HTM2500LF – Temperature and Relative Humidity Module
•
Hermetic Housing
•
Humidity calibrated within +/-2% @55%RH
•
Temperature measurement through NTC
10kOhms +/-1% direct output
•
Small size product
•
Typical 1 to 4 Volt DC output for 0 to 100%RH
at 5Vdc
DESCRIPTION
Based on the rugged HTS2035SMD humidity / temperature sensor, HTM2500LF is a dedicated humidity and
temperature 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 humidity linear voltage output.
FEATURES
•
Full interchangeability
•
High reliability and long term stability
•
Not affected by water immersion
•
Ratiometric to voltage supply
•
Suitable for 3 to 10 Vdc supply
voltage
Humidity Sensor Specific Features
• Instantaneous de-saturation after long periods in saturation
phase
• Fast response time
• High resistance to chemicals
• Patented solid polymer structure
Temperature Sensor Specific Features
• Stable
• High sensitivity
APPLICATIONS
•
•
•
•
…
Industrial
Process control
Hygrostat
Data logger
HTM2500LF HPC169 Rev C
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1/9
October 2012
HTM2500LF – Temperature and Relative Humidity Module
PERFORMANCE SPECS
MAXIMUM RATINGS
Ratings
Storage Temperature
Storage Humidity
Supply Voltage (Peak)
Humidity Operating Range
Temperature Operating Range
Symbol
Tstg
RHstg
Vs
RH
Ta
Value
-40 to 85
0 to 100
12
0 to 100
-40 to 85
Unit
°C
% RH
Vdc
% RH
°C
Peak conditions: less than 10% of the operating time
ELECTRICAL CHARACTERISTICS
(Ta=23°C, Vs=5Vdc +/-5%, R L>1MΩ unless otherwise stated)
Humidity Characteristics
Humidity Measuring Range
Relative Humidity Accuracy (10 to 95% RH)
Supply Voltage
Nominal Output @55%RH (at 5Vdc)
Current consumption
Temperature Coefficient (10 to 50°C)
Average Sensitivity from 33% to 75%RH
Sink Current Capability (RL=15kΩ)
Recovery time after 150 hours of condensation
Humidity Hysteresis
Long term stability
(1)
Time Constant (at 63% of signal, static) 33% to 76%RH
Output Impedance
(1)
Symbol
RH
RH
Vs
Vout
Ic
Tcc
∆Vout/∆RH
Is
tr
Min
1
4.75
2.42
Typ
+/-3
5.00
2.48
1.0
+0.1
+26
Max
99
+/-5
5.25
2.54
1.2
Unit
%RH
%RH
Vdc
V
mA
%RH/°C
mV/%RH
µA
s
%RH
%RH/yr
s
Ω
300
10
+/-1.5
+/-0.5
5
70
T
τ
Z
At 1m/s air flow
(Ta=25°C)
Temperature Characteristics
Nominal Resistance @25°C
Beta value: B25/50
Temperature Measuring Range*
Nominal Resistance Tolerance @25°C
Beta Value Tolerance
Response Time
Symbol
R
β
Ta
RN
β
τ
Min
3347
-40
Typ
10
3380
Max
Unit
kΩ
K
°C
%
%
s
3413
85
1
1
10
* For temperature upper than 60°C, specific high te mperature cable is required: HTM2500LFL products
HTM2500LF HPC169 Rev C
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2/9
October 2012
HTM2500LF – Temperature and Relative Humidity Module
TYPICAL PERFORMANCE CURVES
HUMIDITY SENSOR
•
Typical response look-up table (Vs = 5V)
RH (%)
10
15
20
25
30
35
40
45
50
•
Vout (mV)
1235
1390
1540
1685
1825
1960
2090
2220
2350
RH (%)
55
60
65
70
75
80
85
90
95
Vout (mV)
2480
2605
2730
2860
2990
3125
3260
3405
3555
Modeled linear voltage output (Vs = 5V)
4000
100
Relative Humidity (%RH)
Output Voltage (mV)
90
3500
3000
2500
2000
1500
80
70
60
50
40
30
20
10
1000
0
0
10
20
30
40
50
60
70
80
90
100
1000
1500
Relative Humidity (%RH)
•
2000
2500
3000
3500
4000
Output Voltage (mV)
Linear Equations
Vout = 26.65 * RH + 1006
RH = 0.0375 * Vout – 37.7
with Vout in mV and RH in %
•
Polynomial Equations
-3
3
-1
2
Vout = 1.05E * RH - 1.76E * RH + 35.2 * RH + 898.6
-9
3
-5
2
-3
RH = -1.92E * Vout + 1.44E * Vout + 3.4E * Vout – 12.4
with Vout in mV and RH in %
•
Measurement Conditions
HTM2500LF is specified for accurate measurements within 10 to 95% RH.
Excursion out of this range (95% RH, including condensation) does not affect the reliability of
HTM2500LF characteristics.
HTM2500LF HPC169 Rev C
www.meas-spec.com
3/9
October 2012
HTM2500LF – Temperature and Relative Humidity Module
•
Error Budget at 23°C
HTM2500LF Error Limits:
Temperature coefficient compensation:
RH
Cor
(
% = RH read % × 1 − (T a − 23)× 2.4 E
−3
)
HTM2500LF Linearity Error:
Non-linearity and temperature compensation:
2
− 1.9206 E −9 V out + 1.437 E −5 Vout + 3.421 E −3 V
− 12.4
out
RH % =
1 + (T a − 23) × 2.4 E −3
3
with Vout in mV, RH in % and Ta in °C
HTM2500LF HPC169 Rev C
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4/9
October 2012
HTM2500LF – Temperature and Relative Humidity Module
HTM2500LF TEMPERATURE SENSOR: DIRECT NTC OUTPUT
•
Typical temperature output
Depending on the needed temperature measurement range and associated accuracy, we suggest two methods
to access to the NTC resistance values.
RT = RN × e
RT
RN
T, TN
β
e
1 1
T TN
β −
NTC resistance in Ω at temperature T in K
NTC resistance in Ω at rated temperature T in K
Temperature in K
Beta value, material specific constant of NTC
Base of natural logarithm (e=2.71828)
The exponential relation only roughly describes the actual characteristic of an NTC thermistor can, however,
the material parameter β in reality also depend on temperature. So this approach is suitable for describing a
restricted range around the rated temperature or resistance with sufficient accuracy.
For practical applications, a more precise description of the real R/T curve may be required. Either more
complicated approaches (e.g. the Steinhart-Hart equation) are used or the resistance/temperature relation as
given in tabulation form. The below table has been experimentally determined with utmost accuracy for
temperature increments of 1 degree.
Actual values may also be influenced by inherent self-heating properties of NTCs. Please refer to MEAS-France
Application Note HPC106 “Low power NTC measurement”.
•
Temperature look-up table
Temp (°C)
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
20
HTM2500LF HPC169 Rev C
R (Ω)
195652
148171
113347
87559
68237
53650
42506
33892
27219
22021
17926
14674
12081
Temp (°C)
25
30
35
40
45
50
55
60
65
70
75
80
85
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5/9
R (Ω)
10000
8315
6948
5834
4917
4161
3535
3014
2586
2228
1925
1669
1452
October 2012
HTM2500LF – Temperature and Relative Humidity Module
•
Steinhart-Hart coefficients
According to the equation below, the Steinhart-Hart coefficients for the operating temperature range for
HTM2500LF thermistor are:
1
= a + b * ln( R ) + C * ln( R) * ln( R ) * ln( R)
T
NTC resistance in Ω at temperature T in K
Temperature in K
Constant value (a = 8.54942E-04)
Constant value (b = 2.57305E-04)
Constant value (c = 1.65368E-07)
R
T
a
b
c
•
Temperature Interface Circuit
Concerning the temperature sensor of the HTM2500LF, the following measuring method described below is
based on a voltage bridge divider circuit. It uses only one resistor component (Rbatch) at 1% to design
HTM2500LF temperature sensor interfacing circuit.
Rbatch is chosen to be equal to NTC @25°C to get: V out = Vcc/2 @25°C.
The proposal method connects Rbatch to Vcc (5Vdc) and NTC to Ground. It leads to a negative slope
characteristic (Pull-Up Configuration).
VOUT (mV ) =
W2
VCC
Temp (°C)
R ( Ω)
-40
-30
-20
-10
0
10
20
25
30
40
50
60
70
80
195652
113347
68237
42506
27219
17926
12081
10000
8315
5834
4161
3014
2228
1669
Rbatch
10kΩ
W4
NTC Resistance output
HTM2500LF NTC
10kΩ @25°C
Vout (mV)
W1
Ground
HTM2500LF HPC169 Rev C
Vcc(mV ) * NTC HTM 2500LF (Ω)
Rbatch (Ω) + NTC HTM 2500LF (Ω)
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6/9
Pull-up Configuration
Vout (mV)
4757
4595
4361
4048
3657
3210
2736
2500
2270
1842
1469
1158
911
715
October 2012
HTM2500LF – Temperature and Relative Humidity Module
SUGGESTED APPLICATION
Steps of 1% RH are achievable by
using 8-bit A/D.
If more resolution is required, a 10bit A/D needs to be used and a third
display will be added, giving steps of
0.2% RH.
QUALIFICATION PROCESS
RESISTANCE TO PHYSICAL AND CHEMICAL STRESSES
•
•
•
HTM2500LF has passed through qualification processes of MEAS-France including vibration, shock,
storage, high temperature and humidity, ESD.
Additional tests under harsh chemical conditions demonstrate good operation in presence of salt
atmosphere, SO2 (0.5%, H2S (0.5%), 03, NOx, NO, CO, CO2, Softener, Soap, Toluene, acids (H2SO4,
HNO3, HCI), HMDS, Insecticide, Cigarette smoke, this is not an exhaustive list.
HTM2500LF is not light sensitive.
SPECIFIC PRECAUTIONS
•
•
HTM2500LF is not protected against reversed polarity - Check carefully when connecting the device.
If you wish to use HTM2500LF in a chemical atmosphere not listed above, consult us.
HTM2500LF HPC169 Rev C
www.meas-spec.com
7/9
October 2012
HTM2500LF – Temperature and Relative Humidity Module
PACKAGE OUTLINE
Dim
Min (mm)
Max (mm)
A
53
55
B
74.3
76.3
C
11.2
11.6
200
250
1450
1550
D*
(HTM2500LF)
D*
(HTM2500LFL)
*Specific length available on request
For operating temperature upper than 60°C, specific high temperature
cable is required (1500mm long)
Wire
Cable Color
HTM2500LF
Cable Color
HTM2500LFL
W1
Brown
Black
W2
White
Orange
Supply Voltage
W3
Yellow
Yellow
Humidity Voltage Output
W4
Green
Purple
Temperature Output
(NTC Direct)
W5
Black (thick)
Black (thick)
Function
Ground
Shield
HTM2500LF weight: 17.5g
HTM2500LFL weight: 50g
HTM2500LF wire characteristics: AWG 24 for W1, W2, W3 and W4 / AWG 16 for W5
HTM2500LFL wire characteristics: AWG 24 for W1, W2, W3 and W4 / AWG 16 for W5
HTM2500LF HPC169 Rev C
www.meas-spec.com
8/9
October 2012
HTM2500LF – Temperature and Relative Humidity Module
ORDERING INFORMATION
HPP809A031 : HTM2500LF
HUMIDITY VOLTAGE OUTPUT + NTC (TEMPERATURE DIRECT OUTPUT)
HPP809A033 : HTM2500LFL
HUMIDITY VOLTAGE OUTPUT + NTC (TEMPERATURE DIRECT OUTPUT) WITH LONG CABLE
(MULTIPLE PACKAGE QUANTITY OF 10 PIECES)
Customer Service contact details
Measurement Specialties, Inc - MEAS France
Impasse Jeanne Benozzi
CS 83 163
31027 Toulouse Cedex 3
FRANCE
Tél: +33 (0)5 820 822 02
Fax: +33(0)5 820 821 51
Sales: humidity.sales@meas-spec.com
Revision
0
A
B
C
Comments
Document creation
Temperature operating range updated, HTM25X0LFL
references added
New MEAS template, Temperature operating range
updated, RH polynomial equation modified, package
outline paragraph updated
New combined RH/Temp sensor implemented,
HTM2530LF product reference deleted
Who
D. LE GALL
Date
July 09
D. LE GALL
December 09
D. LE GALL
January 12
D. LE GALL
October 12
The information in this sheet has been carefully reviewed and is believed to be accurate; however, no responsibility is assumed for
inaccuracies. Furthermore, this information does not convey to the purchaser of such devices any license under the patent rights to the
manufacturer. Measurement Specialties, Inc. reserves the right to make changes without further notice to any product herein. Measurement
Specialties, Inc. makes no warranty, representation or guarantee regarding the suitability of its product for any particular purpose, nor does
Measurement Specialties, Inc. assume any liability arising out of the application or use of any product or circuit and specifically disclaims
any and all liability, including without limitation consequential or incidental damages. Typical parameters can and do vary in different
applications. All operating parameters must be validated for each customer application by customer’s technical experts. Measurement
Specialties, Inc. does not convey any license under its patent rights nor the rights of others.
HTM2500LF HPC169 Rev C
www.meas-spec.com
9/9
October 2012