Download EWHS 300/310 Humidity Sensors

EWHS 300/310
Humidity Sensors
Technical Data Sheet
GENERAL DESCRIPTION
The humidity sensors of the EWHS
300/310 series are designed to be
connected to high-accuracy humidity
and humidity/temperature measuring devices. The EWHS 300 is a humidity
measuring device (output signal 4...20
mA) while the EWHS 310 is a humidity
and temperature measuring device (two
0...20 mA outputs).
INSTALLATION
do not cause any mechanical stress to
the sensors and absolutely avoid
touching the humidity sensor.
Use a suitable cable gland to make the
cable exit and connect it to the terminals
according to the instructions shown on
the label located on the inner side of the
cover and on the printed circuit.
Humidity and/or temperature reading
errors can occur if settling time is too
short, or be caused by steam, sprayed
water, air drafts, direct exposure to
sunlight, presence of condensate on the
sensor, or by mounting the device on a
wall cooled by the outside temperature;
the sensor should be installed in such a
way that it is protected against any
possible external factors.
To obtain highly accurate measurements,
the sensor should be left to settle in the
existing atmosphere for some time. Since
the sensor has a mass which affects the
measurement, such "settling time"
should be allowed especially when the
sensor is exposed to a temperature jump.
Condensate may form on the humidity
sensor when there is a quick variation of
temperature and the atmosphere goes
from a low temperature value (cold
sensor) to a high one.
CONNECTION
DIAGRAMS
EWHS 300
There are two slots on the outer side of
the enclosure to mount the device on
the wall by using suitable screws and
anchors. To access the terminal block,
remove the cover by unscrewing the two
screws on it.
Avoid touching any
electronic components. Should it be
necessary to remove the protective cap,
KEY
A
B
Humidity
Supply voltage
EWHS 310
KEY
A
B
C
D
Temperature T
Humidity RH
Ground GND
Supply voltage V+
CONDITIONS OF USE
INTENDED USE
For safety reasons, the control device
shall be installed and used in accordance
with the instructions supplied. The
device must be protected from water
and dust according to the application.
DISALLOWED USE
Any use different from the intended one
is prohibited. We point out that this
sensor provides only a functional
measurement, cannot be considered as a
safety device, and is subject to failure.
Any protection devices required by the
regulations applicable to the product or
suggested by common sense due to
obvious safety requirements must
therefore be carried out in a different
way.
RESPONSABILITY AND RESIDUAL
RISKS
TECHNICAL DATA
Invensys Controls Italy s.r.l. is not
liable for any damage due to:
- installation/use other than specified
and, in particular, differing from the
safety specifications of the legal
regulations and/or supplied with the
present handbook;
- protection against electrical shocks,
water and dust under the effected
installation conditions;
-use on electrical panels permitting
access to dangerous parts without use of
tools.
-tampering with and/or alteration of the
product;
-installation/use
in
panels
not
conforming to standards and regulations
of current laws.
Protection rating: IP65
Mounting: through two external slots
Electrical connections: screw terminals
Dimensions (mm): 80X80X52
Power supply: 9…30 Vc
Power input:
•
EWHS 300: 20mA max
•
EWHS 310: 50mA max.
Ambient temperature: -30° (-22°F) to
+70°C (158°F)
Ambient humidity: 0…100% RH
Humidity sensor: capacitive
Temperature sensor (EWHS 310 only):
Pt100B
Temperature measurement range (EWHS
310 only): -30° (-22°F) to +70°C (158°F)
Humidity measurement range: 0…100%
RH
Output
current
of
humidity
measurement
•
EWHS 300: 4 (0%)…20mA (100%)
•
EWHS 310: 0 (0%)…20mA (100%)
Output current of temperature
measurement
EWHS 310: 0 (-30°C)…20mA (+70°C)
Response time under constant conditions
(63%) at 23°C (73.4°F): 30 seconds
Saturation recovery time: 90 seconds
Storage temperature:
-30°C (°F) to +80°C (176°F)
Number of connection wires:
•
EWHS 300: 2
•
EWHS 310: 4
CHEMICAL RESISTANCE
The values shown in the table below are
given only for guidance purposes. The
chemical resistance of the sensor is
highly affected by the prevailing humidity
and temperature conditions and by the
length of exposure time to the pollutant.
Exposure to higher concentrations is
possible provided that exposure time is
shorter and that the sensor can then
recover in a "clean" environment or in a
flow of gas (purging).
Permissible error due to exposure to a
pollutant is ± 2 % RH
Pollutant Table
Maximum load: 250 Ohm
Humidity measurement accuracy
(at
23°C/73.4°F):
EWHS 300:
±2% RH (10..95% RH)
±3% RH (<10% >95% RH)
EWHS 310:
±1.5% RH (10..95% RH)
±2% RH (<10% >95% RH)
Temperature measurement accuracy at
0°C (32°F) and 23°C (73.4°F) (EWHS 310
only): 0.5°C (for different temperature
values, accuracy is that of Pt100B plus
0.2°C)
Air filter: polyethylene
Reverse polarity protection: by diode
Temperature compensation:
•
EWHS 300: with NTC
•
EWHS 310: with Pt100B
Max. air speed: 20m/s
DISCLAIMER
This manual and its contents remain the
sole property Invensys Controls Italy
s.r.l. and shall not be reproduced or
distributed
without
authorization.
Although great care has been exercised
in the preparation of this document,
Invensys Controls Italy s.r.l., its
employees or its vendors, cannot accept
any liability whatsoever connected with
its use. Invensys Controls Italy s.r.l.
reserves the right to make any changes
or improvements without prior notice.
The valu es sh own i n the table be lo w (Pollu ta nt Table)
Pollutant
Chemical Formula
Maximum Workplace
Concentration
ppm
Acetone
Ammonia
Petrol
Chlorine
Acetic acid
Ethyl acetate
Ethanol
Ethylene glycol
Ethylene oxide
Formaldehyde
Isopropanol
2-Butanone (MEK)
Hydrochloric acid
Sulphur dioxide
Hydrogen sulphide
Nitrogen oxides
Toluene / Xylene
CH3COCH3
NH3
Cl2
CH3COOH
CH3COOC2H5
C2H5OH
HOCH2CH2OH
C2H4O
HCHO
(CH3)2CHOH
C2H5COCH3
HCl
SO2
H2S
NOx
C6H5CH3
1000
25
300
1
10
400
1000
100
3
1
400
200
5
5
10
5
100
mg/m3
2400
18
1200
1.5
25
1400
1900
260
1.2
980
590
7
13
15
9
380
C94 Permissible Concentration for
Continuous Operation
ppm
mg/m3
3300
5500
800
4000
3500
1200
0
2400
4800
3300
300
5
350
5
1300
8000
4000
150000
2
2000
15000
6000
3000
0
3000
12000
8000
500
13
500
9
5000
EWHS 300/310
2000/12
300/310
Cod:EWHS
9IS22006
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