Duct humidity- and temperature sensors KFTF-Modbus-RJ12
temperature Luftfeuchtigkeit
temperature Temperature

Duct humidity- and temperature sensors HYGRASGARD® KFTF-Modbus-RJ12

Item no. 2003-4281-6100-001
Product group: WG01

In Stock

Usually ships in 1 to 3 days
300,73 €
357,87 € incl. VAT + shipping


Duct humidity- and temperature sensors HYGRASGARD® KFTF - Modbus RJ12
Calibratable HYGRASGARD® KFTF - Modbus - T3 (±2.0%) or KFTF - 20 - Modbus - T3 (±1.8%) duct humidity and temperature transmitters with Modbus connection, in an impact resistant plastic housing with quick-locking screws, optionally with/without display and including a mounting flange. They have a plastic sinter filter (exchangeable) and serve to detect various parametres in humidity measurement. measurands include relative humidity (0...100% r.H.) and ambient air temperature (– 35...+80 °C).

These measurands are used for internal calculation of the following parametres, which can be retrieved via Modbus: relative humidity [% r.H.], absolute humidity [g/m³], mixture ratio [g/kg], dew point temperature [°C], enthalpy [kJ/kg] (ignoring atmospheric air pressure), and ambient temperature [°C]. A long-term stable, digital sensor guarantees precise measuring results.

The duct sensor is applied in non-aggressive, dust-free environments and is suitable for installation in ceilings, ducts and devices. It is used in refrigeration, air conditioning and cleanroom engineering, engineering rooms, hotels and conference facilities.
Innovative Modbus sensor with galvanically separated RS485 interface, selectable bus termination resistance, DIP switches for setting the bus parametres and bus address in current-free state, LEDs for telegram status display, two separate push-in terminals and a large back-lit three-line display with customised programming in the 7-segment and dot-matrix ranges. The sensor is factory-calibrated and can be fine-tuned to ambient conditions by an expert.

Technical details

Voltage supply
24 V AC (± 20 %) and
15…36 V DC
Power consumption
< 1.2 W/ 24 V DC; < 1.8 VA/ 24 V AC
Data points
Temperature [°C], relative humidity [% RH],
dew point [°C], absolute humidity [g / m3],
mixture ratio [g / kg], enthalpy [kJ / kg]
Measuring range, humidity
0...100 % RH
Measuring range, temperature
–35...+80 °C
Temperature deviation
typically ± 0.2 K at +25 °C
digital humidity sensor
with integrated temperature sensor,
low hysteresis, high long-term stability
Sensor protection
plastic sinter filter, Ø 16 mm, L = 35 mm, exchangeable
(optional metal sinter filter, Ø 16 mm, L = 32 mm)
Measuring ranges
0...100 % RH
–35...+80 °C
Zero point offset
± 10 % RH (humidity)
± 5 °C (temperature)
Ambient temperature
–30...+70 °C
clean air and
non-aggressive, non-combustible gases
Bus protocol
Modbus (RTU mode),
address range 0...247 selectable
Signal filtering
4 s / 32 s
Process connection
by mounting flange, plastic
(included in the scope of delivery)
RJ12 plug
Protective tube
PLEUROFORM, material polyamide (PA6), with torsion protection,
Ø 20 mm, NL = 235 mm (optionally 100 mm), vmax = 30 m/s (air)
(option on request in stainless steel V2A (1.4301), Ø 16mm)
Electrical connection
0.2 - 1.5 mm², via push-in terminal
Cable connection
cable gland, plastic
(M 20 x 1.5; with strain relief, exchangeable,
inner diameter 8 - 13 mm) or
M12 connector according to DIN EN 61076-2-101
(optional on request)
Cable gland
2x M 20 x 1.5; with strain relief, replaceable,
inner diameter 8 - 13mm
Long-term stability
± 1 % per year
Permissible air humidity
< 95 % RH, non-precipitating air
Protection class
III (according to EN 60 730)
Protection type
IP 65 (according to EN 60 529)*
Protection type housing
IP 65
CE conformity,
electromagnetic compatibility according to EN 61326,
according to EMC Directive 2014/ 30/ EU