5
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
3
) and the mixing ratio (gr/kg - grams
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
Key functions
PRG
Programming of the parameters is activated by pressing the PRG
key along with the
s
and
t
keys. The message P1 appears on the
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.
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
3
- grams of water
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
3
of air).
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
3
- 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
3
, gr/kg).
P2
Physical quantity on which depends the operation of the analog output 2
(TD, TW, DP, % RH, gr/m
3
, gr/kg).
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.
Capacity
Transducer energizing
Cable length
Accuracy
Working range of sensor
2/4 wires Pt100
Transducer energizing
Cable length
Accuracy
4.00...20.00 mA
Accuracy
Load resistance
A and B
Passive
Active
Front panel
External dimensions
Protection class
Safety
Electrostatic discharges
Fast electric transient
High energy transient
Voltage variation
Sucseptibility to
electromagnetic interference
Emission of
electromagnetic interference
390...570 pF
10 kHz
<10 m multiple screen (about 2 nF)
additional error about 0.003 pF/pF
Instrument: 0.1% of reading ±1 digit ±0.01%/°C
Sensor: ±2.5% (5...90%), +3/-2.5% (90...98%)
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
-50...+199.9°C
0.5 mA DC
<10 m not screened
<50 m screened (about 5 nF)
0.2°C ±0.1% of reading ±0.01°C/°C
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
3
Mixing ratio 0.0...+1999 gr/Kg of air
±2.5% RH
0.5% of reading ±0.02 mA
R
Lmax
=
Vdc-10
R
Lmax
= 636
Ω
@ Vdc = 24 Vdc
0,022
Bistable exchange contacts 3 A/230 V ac potential
free contact
4÷20 mA, 10...35 V dc, see figure 2
24 or 230 V ac -15/+10%, 1 VA, 48...62 Hz, see figure 1
122x120 mm
122x120x56 mm
IP64
EN61010-1 level 3
EN61000-4-2 level 3
EN61000-4-4 level 3
EN61000-4-5 level 3
EN61000-4-11
IEC1000-4-3 10 V/m
EN55020 class B
Relative humidity
input
Temperature input
Relay
utputs
Feed
Case
CE
Conformity
During use, check that the sensor is compatible with the atmosphere used
Output current A and B
R
Load
