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Issue date: 12.05.2022
Thermokon Sensortechnik GmbH, Platanenweg 1, 35756 Mittenaar, Germany · tel: +49 2778 6960-0 fax: -400 www.thermokon.com· [email protected]
FT-RDF18+_RS485_Modbus_Datasheet_en.docx © 2022
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BUILD-UP OF SELF-HEATING BY ELECTRICAL DISSIPATIVE POWER
Sensors with electronic components always have a dissipative power, which affects the temperature measurement of the ambient air. The
dissipation in active temperature sensors shows a linear increase with rising operating voltage. This dissipative power has to be considered when
measuring temperature. In case of a fixed operating voltage (±0,2 V) this is normally done by adding or reducing a constant offset value.
Thermokon transducers can be operated with variable operating voltages. The transducers are set at the factory with a reference operating voltage
of 24 V =.
At this voltage, the expected measuring error of the output signal will be the least. Other operating voltages, can cause a measurement deviation
changing power loss of the sensor electronics.
A recalibration can be carried out directly on the unit or via a software variable (app or bus).
Remark: Occurring draught leads to a better carrying-off of dissipative power at the sensor. Thus temporally limited fluctuations might
occur upon temperature measurement.
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APPLICATION NOTICE FOR HUMIDITY SENSORS
For standard environmental conditions re-calibration is recommended once a year to maintain the specified accuracy. A re-calibration may be
required sooner than specified, or the sensor element may have to be exchanged when exposed to the following environmental conditions:
•
Mechanical stress
•
Contamination (dust / fingerprints e.g.)
•
Abrasive chemicals
•
Environmental influences (e.g. condensation on measuring element)
Re-calibration and deterioration of the humidity sensor due to environmental conditions are not subject of the general warranty.
Refrain from touching the sensitive humidity sensor/element. Touching the sensitive surface will void warranty.
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TECHNICAL DATA
Measuring values
temperature, humidity (humidity output configurable)
Output voltage
2x 0..10 V or 0..5 V, min. load 10 kΩ (live
-zero configuration via Thermokon USEapp)
Network technology
RS485 Modbus, RTU, half-duplex, baud rate 9.600, 19.200, 38.400 or 57600, parity: none (2 stopbits), even
or odd (1 stopbit)
Power supply
15..35 V = or 19..29 V ~ SELV
With alternating voltage, the correct polarity must be ensured
Power consumption
max. 0,4 W (24 V =) | 0,8 VA (24 V ~)
Measuring range temp.
-20..+80 °C (default setting), optionally configurable via Thermokon USEapp
Measuring range humidity
0..100% rH non-condensing, optionally configurable via Thermokon USEapp (enthalpy, absolute humidity,
dew point)
Accuracy temperature
±0,3 K (typ. at 21 °C)
Accuracy humidity
±2% between 10..90% rH (typ. at 21 °C)
Display
(optional)
LCD 29x35 mm with RGB backlight
Enclosure
enclosure USE-M, PC, pure white,
with removable cable entry
with LCD Display (optional)
cover PC, transparent
Protection
enclosure
IP65 according to EN 60529
sensor head
IP30 according to EN 60529
Cable entry
M25 for cable max. Ø=7 mm, seal insert for fourfold cable entry
Connection electrical
removable plug-in terminal (Mainboard: max. 2,5 mm² / Plug-in card: max 1,5 mm²);
connection wire sensor head to plug RJ12: PVC 0,15 m;
connection wire bush RJ12 to enclosure: PVC 3 m
Sensor head
ABS, white, Ø=30 mm
Ambient condition
-35..+70 °C, short term condensation
When several BUS devices are supplied by one 24 V AC voltage supply, it is to be ensured that all “positive” operating voltage input terminals (+) of the field devices
are connected and all “negative” operating voltage input terminals (-) (=reference potential) are connected (in-phase connection of field devices).In the case of reversed
polarity at one field device, a supply voltage short-circuit would be caused by that device.
The consequential short-circuit current flowing through this field my cause damage to it. Therefore, pay attention to correct wiring.
