DO 9861T humidity and temperature transmitters convert the humi-
dity and temperature measured by two sensors into a 4÷20 mA
signal.
An LCD indicator allows the value of the process signal and the various para-
meters to be displayed.
The accurate design and choice of components make the instruments preci-
se and reliable for a long working life. The R.H. sensor is temperature com-
pensated.
The instruments have two sensors, a capacitive sensor for measuring relative
humidity and a Platinum resistive sensor (Pt100, 100 Ω at 100°C) for measu-
ring temperature.
The transmitters measure the relative humidity (% RH), the sensor tempera-
ture (TC), and calculate the wet bulb temperature (WT), the dew point tempe-
rature (DP), the absolute humidity (gr/m
of water per kg of dry air). The temperatures are expressed in degrees
Celsius.
The measurements refer to an atmospheric pressure of 1013.25 mbar.
Once the physical quantity to be checked has been selected, the output current
will be proportional and the status of the relays will depend on that variable.
Technical characteristics DO 9861T
Capacity
390...570 pF
Transducer energizing
10 kHz
Cable length
<10 m multiple screen (about 2 nF)
additional error about 0.003 pF/pF
Accuracy
Instrument: 0.1% of reading ±1 digit ±0.01%/°C
Sensor: ±2.5% (5...90%), +3/-2.5% (90...98%)
Working range of sensor
Relative humidity: 5...98% @ 23°C
Dew point temperature (DP°C):
-60..+100 DP°C (-20 DP°C @ 23°C)
Temperature range: -40..+150°C
During use, check that the sensor is compatible with the atmosphere used
2/4 wires Pt100
-50...+199.9°C
Transducer energizing
0.5 mA DC
Cable length
<10 m not screened
<50 m screened (about 5 nF)
Accuracy
0.2°C ±0.1% of reading ±0.01°C/°C
4.00...20.00 mA
Dry bulb temperature -50.0...+199.9°C
Wet bulb temperature -50.0...+199.9°C
Relative humidity 0.0...+100.0% RH
Absolute humidity 0.0...+1999 gr/m
Mixing ratio 0.0...+1999 gr/Kg of air
Accuracy
±2.5% RH
0.5% of reading ±0.02 mA
Load resistance
R
Lmax
A and B
Bistable exchange contacts 3 A/230 V ac potential
free contact
Passive
4÷20 mA, 10...35 V dc, see figure 2
Active
24 or 230 V ac -15/+10%, 1 VA, 48...62 Hz, see figure 1
Front panel
122x120 mm
External dimensions
122x120x56 mm
Protection class
IP64
Safety
EN61010-1 level 3
Electrostatic discharges
EN61000-4-2 level 3
Fast electric transient
EN61000-4-4 level 3
High energy transient
EN61000-4-5 level 3
Voltage variation
EN61000-4-11
Sucseptibility to
IEC1000-4-3 10 V/m
electromagnetic interference
Emission of
EN55020 class B
electromagnetic interference
Key functions
PRG
Programming of the parameters is activated by pressing the PRG
s
key along with the
and
display to indicate that parameter P1 is being programmed. When
the PRG key is pressed in sequence the messages P2, P3, etc.
appear as well as the corresponding parameters. After P13 the
instrument returns to normal function.
SET
Key for setting the relay intervention threshold. The ON or OFF sym-
bol appears on the display to indicate that the instrument is showing
the switching on or the switching off threshold of relay A or relay B.
) and the mixing ratio (gr/kg - grams
3
3
Vdc-10
Ω
=
R
= 636
@ Vdc = 24 Vdc
Lmax
0,022
t
keys. The message P1 appears on the
TD/TW When this key is pressed the dry bulb temperature TD or the wet
bulb temperature TW is shown at the top of the display.
UNIT
- When this key is pressed the dew point temperature (DP), the rela-
tive humidity (% RH), the absolute humidity (gr/m
per cubic metre of dry air) or the mixing ratio (gr/kg, grams of water
per kg of dry air) is shown at the bottom of the display.
- When pressed along with the CAL key it activates the humidity
sensor calibration function.
OK
Confirms the programming parameters, or the relay SET values, and
stores them.
CAL
- When pressed along with the UNIT key it activates the humidity
sensor calibration function.
- Key used to confirm the calibration of the humidity sensor.
s
- Key used to increase the value displayed during programming of
the parameters.
- During programming of the relay SET points.
- During calibration.
t
- Key used to decrease the value displayed during programming of
the parameters.
- During programming of the relay SET points.
- During calibration.
Display
Symbol description
TD
indicates that the value shown is the dry bulb temperature in °C.
TW
indicates that the value shown is the wet bulb temperature in °C.
DP
indicates that the value shown is the dew point temperature in °C.
% RH
indicates that the value shown is the relative humidity.
gr/m
3
indicates that the value shown is the absolute humidity (gr per m
gr/kg
indicates that the value shown is the mixing ratio (gr per kg of dry air).
A
indicates that relay A is ON.
B
indicates that relay B is ON.
ON
indicates that the value shown corresponds to the closing thre-
shold of the contacts of relay A or B.
OFF
indicates that the value shown corresponds to the closing thre-
shold of the contacts of relay A or B.
Programming the parameters
It is possible to select the corresponding quantities:
- Dry bulb temperature (TD °C)
- Wet bulb temperature (TW °C)
- Dew point temperature (DP °C)
- Relative humidity (% RH)
- Absolute humidity (a gr/m
3
)
- Mixing ratio (x gr/kg).
The range that may be set for each quantity is:
- Dry bulb, wet bulb and dew point temperature: -60.0...+100.0°C
- Relative humidity: 0.0...100.0% RH
- Absolute humidity: 0.0...1999 gr/m
- Mixing ratio: 0.0...1999 gr/kg.
Parameters for the DO 9861T
P1
Physical quantity on which depends the operation of the analog output 1
(TD, TW, DP, % RH, gr/m
P2
Physical quantity on which depends the operation of the analog output 2
(TD, TW, DP, % RH, gr/m
P3
Value corresponding to 4 mA at analog output 1.
P4
Value corresponding to 20 mA at analog output 1.
P5
Value corresponding to 4 mA at analog output 2.
P6
Value corresponding to 20 mA at analog output 2.
P7
Physical quantity on which depends the operation of relay A (TD, TW,
DP, % RH, gr/m
3
, gr/kg).
P8
Physical quantity on which depends the operation of relay B (TD, TW,
DP, % RH, gr/m
3
, gr/kg).
P9
Delay time in intervention of relay A. May be set between 0 and 255
seconds both during the opening and the closing.
P10 Delay time in intervention of relay B. May be set between 0 and 255
seconds both during the opening and the closing.
P11 Calibration of Pt100 probe.
P12 Current calibration of output 1 at 4 mA and 20 mA.
P13 Current calibration of output 2 at 4 mA and 20 mA.
P14 R.H. calibration after the replacement of R.H. sensor.
To alter one of the parameters, press the PRG key until the message corre-
sponding to the parameter that is to be changed appears on the display.
5
3
- grams of water
3
3
, gr/kg).
3
, gr/kg).
3
of air).