Vaisala HMP4 - Output Parameters; Table 3 Availability of Output Parameters

• Sensor purge provides superior chemical resistance (HMP models only)
• Condensation prevention feature minimizes condensation on probe (HMP models with
composite sensors only)
• Traceable calibration certificate:
• HMP and MMP models: 6 points for humidity, 1 point for temperature
• TMP1: 2 points for temperature
• Standalone Modbusâ RTU over RS-485
• Compatible with Indigo series of transmitters
• Can be connected to Vaisala Insight PC software for configuration, calibration,
diagnostics, and temporary online monitoring
2.3 Output parameters
On HMP probe models, the values of all available output parameters are locked
when the sensor is being warmed by the chemical purge function.
Output parameter is available on this model.
Output parameter is available on this model, but its value is unavailable when
condensation prevention functions are warming the sensor. Writing temperature to
Modbus register 0334
hex
from an external source makes the output value available during
condensation prevention.
Output parameter is not available on this model.
Table 3 Availability of output parameters
Output parameter Output unit HMP1, 3, 4, 5,
7, 8, and 9
MMP8 TMP1
Absolute humidity
g/m
3
Absolute humidity at NTP
g/m
3
Dew/frost point temperature °C
Dew/frost point temperature at 1 atm °C
Dew point temperature °C
Dew point temperature at 1 atm °C
Dew point temperature dierence °C
Enthalpy kJ/kg
Mixing ratio g/kg
Relative humidity %RH
Relative humidity (dew/frost) %RH
Relative saturation %RS
Chapter 2 – Product overview
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