Specifications - HMT370EX

Table 1. Measurement performance
Property	Description/value
Relative humidity
Measurement range	0 … 100 %RH
Accuracy at +23 °C (+73.4 °F) ¹	±0.8 %RH (0 … 90 %RH)
Factory calibration uncertainty ²	±0.5 %RH (0 … 40 %RH) ±0.8 %RH (40 … 95 %RH)
T₆₃ response time	15 s
Sensor options	HUMICAP® R2 HUMICAP® L2
Temperature
Measurement range	−70 … +180 °C (−94 … +356 °F)
Accuracy at +23 °C (+73.4 °F) ¹	±0.1 °C (±0.18 °F)
Factory calibration uncertainty ²	±0.1 °C (±0.18 °F) at +23 °C (+73.4 °F)
Sensor	Pt1000 RTD Class F0.1 IEC 60751
Other available measurement parameters
Dew point temperature, dew point / frost point temperature, absolute humidity, mixing ratio, wet-bulb temperature, water concentration, water vapor pressure, water vapor saturation pressure, enthalpy, dew point temperature difference, absolute humidity at NTP, water mass fraction, relative saturation, water activity, water concentration in mineral transformer oil, water concentration in JET A-1 fuel, saturation temperature

Figure 1. Humidity measurement accuracy as function of temperature

Figure 2. Temperature measurement accuracy over full range

HUMICAP® 180L2 sensor option

The HUMICAP® 180L2 sensor is used in the HMP378F and HMP378H probe variants that are intended for oil and JET A-1 fuel measurements.

Table 2. HUMICAP® 180L2 measurement performance
Property	Description/value
Water activity
Measurement range	0 … 1 a_w ¹
T₉₀ response time ²	10 min
Sensor	HUMICAP® 180L2
Accuracy ³	±0.01 a_w (±1 %RS)
Factory calibration uncertainty	±0.6 %RH (0 … 40 %RH) ±1.0 %RH (40 … 95 %RH)
Temperature
Measurement range	−40 … +180 °C (−40 … +356 °F)
Accuracy at +20 °C (+68 °F)	±0.2 °C (0.36 °F)

Table 3. HMP378F and HMP378H ppm accuracy
Property	Value
JET A-1 fuel ppm accuracy (HMP378H) ⁶	±15 % of the reading (typical)
Moisture in transformer oil ppm accuracy (HMP378F) ⁷	±10 % of the reading (typical)

Table 4. Operating environment
Property	Description/value
Operating temperature for electronics	-40 … +60 °C (-40 … +140 °F)
Operating temperature with display	-20 … +60 °C (-4 … +140 °F)
Storage temperature	-40 … +70 °C (-40 … +158 °F)
Pressure range	See probe specifications
Note: Do not install the LCD display model in a location where the transmitter is exposed to direct sunlight.

Table 5. Compliance
Property	Description/value
Electromagnetic compatibility (EMC)	EN 61326‑1, industrial environment
Compliance marks	CE, China RoHS, RCM

Table 6. Inputs and outputs
Property	Description/value
Operating voltage	12 … 28 V
Analog outputs	2 outputs (two-wire, 4 … 20 mA) Connection via safety barriers
Typical accuracy of analog outputs at +20 °C	±0.0625 % full scale
Typical temperature dependence of analog outputs	0.005 % / °C (0.005 % / °F) full scale
Transmitter service port connection	USB cable 219690
Probe service port connection	USB cable USB2
Display options	Graphical LCD display Model without display ⁸

Table 7. Mechanical specifications
Property	Description/value
Connections	Screw terminals, 0.33 … 2.0 mm² wires (AWG 14-22)
Cable glands	M20×1.5
Conduit fitting	NPT 1/2" and M16
Housing material	EN AW-6082
Housing weight	LCD transmitter: 1500 g (3.3 lb) LED transmitter: 1520 g (3.35 lb) HMP371 fixed probe: 320 g (0.7 lb)
IP rating	Non-explosive atmospheres, with probe connected to the transmitter body: IP66
IP rating	Explosive atmospheres (see detailed information in the applicable Ex certificate): IP54
UL 50E (NEMA) rating	Type 4: Dust-tight. Protected from powerful water jets from any direction.

Figure 4. HMT370EX transmitter dimensions

Table 8. Ex classifications by region
Property	Description/value
NOTE: The Ex classifications show the highest level of compliance. Although lower compliance levels are not shown in the classification, they are also included in the classification. For example, compliance with Division 1 also means compliance with Division 2, and compliance with Zone 0 also means compliance with Zone 1 and Zone 2.
Europe (ATEX)
Gas classification EU (2014/34/EU)	II 1 G Ex ia IIC T4 Ga
Dust classification	II 1 D Ex ia IIIC T₂₀₀ 85 °C Da
Safety factors	U_i = 28 VDC, I_i = 100 mA, C_i = 12.1 nF, P_i = 700 mW, L_i = 16 μH
Environmental specifications
T_amb	-40 … +60 °C (-40 … +140 °F)
P_amb	0.8 … 1.1 bar
International (IECEx)
Gas classification	Ex ia IIC T4 Ga
Dust classification	II 1 D Ex ia IIIC T₂₀₀ 85 °C Da
Safety factors	U_i = 28 VDC, I_i = 100 mA, C_i = 12.1 nF, P_i = 700 mW, L_i = 16 μH
Environmental specifications
T_amb	-40 … +60 °C (-40 … +140 °F)
P_amb	0.8 … 1.1 bar
Japan (CML)
Ex classification	Ex ia IIC T4 Ga Ex ia IIIC T₂₀₀ 85°C Da CML 21JPN2417X
China (NEPSI)
Ex classification	Ex ia IIC T3~T6 Ga GYJ21.1325X
Korea (KCs)
Ex classification	Ex ia IIC T4 Ga Ex ia IIIC T200 85 °C Da -40 °C ≤ Tamb ≤ +60 °C IECEx EESF 20.0044.X 21-KA4BO-0891X, 21-KA4BO-0892X
US (FM)
Ex classification	Class I, Zone 0, AEx ia IIC T4 Ga Zone 20, AEx ia IIIC T85°C Da IS Class I, Division 1, Groups A, B, C, and D T4 IS Class II, III, Division 1, Groups E, F, and G T85°C
US/CAN (MET)
Ex classification	Class I, Zone 0, AEx ia IIC T4 Ga Class II, Zone 20, AEx ia IIIC T 85°C Da Class I, Division 1, Groups A, B, C, and D T4 Class II, Division 1, Groups E, F, and G T 85 °C Ex ia IIC T4 Ga Ex ia IIIC T 85 °C Da
UK (UKEX)
Ex classification	II 1 G Ex ia IIC T4 Ga II 1 D Ex ia IIIC T200 85 °C Da −40 °C ≤ Tamb ≤ +60 °C CML 21UKEX2316X
Canada (CSA)
Ex classification	Ex ia IIC T4 Ga Ex ia IIIC T85°C Da IS Class I, Division 1, Groups A, B, C, and D T4 Class II, III, Division 1, Groups E, F, and G

¹ Defined against calibration reference. Including non-linearity, hysteresis, and repeatability.

² Defined as ±2 standard deviation limits. Small variations possible; see calibration certificate.

³ 0 … 1 a_w corresponds to 0 … 100 %RH

⁴ At +20 °C (+68 °F) in still oil.

⁵ In range 0 … 0.5 a_w, including non-linearity, hysteresis, and repeatability. See accuracy graph below.

⁶ For more information on HMP378H measurements, see HMP378H probe option for measuring JET A-1 fuel moisture and temperature

⁷ Note: valid for mineral transformer oil. For more information on HMP378F measurements, see HMP378F probe option for measuring oil moisture and temperature

⁸ Recommended when the transmitter is exposed to direct UV light, and for outdoor installations and high-humidity environments.