Delta OHM HD 9007 Serie Manual Del Usuario página 4

HD9008TR - HD9009TR
RH AND TEMPERATURE TRANSMITTERS
CHARACTERISTICS
The HD9008TR and HD9009TR are single block RH and temperature
microprocessor transmitters, temperature configurable. The HD9008TR is a
passive transmitter with a 4...20mA output and 7...30Vdc power supply; the
HD9009TR is a transmitter with a 0...1V standard voltage output (other outputs
available on demand) and 7...30Vdc power supply. Sensors are mounted at the
end of a plastic tube: a capacitive humidity sensor and a Platinum temperature
sensor (100Ω @0°C).
The instrument can be reprogrammed by means of a key, and no jumper or
potentiometer actions are required. The humidity input can be recalibrated by
using two saturated solutions: the first one at 75%, the second one at 33%; the
0%RH...100%RH relative humidity range is fixed, 4mA (or 0Vdc) correspond to
0%RH, 20mA (or 1Vdc) equal 100%RH.
Temperature standard configuration is –40...+80°C for the HD9008TR and
–40...+60°C for the HD9009TR, corresponding to 4...20mA and 0...1Vdc,
respectively.
The user can configure the temperature output in ranges different from the
standard one by means of a Pt100 simulator or of a set of fixed resistances,
provided that it is included in the -40°C...+80°C range with a minimum amplitude
of 25°C. Two LEDs give alarm indications (temperature exceeding set range,
sensor breakage or short-circuit) and help the operator when programming.
An out-of-standard temperature operating range can be requested when placing
the order.
Important Warning: probes work in the -40°C...+80°C temperature range. Outside
this range data are not correct; electronics is designed to operate in this range.
SENSORS
The humidity sensor is a condenser which dielectric is made up by an
hygroscopic polymer. As water dielectric constant is approximately 80, you'll get
a strong change in capacity as the humidity content of this polymer changes. The
advantages of this kind of sensor are: good linearity, insensitivity to temperature
changes, fast response time and long-lasting life. The sensor temporary looses
its accuracy if some condensation develops on its surface (the transmitted value
is higher than the real one because of an increase in effective capacity).
The temperature sensor is a Platinum resistance thermometer (100Ω @0°C).
The Pt100 resistance variation is transformed into a current or voltage signal,
linear to temperature.
SIGNAL TRANSMISSION
The electronic circuit design provides the signal to increase linearly as humidity
and temperature raise.
In presence of cables transmitting high currents or machines causing
electromagnetic noises, the transmitter connection cables have to be placed in a
separate raceway, or far from them, to prevent these noises. It is recommended
to use a shielded cable for the connections of instruments having a voltage output
(HD9009TR).
INSTALLATION AND ASSEMBLY
Figures 1 and 2 show the connection diagram of the two models. RRH and R°C
represent the current input of any device connected to the 4...20mA loop, that is:
an indicator, a controller, a data logger or a recorder. In figure 2, "Vin%RH and
Vin°C" symbols have the same meaning.
Accuracy in measuring does not depend on the transmitter position. However, it
is suggested to install the transmitter with the sensor faced downwards (where
possible) to reduce dust deposit on the sensor protection filter. The transmitter
shall not be mounted next to doors, in draughtiness, in areas with scarce air
circulation, or near a heat source, as heating air involves a decrease of relative
humidity (the quantity of available water vapour being equal).
Protection degree: IP54.
Ensure that the sensor is compatible with the atmosphere where it is
installed.
Follow these procedures to access the transmitter terminal board (see fig.3):
Unscrew grommet "A", take off rubber bulb "B" and unscrew bottom "C". Insert the
cable through A, B and C elements and connect it to the terminal board. Hold the
cable firmly while screwing grommet "A" to avoid twisting.
PROGRAMMING
HD9008TR and HD9009TR relative RH and temperature transmitters are factory
calibrated. The HD9008TR is provided with a 4...20mA current output, while the
HD9009TR with a 0...Vdc voltage output.
In the HD9008TR standard configuration, 4mA correspond to 0%RH and –40°C,
while 20mA equal 100%RH and +80°C.
In the HD9009TR one, 0Vdc corresponds to 0%RH and –40°C, while 1Vdc
equals 100%RH and +60°C.
The user can re-calibrate the RH probe holding the 0%...100%RH range and
setting a different range for temperature, as long as it is within –40 and +80°C
limits.
Figure 4 shows the transmitter programming elements.
Humidity Sensor Calibration
The following accessories are needed.
HD9008TR model: a 7...30Vdc continuous voltage power supply, a precision
ammeter with a 0...25mA min. range.
HD9009TR: a 7...30Vdc continuous voltage power supply, a precision voltmeter
with a 0...1Vdc min. range.
The calibration of the humidity sensor is carried out at two fixed points: at
75.4%RH – always as first point – and at 33%RH – second point.
Procedure:
1. To access the panel board, unscrew grommet "A" (see fig. 3) and hold the
cable firmly to avoid twisting. Take off the rubber bulb and unscrew the bottom
of the instrument.
2. Connect the wires to provide the instrument with power supply, as shown in
the connection diagrams (Fig. 5: HD9008TR and Fig.6: HD9009TR).
3. Insert the probe in the container with the saturate solution at 75%RH and
wait 30 minutes at least. Probes and solutions have to be at the same
temperature.
4. Turn 75%RH dip-switch on ON.
5. Press the CAL%RH little key and hold it down for 5 seconds, at least, until
the corresponding LED does not flash. Now the little key can be released:
the LED will remain on. A built-in sensor compensates the temperature
difference of the solution compared with 20°C.
6. Turn the 75%RH dip-switch on OFF.
7. Put the probe in the container with the saturate solution at 33%RH and
wait for 30 minutes, at least. Probes and solutions have to be at the same
temperature.
8. Turn the 33%RH dip-switch on ON.
9. Press the CAL%RH small key and hold it down for 5 seconds, at least, until
the corresponding LED is not off. Now the little key can be released.
If the solution is at 20°C, the output will equal 9.28mA (in HD9008TR model)
and 0.330V (in HD9009TR model). If the solution is at a different temperature,
the output will correspond to the value listed in the following table:
°C 10 15 20
%RH 33.4 33.3 33
mA
9.34 9.33 9.28
V 0.334 0.333 0.330 0.327 0.324 0.320 0.316 0.311 0.305
10. Turn the 33%RH dip-switch on OFF again.
11. Re-close the instrument: re-screw the bottom, put the rubber bulb again at its
place and screw the grommet: hold the cable firmly to avoid twisting it.
12. The calibration of the RH probe is finished.
Important Note: the first calibration point has to be always at 75%RH
Programming of Temperature Operating Range
The following accessories are needed.
For HD9008TR: a 7...30Vdc continuous voltage power supply, a precision
ammeter with 0...25mA minimum range.
For HD9009TR: a 7...30Vdc continuous voltage power supply, a precision
voltmeter with 0...1Vdc minimum range.
Pt100 simulator or a set of precision resistances.
Procedure:
1. To access the panel board, unscrew grommet "A" (see figure 3) and hold the
cable firmly to avoid twisting. Take the rubber bulb off and unscrew the bottom
of the instrument.
2. Unscrew the sensor protection filter.
3. Unsolder the Pt100 sensor (the narrowest one) and in place of it, solder the
output wires or those of a Pt100 simulator or of a precision resistance, as
shown in figures 7 and 8. Then wait a few seconds for the junction to get
cold.
4
25 30 35 40 45
32.7 32.4 32 31.6 31.1
9.23 9.18 9.12 9.06 8.98
50
30.5
8.88