ROTRONIC HF3 - Manual (Page 6)

E-M-HF3-V1_22
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
HygroFlex HF3 Transmitters and Thermo-
hygrostats: User Guide Instruction Manual
Document Type
Page 6 of 27
Document title
© 2009-2011; Rotronic AG E-M-HF3-V1_22
3.3 Calculated parameters
Using the ROTRONIC HW4 software, the HF3 can be configured by the user to calculate either the dew point
or the frost point.
3.4 Analog output signals (HF32 and HF33)
HF32 and HF33: with the ROTRONIC HW4 software any of the two analog output signals can be made to
correspond to one of the following:
Relative humidity
Temperature
Dew or frost point
Any output can also be disabled.
The scale of each analog output can be set within the numerical limits of -999.99 and 9999.99.
The D/A converters used to generate the analog output signals feature a 16-bit resolution and exhibit a small
positive offset at the bottom of the signal range as indicated below:.
Signal type
Maximum offset at range bottom
0…1 V 3 mV
0…5 V 50 mV
0…10 V 90 mV
0…20 mA 4 µA
4…20 mA No offset
HF33: the ROTRONIC HW4 software allows changing the type of output signal to one
of the following: 0…20
mA, 4…20 mA, 0…1V, 0…5V or 0…10V. Both output signals are automatically configured with the same
signal type. No calibration or adjustment is required after changing the type of output signal.
In the case of voltage output signals, load requirements apply to the external device or circuit connected to the
HF3 transmitter. These requirements are defined in the “Operation” chapter
3.5 Relay outputs (HF34)
Each of the two independent SPDT relays has its own set-point which can be adjusted with a potentiometer
located on the printed circuit board. A relay is energized when the value of the monitored parameter is higher
than the corresponding set-point. Operation of each relay is indicated by a LED located on the HF34 printed
circuit board. This LED is lit when the corresponding relay is energized.
Using the ROTRONIC HW4 software any of the two relays can be made to correspond to one of the following:
Relative humidity
Temperature
Dew or frost point
If so desired, any relay can also be disabled. The minimum and maximum limits for the two adjustable set-
points (potentiometer) can be set within the numerical limits of -999.99 and 9999.99 and the dead band for
each set-point can also be adjusted.