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DESCRIPTION
HD 2007T... and HD 2008T... are microprocessor configurable humidity and
humidity-temperature 4÷20 mA transmitters. The temperature range is configurable.
They convert humidity and temperature values into two linear current signals (2 wires)
in the field 4÷20 mA. In the humidity-temperature combined version, the two circuits
and the related outputs are completely independent one from the other. The lineariza-
tion based on digital technique grants best accuracy and stability. Programming is car-
ried out very easily by pressing a button. No operation by means of jumpers, poten-
tiometers, etc. is requested. The humidity input can be recalibrated using two saturated
solutions: the first one at 75%, the second one at 33%; the 0% R.H...100% R.H. rela-
tive humidity range is fixed and 4 mA correspond to 0% R.H., while 20 mA to 100%
R.H. In HD 2008 model, the operator can configure 4÷20 mA (or 20÷4 mA) temperature
output in any range going from -50°C up to +200°C with 25°C minimum amplitude. A
LED indicates the alarm states (temperature exceeding set-point, sensor failure or
short-circuit) and helps the operator when programming.
Important remark: the relative humidity sensor may work in a -30...+140°C temperature
range. Beyond this range data are not correct and the sensor may be damaged.
INSTALLATION AND CONNECTION
TECHNICAL DATA (@ 20°C e 24 Vdc)
Model
Capacity
Accuracy at 20°C
Relative humidity operating
range
Temperature operating range
of relative humidity sensor
Wire length
Working static pressure
of sensor
When using the transmitter, check sensor compatibility with the atmosphere where it is installed
Sensor
Connection
Transducer energized
Measuring range
Accuracy 20°C
4...20 mA R.H.
4...20 mA Temperature
22 mA
Linearization
Power supply for every input
Maximum load (see fig. 3)
No filter
With filter
Working temperature electronics
Electronics protection class
(*) Time necessary to reach 63% of total variation
(**) In the event that measured temperature "T" exceeds T1...T2 (T1<T2) selected range, temperature transmitter
holds 4 mA for T<T1 and 20 mA for T>T2 for a 10°C dead band before going on error at 22 mA.
Figure 11 shows the mechanical dimensions of the transmitters and the holes to fix
the case. Figures 1 and 2 show current loop connection diagram. The RL (load) sym-
bol identifies any device part of the current loop, that is: either a panel meter, a con-
troller, a data logger or a recorder.
Measure accuracy is not affected by the position of the transmitter. However, it is
suggested to install the transmitter with the sensor oriented downwards to minimize
dust settling on sensor protection filter. The transmitter shall not be mounted neither
near a heating source - as heating air causes a decrease in relative humidity (by the
same quantity of water vapour) - nor near doors, in presence of rushes of air; but
movements of air mustn't miss.
When using the transmitter, check sensor compatibility with the atmosphere
where it is installed.
MOUNTING
The instrument is offered in three different configurations to meet any applicative need.
They are:
TO horizontal version, suitable for duct installations; an adjustable connection fitting is
available for wall or duct mounting (1/2" gas thread).
TV vertical version suitable for wall-mounting
TC version with wire. The sensor is connected to the electronics by means of a differ-
ently long wire. It can work in a temperature range from -30°C up to +140°C.
Attention: in TC models the sensor and the electronics have the same serial
number. They can be exchanged with other transmitters only if the instrument is
recalibrated with the new sensor.
PROGRAMMING
The transmitters of HD 2007T... and HD 2008T... series are supplied with relative
humidity and temperature sensors calibrated with current outputs and a 4...20 mA
range. 4 mA corresponds to 0% R.H. and to 0°C; 20 mA corresponds to 100% R.H.
and to 100°C. The user can re-calibrate the humidity sensor (holding the 4 mA = 0%
and 20 mA = 100% R.H. correspondence) and set a different temperature output
range.
A) Humidity Sensor Calibration
HD 2007
HD 2008
P-14
100...200pF
±2% (5±90%)
±2.5% (in the remaining range)
5...98% R.H.
-40...+150°C
TC version = 1.5 m, 5 m e 10 m
20 bar
Pt100, 100 Ω at 0°C (α=0.00385)
----
----
3 (or 2) wires
----
<1 mA
----
-50...+200°C
----
±0.1°C ±0.1% of reading
0...100% R.H.
0...100% R.H.
----
Configurable in the range -50...200°C
(min. amplitude: 25°C)
In case of faulty programming, of disconnected probe
or of temperature exceeding selected range.
The alarm red LED is lighted. (**)
Digital
7...30 Vdc
= 770 Ω a 24 Vdc
R
R
=
Lmax
Lmax
6 seconds
2 minutes
-10...+70°C
IP 67
The following accessories are requested: a 7÷30 Vdc continuous power supply, a best
accuracy ammeter with 0...25 mA min. range.
The calibration of the humidity sensor is executed on two fixed points, 75.4% R.H. -
always the first point - and 33% R.H. - the second point - , according to the following
instructions:
• power the instrument as shown in the connection diagrams of Figure 1 (HD 2007T...)
and Figure 2 (HD 2008T...);
• put the sensor inside the case containing the 75% R.H. saturated solution and wait for
30 minutes, at least;
• move the jumper from "MEASURE" to "CAL 75%" position;
• press the small key "Program Switch R.H." and hold it for 5 seconds until the corre-
sponding LED does not flash. It is now possible to release the key: the LED remains
lighted; a sensor put inside the probe compensates the temperature difference of the
solution as to 20°C.
• put the sensor in the case containing the 33% R.H. saturated solution and wait for 30
minutes;
• move the jumper to "CAL 33%" position;
• press the small key "Program Switch R.H." and hold it for 5 seconds until the corre-
sponding LED is off. It is now possible to release the key; the ammeter displays a cur-
rent of 9.28 mA if the solution is at 20°C. But if the temperature of the solution is differ-
ent, the current displayed by the ammeter has the same value as indicated in the fol-
lowing schedule:
• move again the jumper on "MEASURE". The calibration of the R.H. probe is over.
°C
10
% U.R.
33.4
mA
9.34
Important remark: the first calibration point has to be always at 75% R.H.
B) 4÷20 mA temperature output programming HD 2008T... models only
The following accessories are requested:
• 7÷30 Vdc continuous power supply,
• Calibration of Pt100 or of a set of best accuracy resistances,
• Best accuracy ammeter with 0...25 mA min. range.
Procedure:
• Connect HD 2008T... temperature section as shown in fig. 2, set Pt100 calibrator at a
temperature corresponding to 4 mA. For example: let's suppose to adjust a
-10...+120°C range and, consequently, to set the calibrator at -10°C; the equivalent
resistance value will be 96.09 Ω; if the calibration is carried out with a fixed resistance,
between terminals 10 and 11, being terminals 9 and 10 short-circuited, a 96.09 Ω
fixed resistance will be connected.
• Wait 10 seconds in order to get a steady measurement, press "Program Switch °C"
programming key for 5 seconds, until the led flashes once and then remains lighted;
• Set Pt100 calibrator at the value established for 20 mA. According to the above men-
tioned example, the calibrator setting shall be +120°C; the equivalent resistance value
will be 146.07 Ω; if the calibration is carried out with a fixed resistance, between termi-
nals 10 and 11, being terminals 9 and 10 short-circuited, a 146.07 Ω fixed resistance
will be connected.
(Vcc-7)
• Wait 10 seconds in order to get a stable measurement, press for 5 seconds the
22 mA
"Program Switch °C" key until the LED is off. When releasing the key, the LED will
flash twice to confirm programming has been executed. The SET POINT procedure is
over.
• Check that the configuration meets requested specifications by setting the calibrator
at the values corresponding to 4 and 20 mA (or connecting the precision resistances)
and checking current in the ammeter.
ORDER CODES
HD 2007TO/1: relative humidity 2-wire passive transmitter, 4÷20 mA output. Duct horizontal fixed
sensor L=130 mm.
HD 2007TV: relative humidity 2-wire passive transmitter, 4÷20 mA output. Wall-mounting vertical
fixed sensor.
HD 2007TC/1: relative humidity 2-wire passive transmitter, 4÷20 mA output. Sensor L=130 mm con-
nected directly to the instrument by means of a 1.5 m long wire.
HD 2007TC/2-5: relative humidity 2-wire passive transmitter, 4÷20 mA output. Sensor L=330 mm
connected directly to the instrument by means of a 5 m long wire.
HD 2007TC/2-10: relative humidity 2-wire passive transmitter, 4÷20 mA output. Sensor L=330 mm
connected directly to the instrument by means of a 10 m long wire.
HD 2008TO/1: relative humidity and temperature duct configurable 2-wire passive combined trans-
mitter, 4÷20 mA double output. Duct fixed horizontal sensor L=130 mm.
HD 2008TV: relative humidity and temperature duct configurable 2-wire passive combined transmit-
ter, 4÷20 mA double output. Wall-mounting fixed vertical sensor.
HD 2008TC/1: relative humidity and temperature duct configurable 2-wire passive combined trans-
mitter, 4÷20 mA double output. Sensor L=130 mm connected directly to the instrument by means of
a 1.5 m long wire.
HD 2008TC/2-5: relative humidity and temperature duct configurable 2-wire passive combined
transmitter, 4÷20 mA double output. Sensor L=330 mm connected directly to the instrument by
means of a 5 m long wire.
HD 2008TC/2-10: relative humidity and temperature duct configurable 2-wire passive combined
transmitter, 4÷20 mA double output. Sensor L=330 mm connected directly to the instrument by
means of a 10 m long wire.
15
20
25
30
35
33.3
33
32.7
32.4
32
9.33
9.28
9.23
9.18
9.12
40
45
50
31.6
31.1
30.5
9.06
8.98
8.88
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