Vaisala HUMICAP HMM170 - Modbus Communication Examples

Register
number
Address Register description Data format Unit
278 0115
hex
Water concentration (wet
basis)
16-bit signed
integer
vol-% * 100
279 0116
hex
Relative humidity (dew/frost) 16-bit signed
integer
%RH * 100
289 0120
hex
Water mass fraction 16-bit signed
integer
ppm
w
A.4.2 Configuration registers
Table 20 Modbus configuration data registers (writable)
Register
number
Register
address
Register description Data format Unit / Valid range
General
1287 0506
hex
Extra heat on/o. Enables
heating of humidity sensor
when close to saturation.
Measurement is disabled for
the duration of heating and
cooling.
16-bit boolean 0 = O (default)
1 = On
1289 0508
hex
Probe heating on/o.
When on, output parameters
that depend on temperature
measurement (for example,
relative humidity) are
disabled unless temperature
is written to register 0334
hex
from an external source.
16-bit boolean 0 = O
1 = On
Appendix A – Modbus reference
37