Rosemount 2700 - Measurement Units and Sensor Type

A-36
MODEL 2700 APPENDIX A
MODBUS PROTOCOL
Measurement Units, Sensor Type 33-50
Register contents = 16*Unit_Value + Sensor_Type_Value
See Modbus Tables for Unit_Value and Sensor_Type_Value.
For Units and Sensor Type of Primary measurement
Register = 33 + 2*(Sensor_number - 1)
For Units and Sensor Type of Secondary measurement
Register = 34 + 2*(Sensor_number - 1)
Primary Display Source
Register = 49
Dual Units
Register = 50
Example: Read Units and Sensor Type of Primary measurement of Sensor1
Sensor_number = 1
Register = 33
Function Code 04 Read Input Registers
Starting Register 33
Number of Points 01
Register contents in hexadecimal
30033: 0200
Unit_Code = quotient(0200hex/0100hex) = 2
Sensor_Type_Code = remainder(0200hex/0100hex) = 0
From Modbus Tables
Units: µS/cm
Sensor Type: .01/cm
Measurements in Floating-point format 51-84
Measurements are the Primary and Secondary sensor measurements, or a Dual measurement.
Sensor Primary measurement
First Register = 51 + 4*(Sensor_number - 1)
Second Register = 52 + 4*(Sensor_number - 1)
Sensor Secondary measurement
First Register = 53 + 4*(Sensor_number - 1)
Second Register = 54 + 4*(Sensor_number - 1)
Dual measurement
First Register = 83
Second Register = 84
Measurement values are in floating-point format per ANSI/IEEE Standard 754-1985.
measurement value = (-1)^sign * 2^(exponent-127) * 1.mantissa
sign = S00
exponent = E07 E06 E05 E04 E03 E02 E01 E00
antissa = (M22 M21 M20 M19 M18 M17 M16 M15 M14 M13 M12 M11 M10 M09
M08 M07 M06 M05 M04 M03 M02 M01 M00) / 2^23
The data is arranged as follows:
First Register
E00 M22 M21 M20 M19 M18 M17 M16 S00 E07 E06 E05 E04 E03 E02 E01
Second Register
M07 M06 M05 M04 M03 M02 M01 M00 M15 M14 M13 M12 M11 M10 M09 M08