User Manual

E-M-HF4-V1_22

Rotronic AG

Bassersdorf, Switzerland

Document code

Unit

HygroFlex HF4 Humidity Temperature

Transmitters: User Guide

Instruction Manual

Document Type

Page

5 of 29

Document title

2.1 Display and keypad option

The LC display option for the HF43 and HF45 has a

backlight. The LC display option for the HF42 does

not have a backlight.

The upper line corresponds to relative humidity or

dew / frost point and the bottom line corresponds to

temperature.

The display can be configured to show a trend indicator on each line:

▲: increasing value

▼: decreasing value

In the event of an alarm the display shows the symbol [ ! ] to the right of the value.

For instructions see the following HW4 manual: E-M-HW4v3-F2-003.

3 General description

3.1 Power supply

Depending on the circuit type, the HF4 requires the following power supply:

a) HF42 (2-wire, loop powered): 10…28 VDC - depending on the load connected to the output(s). The

minimum supply voltage can be determined as follows:

V min = 10 V + (0.02 x Load*) *Load resistance in ohms.

For the maximum load of 500 , the minimum supply voltage is 10 + (0.02 x 500) = 20 VDC. With both

output circuits closed, the maximum current consumption is 40 mA.

b) HF43 (3-wire with analog outputs): 15 to 40 VDC (see note below) or 12 to 28 VAC. With both output

circuits closed, the maximum current consumption is 50 mA.

Note: depending on the type of output signal, the HF43 will operate with the following minimum voltage

0…1 V outputs: 5 VDC or 5 VAC

0…5 V outputs: 10 VDC or 8 VAC

0…10 V outputs: 15 VDC or 12 VAC

0…20 mA or 4 …20 mA outputs: 6 VDC or 5 VAC with 0 load

15 VDC or 12 VAC with 500 load

c) HF45 (3-wire) with digital outputs: 5 to 40 VDC or 12 to 28 VAC. Maximum current consumption:

Model with USB interface: 50 mA

Model with Ethernet (TCP/IP) interface: 300 mA

3.2 Measured parameters

The HF4 measures relative humidity with a ROTRONIC Hygromer

IN1 capacitive sensor and temperature

with a Pt100 RTD.