8
User Manual EE072 Humidity and Temperature Probe with Modbus RTU
Communication settings (INTEGER 16 bit)
Parameter
Register number
1)
[DEC]
Protocol address
2)
[HEX]
Write register: function code 0x06
Slave-ID Modbus address
0001
0x00
Modbus protocol settings
3)
0002
0x01
1) Register number starts from 1.
2) Protocol address starts from 0.
3) For Modbus protocol settings see Application Note Modbus AN0103 (available on
).
INFO (read register)
Parameter
Register number
1)
[DEC]
Protocol address
2)
[HEX]
Read register: function code 0x03 / 0x04
Serial number (as ASCII)
0001
0x00
Firmware version
0009
0x08
Sensor Name
0010
0x09
1) Register number starts from 1.
2) Protocol address starts from 0.
Air pressure
Parameter
Register number
1)
[DEC]
Register address
2)
[HEX]
Read and write register: function code 0x03 / 0x10
Air pressure
3)
5001
0x1388
1) Register number starts from 1
2) Register address starts from 0
3) Ambient pressure in mbar, with 2 decimal digits (e.g. 1008.25), (Default value 1013.25 mbar)
5.2 Modbus Register Map
The measured data is saved as a 32 bit floating point values (data type FLOAT) and as 16 bit signed
integer values (data type INTEGER).
FLOAT (read register):
Parameter name
Unit
Register number
1)
[Dec]
Register address
2)
[HEX]
Read register: function code 0x03 / 0x04
Temperature T
°C
1003
0x3EA
Temperature T
°F
1005
0x3EC
Temperature T
°K
1009
0x3F0
Relative humidity RH, Uw
% RH
1021
0x3FC
Water vapour partial pressure e
mbar
1101
0x44C
Water vapour partial pressure e
psi
1103
0x44E
Dew point temperature Td
°C
1105
0x450
Dew point temperature Td
°F
1107
0x452
Dew point temperature Td
°K
1147
0x47A
Wet bulb temperature Tw
°C
1109
0x454
Wet bulb temperature Tw
°F
1111
0x456
Wet bulb temperature Tw
°K
1145
0x478
Absolute humidity dv
g/m³
1113
0x458
Absolute humidity dv
gr/ft³
1115
0x45A
Mixing ratio r
g/kg
1121
0x460
Mixing ratio r
g/lb
1123
0x462
Specific enthalpy h
kJ/kg
1125
0x464
Specific enthalpy h
ft lbf/lb/kg
1127
0x466
Specific enthalpy h
BTU/lb
1129
0x468
Frost point temperature Tf
°C
1131
0x46A
Frost point temperature Tf
°F
1133
0x46C
Frost point temperature Tf
°K
1149
0x47C
Ice bulb temperature Ti
°C
1237
0x4D4
Ice bulb temperature Ti
°F
1239
0x4D6
Ice bulb temperature Ti
°K
1241
0x4D8
1) Register number starts from 1
2) Register address starts from 0
