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HYGROMER®- MP 400 A
Meteorology probe
Operating Instructions
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1. Introduction
With the HYGROMER® meteorology probe MP 400A for measuring humidity and temperature, you have
purchased a precision measuring instrument which incorporates more than 25 years experience of the
company ROTRONIC AG in this special field.
Special resistance to air pollutants is achieved by the HYGROMER
®
sensor IN-1 which, in combination
with the sophisticated electronics, guarantees outstanding measuring accuracy. When the following
instructions are observed, many years of perfect operation and long-term stability of the probe and thus
reliable measurement are assured.
The HYGROMER
®
meteorology probe is a combined humidity and temperature probe for use in
meteorology and similar demanding applications, for example in tunnels, on motorways, airports etc.
Except for the sensor element, the HYGROMER
®
meteorology probe is protected against unintentional
penetration of humidity. Its linear voltage output has been matched to the requirements of data collection
and transmission systems.
We accept no liability for damage and disturbances which result from non-observation of these operating
instructions.
You can obtain further copies of these operating instructions either from ROTRONIC AG or one of our
representatives.
2. Start-up
The HYGROMER® meteorology probes can be connected to external power supplies and signal
processing circuits with the 4-pin Tuchel connector installed as standard.
(Connection diagram see chapter 8).
The probe must be protected against water splashes and rain. A weather and radiation protector is
available from ROTRONIC AG as an accessory. Additional sensor protection is necessary for air
velocities greater than approx. 20 m/s, otherwise the sensors can be damaged.
Important!
Incorrect voltage supplies and overloading of the outputs can destroy the probe!
3. Performance of measurements
The HYGROMER® meteorology probes (relative humidity and temperature) are factory adjusted before
delivery, for which reason checking upon reception of the instrument is not necessary as a rule.
The probe is ready for use half a second after being switched on.
Important!
Before a reliable measurement can be made, the measuring probe and medium to be measured must be
in temperature and humidity equilibrium.
Example: At 50 %RH and 23 °C, a temperature difference of 1 K (between sensor and the medium to be
measured) causes a humidity error of about 3 %RH!
The necessary adjustment time, which can last up to 30 minutes, depends upon several factors:
- Size of the humidity and temperature deviation of probe and medium before start of measurement
- Change of the measured values during the adjustment time.
The humidity measurement delivers a better picture of the progress of acclimatization since it reacts
much more quickly and more sensitively than the temperature measurement. The 1/10 percent display is
therefore very suitable as a trend display. If the display oscillates about a mean value, then adjustment is
completed.
Due to the HYGROMER
®
IN-1 sensor, specially developed for the HYGROMER® meteorology probe,
insensitivity to chemical influences far beyond the MAK value range is largely guaranteed (MAK =
Maximum workplace exposure)
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4. Sources of errors
Humidity measurements are very sensitive to various influences:
- Temperature errors
Due to too short adjustment time, sunshine during the measurement, heating, cold outer wall, air
draft (e.g. fans), radiating hand and/or body heat etc.
- Humidity errors due to steam, water splashes, dripping water or condensation on the sensor etc.
Repeatability and long-term stability in operation are not impaired by this even if the probe has
been exposed to high humidity or saturation with water vapour over a lengthy period.
- Contamination
of the humidity sensor can be largely avoided by using a corresponding filter. The filters must be
cleaned or replaced periodically depending upon the degree of contamination of the measuring
site.
Important!
The sensor is insensitive to chemicals, when they occur in normal concentrations (MAK values). At higher
concentrations or possibilities of contact with liquid chemicals, the manufacturer must always be
consulted!
5. Warranty
For verifiable material and manufacturing errors, the factory warranty is 12 months from the date of
delivery. Please refer to the "General conditions of sales and delivery" for details.
We accept no liability if this instrument is used in applications for which it is not intended.
6. Maintenance and service
6.1 Temperature
The probes are adjusted before delivery. A temperature readjustment is normally not required. When in
doubt about the correct calibration, please ask ROTRONIC AG.
6.2 Humidity
The probes are adjusted before delivery at 35 %, 80 % and 10 %RH. This results in optimum accuracy
over the full measuring range. To maintain this accuracy, we recommend you to subject the probe to a
check at least once a year. Please use only the ROTRONIC AG humidity standards for this!
These humidity standards consist of unsaturated salt solutions which can be kept indefinitely.
Important!
The ROTRONIC AG humidity standards (CH poisonous category 3) are normally not dangerous to
humans, but can irritate sensitive skin. In the case of contact with the skin or the eyes, the solution must
be washed out immediately and thoroughly with plenty of water. The ROTRONIC AG humidity standards
must not be consumed!
The calibration device for calibration and adjustment suitable for your type of probe and the required
humidity standards are obtainable as an accessory from ROTRONIC AG or one of our representatives.
Definitions:
Calibration = Control measurement with a ROTRONIC AG humidity standard
Adjustment = Calibration + additional readjustment of the probe to the set point value.
It is necessary to observe the following rules during calibration:
a) Calibrate in a room with constant temperature (if possible 23 °C ±2 °C) and avoid any thermal
influence which could influence the measurement: (air) draft, sunshine, heating, fans etc.!
b) Place the probe and especially its calibration device on an insulating surface (e.g. the lid of the
calibration set) so that there can be optimum temperature adjustment.
c) Start with the calibration point of 35 %RH (potentiometer H35) and then adjust the points of 80 %RH
(potentiometer H80) and 10% RH (potentiometer Hmin) with a second and third calibration.
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Calibration steps:
1. Unscrew the lower part (cup) of the calibration device.
2. Unscrew the probe's sensor protector and screw the calibration device
onto the probe. Proceed carefully so as not to damage the sensors!
3. Remove the 3 small screws on the probe housing and take out the
print.
4. Insert a textile pad in the cup.
5. Shake the ampoule until the entire fluid is in the thick part of the
ampoule.
6. Break off the neck of the ampoule at the fracture point (white line) and
empty the entire contents into the centre of the textile pad (you may
have to knock it a little).
7. Screw the cup immediately into the calibration device from below.
8. Place the calibration device on the insulating surface and leave it for
at least 1 hour.
9. Check the display; if necessary readjust on the associated
potentiometer with a small screwdriver (see diagram).
10. Remove cup from the calibration device.
11. Remove the textile pad and dispose of with the household rubbish.
(The textile pads are designed for single use only and must not be
reused under any circumstances.)
12. Wash the cup out thoroughly under running water and dry it carefully.
13. According to which calibration method you have chosen, repeat the
process from item 4 to 12 with the corresponding humidity standards.
14. Push the print back into the housing and screw tight.
15. Remove the calibration device carefully and reattach the sensor protector.
Component side Soldering side
6.3 Contamination
Contaminated filters can cause measuring errors and prolong the adjustment time. Depending upon the
degree of contamination of the filter, it must be cleaned or if necessary replaced periodically.
In order not to damage the sensors, unscrew the filter for cleaning. Clean the filter with soapy water,
alcohol or a cleaning agent suitable for removing contamination and rinse thoroughly with water. Do not
screw the filter back onto the probe until it is completely dry. Replace filters which can no longer be
cleaned with new ones. Should the sensors be severely contaminated despite of the protective filter, we
recommend having these replaced by our service department.
7. Accessories and spare parts
Please be sure to use only ROTRONIC original accessories and spare parts from our current sales
catalogue "HUMIDITY AND TEMPERATURE MEASUREMENT".
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8. Technical data MP 400A series
Humidity sensor ROTRONIC-HYGROMER® IN-1
Temperature sensor RTD Pt 100 1/3 DIN
Operating ranges: Humidity 0...100 %RH Temperature -40...+60 °C
Accuracy at 23 °C:
Humidity:
Temperature:
±1 %RH (5...95 %RH) ± 2% RH < 5 %, > 95 % RH)
±0.3 °C
Reproducibility:
Humidity
Temperature
< 0.5% RH
< 0.1 °C
Long term stability for humidity
typical under normal conditions
< 1 % RH/year
Time constants at 23 °C and 1 m/s air movement: Humidity < 10 s Temperature < 15 s
Adjustment points (potentiometers)
Humidity
100% limit
Temperature
35%,80%, 10%
Hmax
Tmin, Tmax
Output signals humidity :
-MP404A, MP405A, MP406A
-MP407A, MP408A, MP409A
0...20 mA = 0...100 %RH
4...20 mA = 0...100 %RH
Output signals temperature:
MP404A
MP405A
MP406A
MP407A
MP408A
MP409A
0...20 mA = 0...100 °C
0...20 mA = -40...60 °C
0...20 mA = -30...70 °C
4...20 mA = 0...100 °C
4...20 mA = -40...60 °C
4...20 mA = -30...70 °C
Load per output
<500 :
Supply voltage: MP402A & MP403A
Other types
Example: Load 100 ::
8 +(0.02*load) VDC; max 26.5 VDC
Min. 5 +(0.02*load) VDC; max. 26.5 VDC
5+(0.02*100) VCC = 7 VDC
Max. current consumption 50 mA
Probe connection (Standard) 7-pin Tuchel plug
Sensor protection: Wire mesh filter
Weight 70 g
8.1 Connector wiring
Connection designations
+ Supply voltage + VDC
GND Common ground (-),- VDC
RH Humidity (+)
T Temperature (+)
0 Cable compensation
View of the connection side of the opposite connector
Version with 4-pin Tuchel connector
Example: MP404A-T4-W4W
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8.2 Connection cables without connectors
Code CP PVC cable
Code CG PUR cable grey
Example: MP404A-CG-02...
Colour of wire
Supply voltage + VDC green
Relative humidity % RH (+) white
Temperature T (+) brown
Compensation 0 yellow
Common ground (-), -VDC /GND shield
8.3 Explanation of the article numbers (order no)
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