register.
Table 3 - Input Registers
Info in Register Start Address # of 16bit Registers Data Type
Stage 0 / “0000" 4 IEEE F.P.
Pressure 4 / “0004" 4 IEEE F.P.
Temperature 8 / “0008" 4 IEEE F.P.
Battery Voltage 12 / “000C” 4 IEEE F.P.
Stage 16 / “0010" 2 IEEE F.P.
Pressure 18 / “0012" 2 IEEE F.P.
Temperature 20 / “0014" 2 IEEE F.P.
Battery Voltage 22 / “0016” 2 IEEE F.P.
B.5.0 Stage(RO) This input register holds the current measured stage in the desired
units. As shown in the table you can also read the value as a 32-bit floating point number.
B.5.1 Pressure(RO) This input register holds the current measured pressure before any
slope or offset is applied, therefore it holds the raw psi value. As shown in the table you
can also read the value as a 32-bit floating point number.
B.5.2 Temperature(RO) This input register holds the current measured temperature.
This temperature reading is the temperature of the internal pressure sensor and may not
accurately reflect air temperature. As shown in the table you can also read the value as a
32-bit floating point number.
B.5.3 Battery Voltage(RO) This input register holds the current input voltage. As
shown in the table you can also read the value as a 32-bit floating point number.