Document
TECHNICAL 1 DATA
RELATIVE HUMIDITY MODULE HM 1500
Based on the rugged HS1101 capacitive humidity sensor, HM1500 is a dedicated humidity transducer designed for OEM applications where a reliable and accurate measurement is needed. Direct interface with a micro-controller is made possible with the module’s linear voltage output.
MAIN FEATURES
G G G G G G G G G Small size Not affected by water immersion Full interchangeability High reliability and long term stability Typical 1 to 4 Volt DC output for 0 to 100 % RH at 5 V DC supply Calibrated within +/- 2 % RH @ 55 % RH Very low temperature dependence Ratiometric to voltage supply within the specified range Suitable for 3 to 7 Volts supply voltage
HM 1500
HUMIDITY SENSOR SPECIFIC FEATURES
G G G G Instantaneous de-saturation after long periods in saturation phase. Patented solid polymer structure. High resistance to chemicals. Fast response time.
OPERATING RANGE
100
1
2
MAXIMUM RATINGS
Ratings Symbol Value Unit
RELATIVE HUMIDITY IN %
INTERMITTENT OPERATION 75
ST EA DY
Storage Temperature Supply Voltage (Peak) Humidity Operating Range
Tstg Vs RH
-30 to 70 7 0 to 100 -30 to 60
°C Vdc % RH °C
50
E AT ST
25
Temperature Operating Range Ta
Peak conditions : less than 10% of the operational time.
0 -40
-20
0
20
40
60
80
AMBIENT TEMPERATURE IN °C
CHARACTERISTICS
Characteristics
(Ta = 23°C, Vs = 5Vdc, RL
> 1MΩ otherwise stated)
Symbol Min. Typ. Max. Unit.
Humidity measuring range Relative Humidity accuracy (10 to 95 % RH) Voltage supply Nominal output @ RH = 55 % Current consumption Temperature coefficient (10 to 50 °C ) Averaged Sensitivity from 33% to 75% RH Sink current capability (RL = 15 kΩ) Recovery time after 150 hours of condensation Humidity Hysteresis Long term stability Response time (33 to 76 % RH, static, @ 63 %) Output impedance
RH RH Vs Vout Ic Tcc
1 +/- 3 4.75 2.42 5.00 2.48 0.4 + 0.1 + 25
99 +/- 5 5.25 2.54 0.8
% RH % RH V V mA % RH/°C mV /% RH
∆mV /% RH
Is t
300 10 +/-1.5 0.5
µA s % RH % RH/yr s
τ
Z
10 70
Ω
HPC009 Rev. H October 2001
TECHNICAL 2 DATA
MEASUREMENT CONDITIONS
G HM1500 is specified for accurate measurements within 10 to 95% RH. G Excursion out of this range (< 10% or > 95% RH, including condensation) does not affect the reliability of HM1500 characteristics. G Dedicated HM15XX Product are available for extreme RH conditions (as HM1520 for low dewpoints) Consult HUMIREL for further information.
Output Voltage (mV)
HM 1500 Typical Measuring Ranges in Humidity
4000
HM 1504
3500
3000
METROLOGY HM 1500 RANGE
2500
2000
1500
METROLOGY HM 1520 RANGE
1000 0 10 20 30 40 50 60 70 80 90 100
Relative Humidity in %
HM1500 MODELLED LINEAR VOLTAGE OUTPUT (VS = 5V)
4000
REFERENCE OUTPUT VALUES RH (%) Vout(mV) RH (%) Vout(mV) 1325 10 2480 55 1465 15 2605 60 1600 20 2730 65 1735 25 2860 70 1860 30 2990 75 1990 35 3125 80 2110 40 3260 85 2235 45 3405 90 2360 50 3555 95
3500
Output Voltage (mV)
3000
2500
2000
1500
Vout = 25.68 RH + 1079 from 10 to 95 % RH
with Vout in mV and RH in %
1000 0 10 20 30 40 50 60 70 80 90 100
Relative Humidity in % RH
Reversed Polynomial Equation
Vout = 9E-4RH3 -1.3E-1RH2 + 30.815RH + 1030
ERROR BUDGET AT 23°C
6 5 4
HM1500 ERROR LIMITS
Delta in % RH
3 2 1 0 -1 -2 -3 -4 -5 -6 0 10 20 30 40 50 60 70 80 90 100
Temperature coefficient compensation
RHCor% = RH%
Read
* (1 -(Ta -23)* 2.4E-3)
Relative Humidity in % RH
2 1.5
Non linearity and temperature compensation
RH% = -1.919E-9Vout3 + 1.335E-5Vout2 + 9.607E-3Vout - 21.75
Delta in % RH
1 0.5 0 -0.5 -1 -1.5 -2 0 10 20 30 40 50 60 70 80 90 100
1 + (Ta-23) * 2.4E-3
All equations Vout in mV, RH in %, Ta in °C.
Relative Humidity in % RH
LINEARITY ERROR OF HM1500 MODULE
HPC009 Rev. H October 2001
TECHNICAL 3 DATA
HUMIDITY MEASUREMENT USING HM1500
Typical HM 1500 relative Humidity measurement
100 80
Relative Humidity (% RH)
70
60
50
40
30
% RH = 0.0391 Vout -42.5 from 10 to 95 % RH
20
with Vout in mV and RH in %
10 0 1000 1500 2000 2500 3000 3500 4000
Output Voltage (mV)
Internal block diagram of HM1500
Reference Oscillator L.P. Filter Sensor Oscillator Gain Vout -->
Suggested applications for HM1500 Steps of 1% RH are achievable by using 8-bit A/D. If more resolution is required a 10 -bit A/D needs to be used and a third display will be added, giving steps of 0.2% RH
Read AINO
VCC5
VCC5
U1
3 4 16 15 RTCC MCLR OSC1 OSC2/CLK RA/AIN0 RA/AIN1 RA/AIN2 RA/AIN3 RBO RB1 RB2 RB3 RB4 RB5 RB6 RB7
17 18 1 2
C2
X1
PIC16CXXX With A/D
6 7 8 9 10 11 12 1317
HM150X
C1
VCC5
1 3
Calculate RH% using equation or using alook up table
VI
7805
GND
VO
VCCIN
Convert RH% to BCD code Send data to display
2
HPC009 Rev. H October 2001
TECHNICAL 4 DATA
G RESISTANCE TO PHYSICAL AND CHEMICAL STRESSES - HM1500 has passed through qualification processes of HUMIREL including vibration, shock, storage, high temperature and humidity, ESD. - Additional tests under harsh chemical conditions demonstrate good operation in presence.